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Effects of wood fiber properties on mold resistance of wood polypropylene composites
... The water-related thermal properties of LCB-based materials are also of high importance to be investigated [5] because varying humidity impacts not only biodeterioration but also the thermal properties [13,14]. Some natural mold resistance associated with the chemical composition of different wood species containing antifungal compounds was revealed on wood flour [15] and wood-plastic composites [16]. The microbial quality (mold and bacteria) of industrial crops (flax, hemp, straw) which potentially could be used as raw materials for insulation is affected by atmospheric conditions during growing season and they always present a wide diversity of molds [17]. ...
... That phenomena could be explained by the large amount of soluble sugars, providing nutrients for mold fungi [31]. The negative effect of higher sugar contents against molds was shown on wood-plastic composites made of different wood types [16]. The soluble sugars of raw LCB used in this study with the most potential for mold is the content of hemicelluloses, which varied in range of 24-30% [29]. ...
... Polymers 2024,16, 562 ...
The present study evaluates the mold fungal resistance of newly developed loose-fill thermal insulation materials made of wheat straw, corn stalk and water reed. Three distinct techniques for the processing of raw materials were used: mechanical crushing (Raw, ≤20 mm), thermo-mechanical pulping (TMP) with 4% NaOH and steam explosion pulping (SEP). An admixture of boric acid (8%) and tetraborate (7%) was applied to all processed substrates due to their anti-fungal properties. The fourth sample group was prepared from SEP substrates without added fungicide (SEP*) as control. Samples from all treatments were separately inoculated by five different fungal species and incubated in darkness for 28 days at 28 °C and RH > 90%. The highest resistance to the colonization of mold fungi was achieved by TMP and SEP processing, coupled with the addition of boric acid and tetraborate, where molds infested only around 35% to 40% of the inoculated sample area. The lowest mold fungi resistance was detected for the Raw and SEP* samples, each ~75%; they were affected by rich amount of accessible nutrients, suggesting that boric acid and tetraborate additives alone did not prevent mold fungal growth as effectively as in combination with TMP and SEP treatments. Together, the achieved fungal colonization scores after combined fungicide and pulping treatments are very promising for the application of tested renewable materials in the future development of thermal insulation products.
... Neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents were determined using an ANKOM fiber analyzer (model: A2000i; manufactured by Anke Borealis Technology Co., Ltd. in Beijing, China) according to Van Soest 15 et al. Anthrone colorimetry was used to assess the content of water-soluble carbohydrates (WSC) in the material 16 . ...
... The characteristic peaks of sorghum straw were all significantly reduced after extrusion puffing. Characteristic peaks appeared at 2θ of 16 that the cellulose in sorghum straw is a crystalline structure of type I cellulose. The substance corresponding to the strongest peak (200) is C 16 H 14 O 5 [14387- , which occurs at 2θ equal to 22.2°, and the substance with the next highest peak (006) is C, which occurs at 2θ equal to 26.6°. ...
In this study, the effects on silage performance and microbial community of sorghum straw treated with the addition of enzymes (cellulase (CE), xylanase (XE)) and extrusion puffing technology, combined with SEM, XRD, and FTIR techniques, were thoroughly investigated. The results showed that the enzyme preparations, especially xylanase, significantly improved the nutritional value and fermentation efficiency of straw and enhanced the silage effect. Extruding significantly changes the surface structure of the straw, increasing the surface area and porosity, and promoting the attachment of microorganisms. This study not only optimized the sorghum straw silage performance but also provided technical support for the efficient use of straw resources, which is of great significance for the sustainable development of animal husbandry and the resource utilization of agricultural waste.
... At the same time, the tree has the characteristics of strong germination, fast growth, resistance to salt stress, heavy metals and air pollution, and has been used as a pioneer plant in polluted areas (Li et al., 2012;Zhang et al., 2013;Zhao et al., 2014). Compared with other woody plants, B. papyrifera is rich in flavonoids, polyphenols, and fructose (Feng et al., 2019), which may be the reason why B. papyrifera has been used as a traditional Chinese medicine for a long history (Feng et al., 2008). For instance, prenylflavone derivatives from B. papyrifera have an inhibitory effect on cancer cells , and polyphenols from B. papyrifera can inhibit coronavirus protease (Park et al., 2017). ...
... So far, little was known about the flavonoid-regulated genes in B. papyrifera leaves. Relevant molecular studies have only demonstrated that four key enzyme families (CHS, F3'H, I2'H, and DFR) in the flavonoid synthesis pathway exhibited significant expansion (Peng et al., 2014;Feng et al., 2019). The high flavonoid abundance and strong disease resistance of B. papyrifera may originate from these expanded gene families. ...
Flavonoids are important secondary metabolites involved in plant development and environmental responses. Sex differences in flavonoids are common in plants. Broussonetia papyrifera is a dioecious plant that is rich in flavonoids. However, few studies have been done on its molecular mechanism, especially sex differences. In the present study, we performed an integrated transcriptomics and metabolomics analysis of the sex differences in the accumulation of flavonoids in B. papyrifera leaves at different developmental stages. In general, flavonoids accumulated gradually with developmental time, and the content in female plants was higher than that in male plants. The composition of flavonoids in female and male plants was similar, and 16 kinds of flavonoids accumulated after flowering. Correspondingly, a significant enrichment of differentially expressed genes and metabolites was observed in the flavonoid biosynthesis pathway. WGCNA and qRT-PCR analyses identified several key genes regulating the accumulation of flavonoids, such as those encoding CHS, CHI and DFR. In addition, 8 TFs were found to regulate flavonoid biosynthesis by promoting the expression of multiple structural genes. These findings provide insight into flavonoid biosynthesis in B. papyrifera associated molecular regulation.
... The relatively high contents of cedrol, stigmast-4-en-3-one, and 8-propoxy-cedrane in Chinese fir provided the corresponding WPC with significant resistance to mold growth. Meanwhile, the relatively low contents of α-Cedrene, β-cedrene, α-cadinol, and γ-sitosterol were beneficial for mitigating the biodegradation of WPC [21]. ...
... Mold colonization of PP-based WPC with various wood species: (a) poplar, (b) MOSO-bamboo (c) Chinese fir (d) Ramin, (e) pine, ( f) gum, (g) cedar, (h) rubberwood[21]. ...
Wood plastic composites (WPCs) is one of crucial and potential engineering wood products that has been extensively employed in the fields of landscape, transportation, municipal engineering and building construction. It has gradually been used to replace the conventional wood-based composites. This chapter aims to introduce the properties and development of WPCs and illustrate how defects in their mechanical properties, biological and aging resistance, and flame retardance affect their global development. Herein, the effects on the biological durability of WPCs against algae, mold, fungi, and termites made with various wood species with different chemical extractive compositions, the natural weathering performance of WPCs and the mechanisms of protection against ultraviolet light and moisture, the effectiveness and mechanism of reinforcement of WPCs by novel alloy modification of linear and aromatic polyamides are reviewed. Additionally, the flame retardance properties, common testing methods as well as the performances of novel flame retardants for WPCs, are comparatively described. Lastly, the limitations and prospects of WPCs in future construction applications are also discussed.
... According to Ramakrishnan et al. (2022), as the moisture level increases, the material's flexibility gradually diminishes, accompanied by an incremental rise in the material's weight ultimately contributing to discomfort. Furthermore, excessive moisture content in textile material can create a favorable environment for mold growth, which develops an unpleasant odor and damage and poses health risks (Feng et al. 2019). Moisture content (MC) and moisture regain (MR) of the BC are shown in Fig. 1, with the range of 7.9-21.3% ...
Kombucha is a popular fermented beverage that involves fermentation using a symbiotic culture of bacteria and yeast (SCOBY) and produces bacterial cellulose (BC). Carbon and nitrogen sources are essential in kombucha processing and BC production. However, studies on cost-effective BC production as an alternative source of leather have remained scarce. This study aimed to assess the effects of various nitrogen and carbon sources on the production of kombucha BC, investigate the qualities, and dye the product using natural colorant. Different nitrogen sources (such as black tea, white tea, and green tea) and carbon sources (honey, sugar cane, palm sugar, and brown sugar) were used to produce kombucha BC, as well as to appraise the product qualities, which were dyed using three distinct natural dyes (coffee, ginger, and sappan wood). The results revealed that different nitrogen and carbon sources produced different BC with different properties. Green tea (N-source) and palm sugar (C-source) containing medium produced a BC thickness of 0.194 ± 0.04 mm with the highest tensile strength (24.42 ± 3.90 g). Different dyes also result in the fabric having different colors: brownish yellow (coffee), yellowish orange (ginger), and red (sappan wood). All BC products showed color stability after 8 months of storing at room temperature. In conclusion, effective BC production could use green tea and palm sugar as the best nitrogen and carbon sources, respectively. Dyed BC showed good visual quality and is promising for its eco-friendly and sustainable application in fashion products.
... The nutritive flour was dispersed in distilled water (1 : 10, w/v) at 100°C in a thermostatic water bath (HWS-28, Shanghai, China) for 30 min, and the extracts were collected and adjusted to 100 mL using distilled water. The total soluble sugar content was measured using the anthrone colorimetric method at a wavelength of 620 nm (L4 intelligent UV-Vis spectrophotometer, Shanghai Youke Instrument Co. Ltd., Shanghai, China), as described previously [25]. ...
Antioxidants are primarily responsible for the beneficial health effects of foxtail millet. This study evaluated a foxtail-millet-based composite antioxidant nutritive flour consisting of fermented foxtail millet, coarse grains, and fruit powders. The composition of the antioxidant nutritive flour was optimized, and it was found to be rich in antioxidant nutrients, such as phenolics (2.27 g/100 g), vitamin C (0.21 g/100 g), and polysaccharides (0.35 g/100 g). The results revealed that this composite nutritive flour has enhanced in vitro and in vivo physicochemical properties and higher antioxidant activities than commercial nutritive flour. The total antioxidant capability, superoxide dismutase (SOD) capability, and superoxide radical scavenging abilities were 0.84 mM Trolox equivalents/g, 38.29 U/g, and 42.02%, respectively. The activity of the antioxidant enzyme SOD and glutathione peroxidase increased, whereas malondialdehyde levels decreased in the liver, heart, and kidney of mice treated with the nutritive flour, indicating the potential antioxidant activity of this fermented foxtail-millet-based nutritive flour.
... The surface of the BPC was completely covered by mold on the 28th day, showing that the BPC had weak anti-mold activity. The unmodified BPC was easily attacked by mold fungi due to hygroscopic hydroxyl groups on the surface of BF, which provided essential conditions for mold growth (Feng et al., 2019). On the contrary, no mold was observed on the surface of the BPC-TiO 2 -F after 28 days of cultivation, indicating that the superhydrophobic surface kept the BPC-TiO 2 -F in a relatively dry state because the water droplet could not remain on its surface. ...
Bamboo fiber/polypropylene composites (BPCs) have been widely used in buildings, interior decoration, and automobile components. However, pollutants and fungi can interact with the hydrophilic bamboo fibers on the surface of Bamboo fiber/polypropylene composites, degrading their appearance and mechanical properties. To improve their anti-fouling and anti-mildew properties, a superhydrophobic modified Bamboo fiber/polypropylene composite (BPC-TiO2-F) was fabricated by introducing titanium dioxide (TiO2) and poly(DOPAm-co-PFOEA) onto the surface of a Bamboo fiber/polypropylene composite. The morphology of BPC-TiO2-F was analyzed by XPS, FTIR, and SEM. The results showed that TiO2 particles covered on Bamboo fiber/polypropylene composite surface via complexation between phenolic hydroxyl groups and Ti atoms. Low-surface-energy fluorine-containing poly(DOPAm-co-PFOEA) was introduced onto the Bamboo fiber/polypropylene composite surface, forming a rough micro/nanostructure that endowed BPC-TiO2-F with superhydrophobicity (water contact angle = 151.0° ± 0.5°). The modified Bamboo fiber/polypropylene composite exhibited excellent self-cleaning properties, and a model contaminant, Fe3O4 powder, was rapidly removed from the surface by water drops. BPC-TiO2-F showed excellent anti-mold performance, and no mold was on its surface after 28 days. The superhydrophobic BPC-TiO2-F had good mechanical durability and could withstand sandpaper abrasion with a weight load of 50 g, finger wiping for 20 cycles, and tape adhesion abrasion for 40 cycles. BPC-TiO2-F showed good self-cleaning properties, mildew resistance, and mechanical resistance, giving it promising applications for automotive upholstery and building decoration.
... Cedarwood also has a very high level of resistance to mold because it belongs to the group of hardwoods which incidentally has dense pores so that moist water does not easily enter and cause mold. That is why the quality of cedar is the main point of concern [2]. Like wood in general, cedarwood also has a variety of qualities depending on the factors of sawing and the age of the tree, so these quality factors can be classified directly by paying attention to the color, texture, and pattern of the fiber [3], [4]. ...
... Bamboo is an important natural fibre resource, with more than 70 genera and 1200 species of bamboo plants worldwide [2]. China's bamboo plant resources rank first in the world, known as the Kingdom of Bamboo [3]. In natural fibre composites, only short-cut fibres and long fibres with a certain length have a reinforcing effect on polymer resins [4]. ...
In the context of carbon neutrality, it is of good economic and ecological value to replace synthetic fibres with natural fibres as reinforcing materials in the preparation of composites. The effect of the hot pressing process parameters on the physical and mechanical properties of the LBF/PP composites was further investigated. The distribution of LBF in the composites was observed by CT. The experimental results show that the hemicellulose content of the BF decreases and the lignin content decreases after the alkali treatment. The mechanical properties of the LBF/PP composites were better at a hot pressing temperature of 180°C, a hot pressing pressure of 8 MPa, a hot pressing time of 15 min and a mass fraction of 70% LBF, with bending strength and bending modulus reaching 226.1 MPa and 15.1 GPa respectively. CT results show that the fibres are evenly distributed in the composites and that the hot pressing process allows the molten PP to penetrate the pores of the LBF surface, forming a good physical and mechanical bond. These composites can be used in various applications such as construction, automotive, consumer goods etc. They are considered to be a suitable alternative to solid plastic products and materials.
... Bradford, 1976) using bovine serum albumin as the calibration standard. SS content was measured using anthrone colorimetry (Feng et al, 2019). The concentration of proline was determined according to ninhydrin colorimetry (Khoma et al, 2021). ...
Mangroves are unique forest communities with an abundance of species, high productivity and high ecological, social and economic value. Evaluation of the stress resistance of mangrove plants has mainly focused on the effects of high salinity, heavy metals and flooding, with fewer studies evaluating resistance to upwelling stress. Mangrove species of Avicennia marina, Aegiceras corniculatum and Kandelia obovata were submitted to three temperature upwelling (5, 10 and 15°C) and several physiological and biochemical parameters were measured at six time points (0, 6, 12, 24, 72 and 168 h). The data demonstrated: a certain amount of damage occurred to mangrove plants in the face of prolonged upwelling; different mangrove plants have different response strategies to upwelling; mangrove plants are not sensitive to different upwelling temperatures; the resistance of mangrove plants to upwelling stress was in the following order: A. marina< K. obovata< A. corniculatum. Markers of damage such as relative electrical conductivity (REC), malondialdehyde (MDA) and reactive oxygen species (ROS) among all mangrove species were significantly higher with prolonged upwelling stress. The contents of photosynthetic pigments in all three mangrove species also increased. Superoxide dismutase activity (SOD) was maintained at a high level in both control and treatment groupss. By contrary, the change of peroxidase activity (POD) of A. marina and K. obovata was larger than that of A. corniculatum. Catalase activity (CAT) in A. marina and K. obovata significantly increased under upwelling at both 5 and 10°C while there was no obvious variation of CAT in A. corniculatum. Soluble protein and Soluble sugar contents showed no clear variation but stayed at fairly high levels. However, proline content in A. corniculatum significantly increased under long-term upwelling stress while this was not the case in the other two species. High correlation could be observed between A. marina and MDA, O2- and POD in PCA while A. corniculatum showed association with proline and soluble sugar. In conclusion, the ability of A. corniculatum to tolerate upwelling stress might be due mainly to increases in the activities of SOD and the inducing of proline biosynthesis, while, A marina and K. obovata tolerated upwelling stress by adjusting activity levels of SOD, POD and CAT. Segregation in both principal component analysis (PCA) and hierarchical cluster analysis (HCA) further indicated different tolerances and resistances to upwelling between the three species. Our study provides new insights into the stress response of mangroves to upwelling.
... The enzymatic activities of SOD, CAT, APX, and POD were determined by the nitro-blue tetrazolium (NBT) photoreduction method (52), the hydrogen peroxide decomposition method (53), the ascorbic acid method (54), and the guaiacol method (55), respectively. Soluble sugar content in maize leaves was measured by the anthrone method (56). Proline content was determined according to the method of Bates et al. (57). ...
Root-associated microorganisms are widely recognized as playing an important role in mitigating stress-induced damage to plants, but the responses of rhizosphere microbial communities after inoculation and their relationship with plant responses remain unclear. In this study, the bacterium Providencia vermicola BR68 and the fungus Sarocladium kiliense FS18 were selected from among 91 strains isolated from the halophyte Suaeda salsa to interact with maize seedlings under salt stress. The results showed that compared with NaCl-only treatment, inoculation with strains BR68 and FS18 significantly improved the growth, net photosynthetic rate, and antioxidant enzyme activities of maize; significantly reduced proline content and generation rate of reactive oxygen species (ROS); and alleviated oxidative stress and osmotic stress. Moreover, inoculation with these two strains increased the activities of soil microbiome enzymes such as sucrase, catalase, and fluorescein diacetate hydrolase, which improved maize physiologies and promoted maize growth under salt stress. In addition, these inoculated strains significantly affected the abundance of certain genera, and the correlation trends for these genera with soil properties and maize physiologies were similar to those of these inoculated strains. Strain BR68 was indirectly associated with bacterial communities through BR-specific biomarkers, and bacterial communities and soil properties explained most of the variation in maize physiologies and growth. Inoculation of strain FS18 was directly associated with variations in soil properties and maize physiologies. The two strains improved maize growth under salt stress and alleviated stress damage in maize in different ways. The links among salt-tolerant microorganisms, soil, and plants established in this study can inform strategies for improving crop cultivation in salinized lands.
... Culm wall thickness and culm cross sectional area were measured and calculated in the middle of internode using a vernier caliper (Digital Caliper 0-100 mm, Lugong Inc., Xiamen, China) [12]. The content of soluble sugar was determined by anthrone colorimetry [13]. The contents of cellulose, Si, and lignin were measured according to the method described by Zhang et al. [14]. ...
The objective of this study was to determine the effect of seaweed oligosaccharide synergistic silicate (Si) fertilizer (SOSSiF) on rice resistance to lodging stress. The results showed that a spraying SOSSiF decreased apparent lodging index and enhanced rice yield significantly under a high N level. The spraying test indicated that the apparent lodging rate of rice was the lowest when SOSSiF was sprayed for four times, and the dosage was 45 kg/ha each time. Morphological and anatomical analysis indicated that SOSSiF decreased plant height and the lower internode length of ZCSM and increased culm cross-sectional area and wall thickness of JNSM significantly compared with the control. Furthermore, SOSSiF enhanced bending strength of rice culm by 38.8% to 63.6%, and reduced lodging index by 36.8% to 42.6%. Chemical component analysis found that SOSSiF elevated the contents of soluble sugar, cellulose, Si, and lignin in the culms of ZCSM and JNSM. Correlation analysis revealed that the lodging index was positively correlated with the length of the lower internode, and was negatively correlated with culm bending strength and culm thickness. The above results suggested that spraying SOSSiF elevates culm contents of Si and lignin and enhances bending strength, thus improving rice lodging resistance and production.
... Under the action of concentrated sulfuric acid, sugar can undergo dehydration to generate uronic acid or hydroxymethyl furfural, both of which can be combined with anthrone to generate a blue-green uronic derivative. Within a certain range, the shade of the color is indicative of sugar content [30,31]. In turn, soluble protein yielded a cyan coloring after binding to Coomassie Brilliant blue G-250 in a dilute acid environment, and the absorbance was measured at 595 nm. ...
Cold stress inhibits rice germination and seedling growth. Brassinolide (BR) plays key roles in plant growth, development, and stress responses. In this study, we explored the underlying mechanisms whereby BR helps alleviate cold stress in rice seedlings. BR application to the growth medium significantly increased seed germination and seedling growth of the early rice cultivar “Zhongzao 39” after three days of cold treatment. Specifically, BR significantly increased soluble protein and soluble sugar contents after three days of cold treatment. Moreover, BR stimulated the activity of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase; thereby alleviating cold-induced damage and increasing glutathione content and the GSH/GSSG ratio while concomitantly reducing H2O2 content. BR upregulated the expression levels of cold-response-related genes, including OsICE1, OsFer1, OsCOLD1, OsLti6a, OsSODB, OsMyb, and OsTERF2, and downregulated that of OsWRKY45, overall alleviating cold stress symptoms. Thus, BR not only upregulated cellular osmotic content and the antioxidant enzyme system to maintain the physiological balance of reactive oxygen species under cold but, additionally, it regulated the expression of cold-response-related genes to alleviate cold stress symptoms. These results provide a theoretical basis for rice breeding for cold resistance using young seedlings.
... More recently, this concept has been extended to wood plastic composites (WPC). For example, Feng et al. showed that the mould resistance of a polypropylene WPC was enhanced when the filler was a durable wood species, and they suggested that 'their' approach provided an alternative solution (compared to chemicals) to improve the durability of WPCs against (c) Tracheids in cypress pine heartwood showing resinous material covering the wood cell wall (arrowed); (d) Residues (sawdust and wood chips) produced by the milling of cypress pine logs into sawn timber; (e) Positive effect of including cypress pine on the resistance of medium density fibreboard to attack by the subterranean termite, Coptotermes lacteus fungal attack [43]. This study and previous research on panel products have clearly demonstrated the potential to manufacture biocide-free durable wood composites from naturally durable woods. ...
Purpose of Review
Wood can be protected from biological deterioration thereby prolonging its longevity and contribution to carbon sequestration. Wood protection is only useful if it is inexpensive and can be done at scale, and with minimal adverse environmental impacts. It is difficult to meet all these criteria but some approaches come close. They are described in this paper with an emphasis on new research findings and directions to inform current research on carbon sequestration by wood.
Recent Findings
Research on wood protection with the exception of nano-wood preservatives is gradually shifting away from the use of synthetic biocidal chemical treatments to the use of naturally durable wood or protectants and treatments that deny organisms access to wood (barriers) or restrict essential requirements for their growth. The latter approach is attracting attention, and welcome new entrants to the field of wood protection, because of its potential to enhance carbon sequestration at a meaningful scale.
Summary
We expect increasing regulatory and cost pressure on traditional approaches to wood protection using synthetic biocides and an acceleration of the trend evident in the recent past of protecting wood by modifying its molecular structure to exclude water, or growing trees in plantations that produce naturally durable wood. The strengthening of this trend will create many opportunities to research the properties and applications of ‘new’ durable wood products. In addition, we predict a major reorientation of the field to develop, test and model novel approaches to wood protection for atmospheric carbon sequestration. We conclude that future work will likely include research on protection of: (1) novel cellulose or lignin composites used as replacements for plastic; (2) massive timber composites used in tall buildings and other large infrastructure; (3) huge quantities of low-quality wood used specifically for carbon containment.
... This is probably due to the greater availability of large particles for microorganisms, while smaller particles (less than 10 mesh) are better surrounded by the polymer matrix and thus less accessible to fungi. The influence of the type of filler on WPC susceptibility to mold was also demonstrated by Xu et al. [42], Feng et al. [34] and Feng et al. [43], Valentín et al. [44] stated that pine bark can be an excellent source of nutrients for fungi. So et al. [45], in the study of litter, revealed that bark particles are more susceptible to mold growth than coniferous chips used under the same conditions. ...
Due to the content of lignocellulosic particles, wood plastic composites (WPC) composites can be attacked by both domestic and mold fungi. Household fungi reduce the mechanical properties of composites, while mold fungi reduce the aesthetics of products by changing their color and surface decomposition of the wood substance. As part of this study, the impact of lignocellulosic fillers in the form of sawdust and bark in poly (lactic acid) (PLA)-based biocomposites on their susceptibility to mold growth was determined. The evaluation of the samples fouled with mold fungi was performed by computer analysis of the image. For comparison, tests were carried out on analogous high-density polyethylene (HDPE) composites. Three levels of composites’ filling were used with two degrees of comminution of lignocellulosic fillers and the addition of bonding aids to selected variants. The composites were produced in two stages employing extrusion and flat pressing. The research revealed that PLA composites were characterized by a higher fouling rate by Aspergillus niger Tiegh fungi compared to HDPE composites. In the case of HDPE composites. The type of filler (bark, sawdust) affected this process much more in the case of HDPE composites than for PLA composites. In addition, the use of filler with smaller particles enhanced the fouling process.
... In polypropylene composites with wood flour, the origin of the wood flour was also observed. The antifungal activity of wood flour from Chinese white poplar (Populus tomentosa), moso-bamboo (Phyllostachys heterocycla), Chinese fir (Cunninghamia lanceolata), Ramin (Gonystylus bancanus), Chinese white pine (Pinus armandii), river red gum (Eucalyptus camaldulensis), western red cedar (Thuja plicata), and rubberwood (Hevea brasiliensis) was tested against A. niger, Trichoderma viride, Penicillium funiculosum, Aureobasidium pullulans, and Chaetomium globosum [92]. The authors concluded that the mold growth resistance depended on the wood origin, with Chinese fir, red gum, and red cedar showing better activity against the fungi tested. ...
Pathogenic microbes are a major source of health and environmental problems, mostly due to their easy proliferation on most surfaces. Currently, new classes of antimicrobial agents are under development to prevent microbial adhesion and biofilm formation. However, they are mostly from synthetic origin and present several disadvantages. The use of natural biopolymers such as cellulose, hemicellulose, and lignin, derived from lignocellulosic materials as antimicrobial agents has a promising potential. Lignocellulosic materials are one of the most abundant natural materials from renewable sources, and they present attractive characteristics, such as low density and biodegradability, are low-cost, high availability, and environmentally friendly. This review aims to provide new insights into the current usage and potential of lignocellulosic materials (biopolymer and fibers) as antimicrobial materials, highlighting their future application as a novel drug-free antimicrobial polymer.
... Soluble sugar concentrations were measured using anthrone colorimetry following the method by Jing et al. [26]. Weighted fresh leaves (0.2 g) were cut into pieces and put into a triangular flask, then 20 mL distilled water was added and the triangular flask was sealed with plastic film and extracted in boiling water for 30 min. ...
The increasing soil salinity levels under reclaimed water irrigation have a negative effect on plant growth. Greenhouse experiments were conducted in 2018 and 2019 under reclaimed water–fresh water combined irrigation. After transplanting (Day 1), rice was irrigated with clean water (tap water) for 10 days to facilitate rice root colonisation. Subsequently, rice was irrigated with reclaimed water for 50 days (Day 11 to 60), and then irrigated with clean water. B. subtilis and S. cerevisiae were mixed with clean water (tap water) and irrigated into soil at Day 61. B. subtilis (20 billion colony-forming units/g) and S. cerevisiae (20 billion colony-forming units/g) were mixed at the following proportions: 5 g and 0 (J1), 3.75 g and 1.25 g (J2), 2.5 g and 2.5 g (J3), 1.25 g and 3.75 g (J4), and 0 and 5 g (J5), respectively; rice treated with reclaimed water (CK) and clean water (J0) with no microorganisms applied were also used. We measured NO3--N and NH4+-N concentrations and electrical conductivity (EC) in the soil at 0–5, 5–15, and 15–25 cm layers; root activity; and malondialdehyde (MDA), soluble sugar, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutamine synthetase (GS) activity in leaves at Day 71. B. subtilis and S. cerevisiae combination could promote rice physiological indices, and B. subtilis had a greater effect than S. cerevisiae. There are obvious differences in the physiological performance and soil N between 2018 and 2019 due to the EC of reclaimed water. Redundancy analysis revealed that soil NO3−-N and the mass of B. subtilis applied were major factors influencing leaf physiological indices. Five grams of B. subtilis is recommended to facilitate rice growth after irrigation with reclaimed water. Our research provides a new agronomic measure for the safe utilisation of reclaimed water.
... Therefore, further thermal treatment had to be carried out. Moreover, the moisture content of WB particles used for this study was similar to those presented in [23,24]. They stated that a moisture content below 12.5% is the most suitable for preparing WPCs because it could prevent fungal attack. ...
In order to construct sustainable and approachable buildings it is necessary to develop efficient building materials (thermal insulation, structural and sound-absorbing) with lower environmental impact, especially regarding the carbon footprint. Therefore, this study examines a wood-plastic composite (WPC) from wood bark particles and rapeseed oil-based binding material. The advantage of this WPC is sufficient thermal insulation and self-bearing properties for structural application. Additionally, thermal treatment or loading conditions during production are not required, which is energy and cost-efficient. WPCs were produced from different ratios of binding material and wood bark particles, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95 and 1.0. The highest strength characteristics are found with the WPC-0.85 samples, however, water resistance properties such as water absorption and thickness swelling after 28 days of immersion are only reasonable. The WPC obtained at 0.85 binding material/wood bark particles ratio is characterised by density – 357 kg/m³, thermal conductivity – 0.0706 W/(m·K), compressive strength – 1.8 MPa, bending strength – 1.2 MPa, tensile strength – 0.23 MPa, water absorption by total immersion – 38.2 vol% and thickness swelling – 2.5%.
Purpose
In this paper, we use Pinus pumila (Pall.) Pinecone to extract essential oil and improve its utilization.
Methods
The study used hydrodistillation to extract essential oil from Pinus pumila (Pall.) pinecone. Inhibition analysis of E. coli using extracted essential oils was evaluated to reveal the inhibitory activity by assessing growth curves, conductivity, nucleic acids, proteins, enzyme activities, and protein synthesis.
Results
The primary constituents, as shown by GC-MS chemical composition study, were α-pinitol, β-pinene and limonene. The results of the bacteriostatic activity indicated that the inhibitory zone (DIZ) had a diameter of 14.93 ± 0.14 mm, the minimum bactericidal concentration (MBC) was 16.0 µL/mL, and the minimum inhibitory concentration (MIC) was 8.0 µL/mL. Sweeping electron microscopy and laser confocal also demonstrated the disruption of cell wall and cellular enzymes, analyzed by CATase and ATPase activities, which showed a decrease in enzyme activity, and SDS-PAGE analysis showed its ability to inhibit protein synthesis, which leads to cellular damage.
Conclusion
The present study emphasizes the sustainable use of Pinus pumila (Pall.) Pinecone for economic opening of food preservation in addition to inhibition of spoilage bacteria.
Purpose The aim of this paper was to use Pinus pumila (Pall.) Pinecone from Northeast China to extract essential oils to inhibit Escherichia coli and improve its utilization. Methods The study used hydrodistillation to extract essential oil from Pinus pumila (Pall.) pinecone. Inhibition analysis of E.coli using extracted essential oils was evaluated to reveal the inhibitory activity by assessing growth curves, conductivity, nucleic acids, proteins, enzyme activities, and protein synthesis. Results The primary constituents, as shown by GC-MS chemical composition study, were α-pinitol, β-pinene and limonene. The results of the bacteriostatic activity indicated that the inhibitory zone (DIZ) had a diameter of 14.93±0.14 mm, the minimum bactericidal concentration (MBC) was 16.0 µL/mL, and the minimum inhibitory concentration (MIC) was 8.0 µL/mL. Sweeping electron microscopy and laser confocal also demonstrated the disruption of cell wall and cellular enzymes, analyzed by CATase and ATPase activities, which showed a decrease in enzyme activity, and SDS-PAGE analysis showed its ability to inhibit protein synthesis, which leads to cellular damage. Conclusion The present study emphasizes the sustainable use of Pinus pumila (Pall.) Pinecone for economic opening of food preservation in addition to inhibition of spoilage bacteria.
Bambusicolous fungi inhabit bamboo tissues and play vital roles in bamboo ecosystems, mostly composed of saprobes, epiphytes, pathogens, and endophytes. Each category of fungus plays a distinct role: saprobes aid in decomposition, endophytes and epiphytes enhance plant health by establishing biochemical defense barriers, while pathogens can cause harmful effects like abnormal growth or death, thereby significantly influencing the overall health and quality of bamboo forests. In China, there is a rich diversity of bambusicolous mycopathogens but the information is scattered across various literature. Therefore, there is a need to systematically consolidate and provide an updated list of bambusicolous mycopathogens. This paper presents a comprehensive taxonomic account of bambusicolous mycopathogens in China with the following objectives: 1) to describe new specimens collected from Sichuan Province based on morphology and multigene phylogeny; 2) to update our current knowledge on the biodiversity of mycopathogens from China; 3) to discuss further research directions or areas. We have systematically gathered taxonomic information from diverse literature sources, such as articles, monographs, taxonomic websites, and other materials, to identify and screen fungal species associated with various bamboo diseases, including culm base rot, culm/timber rot, culm/leaf rust, dieback, shoot blight, rhombic spot, branch blight, witch's broom, tar spot, and leaf spot/blight. We have documented a total of 336 bambusicolous mycopathogens, providing additional details on host species, geographical distribution, disease type, epiphytology, and phylogenetic relationships based on DNA sequence data. The bambusicolous mycopathogens belong to 161 genera, 89 families, 41 orders, 11 classes and three phyla. Ascomycota (272 species, 133 genera), is predominant among these bambusicolous mycopathogens. Within this phylum, Sordariomycetes (159 species, 61 genera) have the most species, followed by Dothideomycetes (78 species, 50 genera), Eurotiomycetes (23 species, nine genera), Ascomycota genera incertae sedis (eight species, eight genera), Leotiomycetes (two species, two genera), Lecanoromycetes (one species, one genus), and Pezizomycetes (one species, one genus). Within the Basidiomycota (60 species, 25 genera), the majority of species (55%) are in Pucciniomycetes (33 species, five genera), followed by Agaricomycetes (25 species, 18 genera), Exobasidiomycetes (one species, one genus), and Ustilaginomycetes (one species, one genus). Only four species (three genera) in the Mucoromycota were recorded. The top five largest bambusicolous mycopathogenic orders include Hypocreales, Phyllachorales, Pleosporales, Pucciniales, and Xylariales, comprising 39, 39, 32, 30, and 22 species, respectively. The most species-rich genera are Phyllachora (33 species, Sordariomycetes), Puccinia (25 species, Pucciniomycetes), Fusarium (15 species, Sordariomycetes), Apiospora (12 species, Sordariomycetes), Colletotrichum (nine species, Sordariomycetes), Aspergillus (seven species, Eurotiomycetes), and Penicillium (seven species, Eurotiomycetes). In addition, our freshly collected specimens unveil 23 species across nine orders within four classes, including a new genus, 12 novel species, 11 previously unreported host associations, and seven new geographical records. These species are associated with diseases based on symptoms observed or based on previous studies reporting their potential pathogenicity. Future in vitro studies are needed to verify the pathogenic nature of these bambusicolous fungi via Koch’s postulates.
Broussonetia papyrifera is an important environmental restoration tree emerging in recent years, who has a good ability to resist heavy metal pollution such as Mn and Cd. In order to explore the content changes of different components of B. papyrifera’s fruits under Mn stress, the content characteristics of the chemical compounds and antioxidant capacity were determined in the study, comparing Mn mining area with control. The content of total sugar and total protein of B. papyrifera fruits in the Mn mining area is not significantly different from that in the control area, including fruits of different development stages (p > 0.05). However, the content of polyphenols, flavonoids, anthocyanins, K, Ca, Mg and Mn are significantly different (p < 0.05). Except for ABTS, the antioxidant capacity of B. papyrifera’s fruits in the Mn mining area is significantly different from that in the control area (p < 0.05). At the same time, the antioxidant activity of the fruits is closely related to the content of most chemical compounds, especially protein, sugar, polyphenols, anthocyanin, Mg and Mn. Although the Mn content in soil is low, the content of Mn in the rhizosphere soil shows a closer correlation with the content of the analyzed compounds and antioxidant activity of B. papyrifera fruits. The results show that the fruits of B. papyrifera have important development potential to be a source of polyphenols, flavonoids, anthocyanin and minerals in the process of phytoremediation, which may contributes to phytoremediation strategies.
Adequate nitrate availability throughout the strawberry life cycle improves fruit quality and productivity. However, the gene expression and metabolism patterns during nitrate-triggered developmental processes in fruits remain unknown. This transcriptome study reports the involvement of nitrate transporters and their correlated transcription factors (TFs) in the coordinate regulation of strawberry fruit development after nitrate treatment. Nitrate supply promoted plant growth and slightly delayed fruit ripening compared with the control. Nitrate also increased the contents of nitrogen, nitrogen-related metabolites, glucose, fructose, and sorbitol, but decreased the contents of several acid-related metabolites. Moreover, nitrate activated carbon and nitrogen metabolism at 25, 30, and 35 days post-anthesis (DPA). Nitrate treatment induced 10,206 differentially expressed genes (DEGs), which enriched carbon and nitrogen metabolism, amino acid, phenylpropanoid, flavonoid, terpenoid, carotenoid biosynthesis, and other metabolic pathways at 35 DPA. The DEGs also enriched GO terms for nitrate, nitrogen compound, and peptide transporter activities. Nitrate treatment significantly regulated 79 out of 164 nitrate transporter genes (FaNRTs) at 25, 30, and 35 DPA. Correlation analysis showed that strawberry adaptation to nitrate availability during fruit development involves dynamic multi-combinations between FaNRT and different TF families. qRT-PCR analysis showed that FaNPF6.3, FaNPF4.6, and FaNPF7.2 are potential nitrate signaling molecules and transporters for root nitrate uptake or removing nitrate from xylem vessels. Nitrate treatment induced FaNPF6.3, FaNPF4.6, and FaNPF7.2 expression while their correlated TFs (FaSPL8, FaNAC77-like, FaMYB1R1, and FaMYB44-like) transcription levels were down-regulated at 25 DPA. These results indicate that the spatio-temporal expression of nitrate transporters correlated with the increased nitrogen use efficiency (NUE) to enhance metabolism. The results provide a fertilizer and water management strategy for improving quality and productivity in the strawberry industry.
Mechanical toughness and mold resistance of bamboo–plastic composites (BPCs) are essential for the application on structural materials. However, limited work has used biological methods to improve these properties of BPCs. In this study, the white-rot fungus Trametes versicolor was selected to modify bamboo fibers by short-term incubation. Modified bamboo fibers were then used to reinforce high-density polyethylene to prepare BPCs. Compared to the unmodified BPCs, the BPCs pre-treated with T. versicolor showed increases in elongations at break and impact strength, and these increases became more obvious with the incubation time increased. The improved mechanical toughness was assumed to the selective removal of lignin reduced rigidity of raw materials, and the increase of specific surface areas and pore volumes enhanced mechanical interlocking of the composites. Surfaces of BPC pretreated for 15 days were free of mold spores, yielding mold inhibition efficiency of up to 100%. It suggests that metabolism of reducing sugars would efficiently improve the mold resistance of BPCs. A novel, eco-friendly bioprocess for modifying the interface between bamboo and plastic was successfully established, and it allows BPCs to be widely applied in the field of outdoor living structures.
Synthetic polymers often present increased life span, taking decades or even centuries to fully degrade in the environment. Due to the increasing demand for polymeric materials in the last decades, an overwhelming amount of waste materials are generated, creating a major pollution problem. The polymer composite industry consists of synthetic materials for matrices and reinforcements. Most of these are petroleum derivatives leading to major environmental issues. In this context, the use of renewable and biodegradable agro-based materials, such as lignocellulosic fibers, has recently increased. The lignocellulosic fiber reinforced polymer composites (LFRPC) are produced by the combination of the fibers with thermoset, thermoplastic or natural polymer matrices. Synthetic polymers are generally resistant to fungal and bacterial attack, however, vegetal fibers in the composite remains susceptible to biological degradation. Biodegradation is defined as the conversion of a material to CO2 or CH4 (under anaerobic conditions), H2O, trace inorganic products and biomass by microorganisms (bacteria, fungi, algae…). To ensure LFRPC structural stability over its service life, biodegradation mechanisms have to be properly accessed and understood. The present chapter brings an overview of the studies focusing on the biodegradability of LFRPC and the current standards/methods utilized to evaluate this property. Biodegradation can be translated as changes in the material physical properties (mass, mechanical, visual, etc.), the evolution of CO2/CH4 generated by microorganisms and the incorporation of carbon-14 labeled polymers into their biomass. Since environmental factors influence the microbial population and the activity of the different microorganisms, the symbiotic effect of abiotic degradation (weathering) combined with biotic degradation is also addressed.
Sugar is an important component affecting fruit quality and taste and has been studied in many plants. Tomatoes are consumed in very large amounts worldwide, but to date, few reports on the quantitative trait loci (QTLs) for the sugar content in tomato fruits have been published. In this study, we analyzed the genetic model of the soluble sugar content in ripe tomato fruits and the reasons for the differences. We determined that the inheritance of the soluble sugar content in tomato fruits followed a negative dominance pattern, with a predominantly polygenic effect. Moreover, we identified two chromosomal regions by bulked-segregant analysis (BSA) sequencing analysis and initially screened 47 genes that may affect the soluble sugar content of tomato fruits.
This study investigated the associations between wood species and fungal resistance, as well as the effects of fungal decay on the properties of mechanical, chemical, and water absorption of wood polypropylene composites (WPCs) filled with white poplar, moso‐bamboo, Chinese fir, Ramin, white pine, and rubber wood. Experimental results on weight losses and surface morphology both showed that fungal resistance of WPCs varied significantly with wood fiber species. Chinese fir and rubber wood filled composites separately presented the most and least durability against Coriolus versicolor (white rot) and Poria placenta (brown rot). In addition, fungal decay produced great differences in the properties of mechanical, chemical, and water absorptions between non‐decayed and decayed composites. The decayed composites showed lower MOR, tensile strength, and impact strength, as well as higher MOE and water absorptions compared with non‐decayed samples. These findings suggest that fungal decay could bring out dramatic influences on various properties of WPCs.
Wood recognition is a crucial task for wood sciences and industries, since it leads to the identification of the anatomical features and physical properties of wood. Traditionally, the recognition process relies almost exclusively on human experts, who are based on various characteristics of wood, such as color, structure and texture. However, there are numerous types of wood species in the nature that are difficult to be identified even by experienced scientists. Towards this end, in this paper we propose a novel approach for automated wood species recognition through multidimensional texture analysis. By taking advantage of the fact that static wood images contain periodic spatially-evolving characteristics, we introduce a new spatial descriptor considering each wood image as a collection of multidimensional signals. More specifically, the proposed methodology enables the representation of wood images as concatenated histograms of higher order linear dynamical systems produced by vertical and horizontal image patches. The final classification of images, i.e., histogram representations, into wood species, is performed using a Support Vector Machines (SVM) classifier. For the evaluation of the proposed method, a dataset, namely “WOOD-AUTH”, consisting of more than 4200 wood images (from cross, radial and tangential sections of normal wood structure) of twelve common wood species existing in Greek territory, was created. Experimental results presented in this paper show the great potential of the proposed methodology, which, despite a small number of misclassification cases with regards to both anatomically similar and different species, outperforms a number of state of the art approaches, yielding a classification rate of 91.47% in wood cross sections.
Acacia saligna wood was impregnated with 5% and 10% concentrations of Paraloid B-72/TiO2 nanocomposites using a soaking technique and evaluated for their antifungal activity against the growth of three molds in vitro, namely, Alternaria tenuissima, Trichoderma harzianum, and Fusarium culmorum. The Titanium (Ti) element peak of 0.14% and 0.23%, was found in the A. saligna wood treated with Paraloid B-72/TiO2 nanocomposites at 5% and 10%, respectively. Consolidant polymer Paraloid B-72 mixed with TiO2 nanocomposites at 5% and 10% showed antifungal activity against the three studied molds, while the linear growth of the studied molds reached the maximum in the control and Paraloid B-72 treatments. The results concluded that using synthesized Paraloid B-72/TiO2 nanocomposite could be considered as a new agent in the wood preservation field by prevention of mold fungal growth over the wood surfaces.
2016 The AuthorsTrees, and their derivative products, have been used by societies around the world for thousands of years. Contemporary construction of tall buildings from timber, in whole or in part, suggests a growing interest in the potential for building with wood at a scale not previously attainable. As wood is the only significant building material that is grown, we have a natural inclination that building in wood is good for the environment. But under what conditions is this really the case? The environmental benefits of using timber are not straightforward; although it is a natural product, a large amount of energy is used to dry and process it. Much of this can come from the biomass of the tree itself, but that requires investment in plant, which is not always possible in an industry that is widely distributed among many small producers. And what should we build with wood? Are skyscrapers in timber a good use of this natural resource, or are there other aspects of civil and structural engineering, or large-scale infrastructure, that would be a better use of wood? Here, we consider a holistic picture ranging in scale from the science of the cell wall to the engineering and global policies that could maximise forestry and timber construction as a boon to both people and the planet.
Considering the resource waste and environmental burden for timber and plastic materials ending up at landfills, this study proposed upcycling wood and plastic waste into value-added wood-plastic composites (WPCs), complying with the standard requirements of flexural strength, thickness swelling, water absorption and thermal insulation. Biological deterioration is a major concern of WPCs. Bacterial survival, fungal attack and algal growth of bactericide-treated WPCs were holistically analysed. Melamine resin was adopted for impregnating anti-microbial agents on the surface. All the agents showed excellent bactericidal rate (Escherichia coli), yet poly-diallyl-dimethyl-ammonium chloride (PolyDADMAC) and silver had the lowest minimum inhibitory concentrations. In terms of weight loss and strength reduction due to fungal decay (Coriolus versicolor), PolyDADMAC, silver and cetyltrimethylammonium bromide (CTAB) imparted the highest resistance on the WPCs. Moreover, PolyDADMAC and copper provided the most protection against algal growth (Chlorella vulgaris), and the former presented durable inhibitory effect. This study presents a value-added solution to wood/plastic waste recycling.
Trees, and their derivative products, have been used by societies around the world for thousands of years. Contemporary construction of tall buildings from timber, in whole or in part, suggests a growing interest in the potential for building with wood at a scale not previously attainable. As wood is the only significant building material that is grown, we have a natural inclination that building in wood is good for the environment. But under what conditions is this really the case? The environmental benefits of using timber are not straightforward; although it is a natural product, a large amount of energy is used to dry and process it. Much of this can come from the biomass of the tree itself, but that requires investment in plant, which is not always possible in an industry that is widely distributed among many small producers. And what should we build with wood? Are skyscrapers in timber a good use of this natural resource, or are there other aspects of civil and structural engineering, or large-scale infrastructure, that would be a better use of wood? Here, we consider a holistic picture ranging in scale from the science of the cell wall to the engineering and global policies that could maximise forestry and timber construction as a boon to both people and the planet.
Freshly harvested palm trunks and timber with their high moisture content (MC) are susceptible to fungi due to the high content of easily consumable sugars and starch as long as MC of the tissue is above fiber saturation point (FSP). To test the influence of sugars and starch on fungal development, small wood samples from oil palm (Elaeis guineensis) were watered and their contents of the non-structural carbohydrates were measured. Glucose was the most abundant substance in the extract, followed by starch, fructose, and sucrose. Watering for 3 and 10 days with daily water exchange reduced the content of sugars and starch considerably. Untreated and watered samples were then subjected to spore suspensions of the moulds Aspergillus niger, Penicillium commune, to a natural infection by air-born spores and to the blue-stain-fungi Alternaria alternata and Aureobasidium pullulans. The former colonized the surface of the untreated samples within a few days, while the latter caused considerable mass loss. With increasing watering both fungal activities were reduced as the nutrients for the fungi were removed. The woods of E. guineensis and Phoenix dactylifera (date palm) with MC above FSP were treated with acetic and propionic acid and subsequently infected by moulds, staining and decay fungi. Short dipping in solutions of 2% acetic acid and 2% propionic acid, respectively, protected all samples for 3 months against the mould fungi. Staining fungi and wood-decay fungi were slightly inhibited by a treatment with 5% acid concentration. Treatment with these acids offers a protection technique for the practice. Their sodium salts were ineffective due to their high pH-value.
The main objective of this study was to determine the mold resistance and mechanical properties of fungicide-treated wood and bamboo flour/high density polyethylene (HDPE) composites. Zinc borate (ZB), 4,5-dichloro-2-octyl-isothiazolone (DCOIT), zinc pyrithione (ZPT), and carbendazim (MBC) were used as fungicides. Then, treated and untreated samples were exposed to mold fungi (Aspergillus niger, Trichoderma viride, Penicillium funiculosum, and Aureobasidium pullulans) for 28 days. Mechanical properties, including the tensile strength, modulus of elasticity (MOE), modulus of rupture (MOR), and impact strength of treated and untreated composites, were evaluated. The experimental results indicated that incorporation of all four fungicides greatly improved the mold resistance of wood flour/HDPE composites. ZB-, DCOIT-, and ZPT-treated bamboo flour/HDPE composites were also more resistant to mold fungi, while no inhibitory effect on mold growth was observed for MBC-treated bamboo flour/HDPE composites. In most cases, fungicides lowered the tensile strengths and MOR of wood flour/HDPE samples but increased the impact strengths of wood flour/HDPE composites and tensile strengths and MOE of bamboo flour/HDPE composites, while other mechanical properties behaved differently. Accordingly, some fungicides can be effectively used as preservatives for both wood flour/HDPE and bamboo flour/HDPE composites.
Light and electron microscopy have contributed significantly to revolutionize our understanding of wood structure and its biodegradation. Light (bright field, optical, fluorescence, ultraviolet) microscopy remains the dominant type of wood analysis allowing for global and detailed information of native cellular structure and chemistry as well as degraded wood. Light and electron microscopy (scanning and transmission) techniques provide complementary information from global through tissue, cell, subcellular, and sub-organelle levels with high spatial resolution not available using other approaches. Conventional scanning and transmission electron microscopy (SEM/TEM) and ancillary approaches (FE-SEM, ESEM, Cryo-SEM, Cryo-TEM, SEM-EDX, TEM-EDX, and rapid freezing approaches) have greatly improved our finite understanding of the structure of wood cell walls and polymers and of the different morphological forms of wood decay described from light microscopy. SEM and FE-SEM have allowed for the three-dimensional structure of wood to be explored and the intimate nanostructure of the microfibrils and microfibril aggregates within cell wall layers to be revealed as well as providing new details on the interaction of microbes and their mechanisms of decay. The advent of electron tomography techniques with FE-TEM should provide intimate high resolution three-dimensional imaging of wood ultrastructure and decay not possible previously. Additional imaging and analysis techniques that have been used to reveal aspects of wood (ultra)structure and chemistry (e.g., FTIR, Raman, XPS, ToF-SIMS, AFM, X-ray microtomography) continue to be developed and applied although the various light and electron microscopy approaches still remain the most widely used and influential. In this chapter an outline will be given on the main microscopy techniques applied for studies on wood (ultra)structure and wood decay with examples and limitations. Emphasis will also be given to sample preparation as this is a fundamental prerequisite for achieving optimal results with all microscopy approaches.
Cellulase production was studied after cultivation of Alternaria sp. MS28 in cellulose containing media. This fungus produces different component activities of cellulases, a property influenced by growth temperature. The data indicates that the production of cellulases is a genetically regulated process in the Alternaria sp. MS28, where endoglucanase production was triggered in the presence of CMC; β-glucosidase production by salicin; however, the presence of glucose suppressed the cellulase production. The growth and cellulase production kinetics revealed that the production of endoglucanase and β-glucosidase started in early log-phase and attained its peak in stationary phase. The higher rates of biomass production and shorter generation time were noted in SDB. The rate of endoglucanase and β-glucosidase production was higher in CMC and salicin containing medium, respectively. Partial characterization of cellulases in cell-free culture supernatant showed that endoglucanase has its optimum activity at 50°C and pH 6.0; while β-glucosidase at 45°C and pH 4.5. The melting temperature for endoglucanase and β-glucosidase were 57° and 59°C, respectively. Activity of both the enzymes was slightly affected by the presence of EDTA indicating that these enzymes may not require divalent metallic ions for their activity.
The properties of wood can be improved through steam-heat treatment. There are many studies about mechanical properties of steam-heat treated wood, but very few studies are on the aspects of chemical modifications. In this study, FT-IR spectra combined with SD-IR spectra, correlation coefficients and 2D-IR spectra are employed to analyze the chemical modifications of teak (Tectona grandis L.F.) wood during steam-heat treatment under treatment temperatures from 120 °C to 220 °C at intervals of 20 °C. Acetic acid, which is produced during steam-heat treatment, acts as a catalyst of condensation and degradation reactions of wood components. The changes of wood components are more and more intense with increasing the treatment temperature. The sensitivity of wood samples to thermal perturbation rises initially with increasing treatment temperature before falling back. The steam-heat treated wood under 180 °C is the most sensitive.
This study evaluated biological resistance of composites produced from polypropylene and either wood or bamboo by using two different levels of particle content and three different particle sizes. Composite specimens containing higher particle content and smaller particle size resulted in increased mass losses in decay resistance tests against Tyromyces palustris, a standardized test fungus, Schizophyllum commune, and Pycnoporus coccineus. As particle content increased, mass losses in laboratory termite resistance tests increased; however, decreased particle size caused slightly decreased mass losses. Higher mass losses in bamboo-composites were obtained compared to mass losses in wood-composites in biological resistance tests. There is no significant effect of particle size on water absorption and thickness swell. The IR spectrums of composite specimens showed that significant changes were seen in the wood components following the application of heat during the manufacturing process. While the IR spectrum of WPC specimens with 70% wood was similar to the wood, the composite specimen with 50% wood displayed similarities to polypropylene.
Easter red cedar (Juniperus virginiana) is a valuable source of heartwood extractives that provide decay resistance against termites and wood decay fungi. This study sought to determine the antifungal activity of heartwood extracts obtained using solvents with increasing polarity (hexane, chloroform, ethyl acetate, and methanol) against two wood decay fungi. The heartwood was extracted with methanol, and the methanol extract was sequentially extracted with hexane, chloroform, and ethyl acetate. The yield of the methanol extractives was 5.26 percent based on dry wood and the percentages of the hexane, chloroform, and ethyl acetate soluble fractions from the methanol extract were 46.4, 8.3, and 28.7 percent, respectively. Hexane and chloroform soluble fractions showed a high inhibitory effect on the growth of the wood decay fungi Trametes versicolor and Gloeophyllum trabeum. Gas chromatography-mass spectrometry analysis identified skeletons of sesquiterpenes and sesquiterpene alcohols in both extracts and the most abundant compounds identified, cedrol, cedrenes, and thujopsenes, were individually screened for antifungal activity. Among the three major sesquiterpenes, cedrol and thujopsene showed the highest inhibitory effects against G. trabeum and T. versicolor, respectively.
Different wood species can be expected to affect the properties of wood—polymer composites (WPCs) differently, as they have different chemical compositions. The chemical composition (cellulose, lignin, hot water, and ethanol/ cyclohexane extractive contents) of acacia, eucalyptus, pine, and oak and the morphological properties such as wood fiber length distribution were determined in order to investigate this effect. Composites of linear low-density polyethylene and 10 wt% of each of the wood species were prepared, using polyvinyl alcohol-co-ethylene as a compatibilizer. Significant differences were found between the wood species in terms of both chemical composition and wood fiber length distribution. These affected the properties of the WPCs in different ways. Use of acacia resulted in a WPC with superior mechanical properties and thermal stability compared with the other species, due to its higher cellulose and lignin contents and a favorable wood fiber length distribution; however, acacia composites also showed a higher water absorption rate due to the higher cellulose content. We also found that WPCs containing wood species with a high lignin and extractive content, such as acacia and oak, had a higher resistance to UV degradation.
Aminosilane, melamine and acetic anhydride treated wood flour were added to polyvinyl chloride (PVC) and manufactured into wood-plastic composites (WPC) panels in order to investigate the influence of modification on the resistance to basidiomycetes of the composite. The composite consisted of 50 wt% wood and 50 wt% PVC dry blend. White rot (Trametes versicolor) and brown rot (Coniophora puteana) fungi were used to inoculate the composite. Test procedure was carried out according to ENV 12038 with an additional water pre-treatment of the composite. All tested formulations showed high resistance to basidiomycetes under the test conditions. With regard to the modifications used, only aminosilane treated composites showed slightly decreased weight loss values compared to the untreated reference.
The biorefinery is an important approach for the current needs of energy and chemical building blocks for a diverse range of applications, that gradually may replace current dependence on fossil-fuel resources. Among other primary renewable building blocks, 5-hydroxymethylfurfural (HMF) is considered an important intermediate due to its rich chemistry and potential availability from carbohydrates such as fructose, glucose, sucrose, cellulose and inulin. In recent years, considerable efforts have been made on the transformation of carbohydrates into HMF. In this critical review we provide an overview of the effects of HMF on microorganisms and humans, HMF production and functional group transformations of HMF to relevant target molecules by taking advantage of the primary hydroxyl, aldehyde and furan functionalities.
The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of vanillin against Listeria monocytogenes Scott A and Escherichia coli O157:H7 was determined in tripticase soy broth (TSB), pH 7 and 6, incubated at 35 °C/24 h and in semi-skim milk incubated
at 35 °C/24 h and 7 °C/14 days. The influence of the fat content of milk on the antimicrobial activity of vanillin was tested
in whole and skim milk incubated at 7 °C/14 days. Mixtures of clove and cinnamon with vanillin were also evaluated in semi
skim milk incubated at 7 °C. The MICs for L. monocytogenes were 3,000 ppm in TSB (pH 7) and 2,800 ppm in TSB (pH 6). The MICs for E. coli O157:H7 were 2,800 ppm in TSB (pH 7) and 2,400 ppm in TSB (pH 6). The MBCs in TSB were 8,000 ppm for L. monocytogenes and 6,000 ppm for E. coli O157:H7. The pH values assayed did not influence significantly the MIC or MBC in TSB. The MICs in semi-skim milk for L. monocytogenes and E. coli O157:H7 were 4,000 and 3,000 ppm at 35 °C/24 h, and 2,500 and 1,000 ppm at 7 °C/7 days, respectively. The MBCs were 20,000 ppm
for L. monocytogenes and 11,000 ppm for E. coli O157:H7. High incubation temperatures did not affect the MBC but increased the MIC of the vanillin in milk. This effect could
be attributed to the increased membrane fluidity and to the membrane perturbing activity of vanillin at low temperatures.
The fat in milk reduced significantly the antimicrobial activity of vanillin, probably due to effect protective of the fat
molecules. Mixtures of clove and cinnamon leaves inhibited the growth of L. monocytogenes in a similar way that vanillin alone but had a synergistic effect on the E. coli O157:H7. Mixtures of cinnamon bark and vanillin had always a synergistic effect and some of the combination assayed showed
bactericidal activity on the population of L. monocytogenes and E. coli O 157:H7.
Summary This study was to isolate and identify the antifungal compounds in the ethyl acetate soluble fraction of the methanol extractives of Taiwania (Taiwania cryptomerioidesHayata) heartwood and to examine their antifungal activity. Five compounds were obtained by open column chromatography and HPLC and based upon the results from Mass, 1 H-NMR, and 13 C-NMR analyses. Their structures were identified, namely ferruginol, helioxanthin, savinin, taiwanin C, and hinokiol. According to the results of antifun- gal test, the order of antifungal index of these compounds for Coriolus versicolor (L. ex Fr.) Quel. was ferruginol > taiwanin C > savinin > hinokiol. For Laetiporus sulphureus (B. ex Fr.) Bond. it was tai- wanin C > savinin > ferruginol > hinokiol.
As a part of wood-plastic composite (WPC) material development, this research evaluated the resistance of WPC formulations to fungal decay and biocide leaching. In laboratory tests using small WPC samples exposed directly to brown-rot and white-rot fungi, there were no weight losses caused by decay in most formulations. Formulations with relatively high wood content and not protected by zinc borate exhibited moderate weight losses. Scanning electron microscopy of WPC specimens supporting fungal growth show mycelium concentrated in the interfacial gaps between the wood and thermoplastic component near the specimen surface. The relative influence of each material component on the WPC resistance to decay was analyzed by simplex analysis. Of the various component term effects, the most influential was that relating to composite wood content. Increases in talc concentration also resulted in greater weight losses. An increase in high-density polyethylene (HDPE) in the formulation reduced susceptibility to weight loss during the accelerated decay test. Zinc borate at 2 percent concentration, the lowest level tested, prevented any weight loss. Our conclusion is that either the inclusion of zinc borate or limiting the wood content of WPC can effectively prevent fungal decay. The very low leach rate as determined by laboratory testing appears to be controlled mainly by dissolution of the zinc borate and not by diffusion. The tests show that zinc borate will take at least 20 years to completely dissolve and leach from the material. Results indicate that careful material design can prevent fungal decay of WPC even under severe exposures.
The dichloromethane extract of the air-dried leaves of Pycnarrhena manillensis afforded stigmast-4-en-3,6-dione (1) and stigmast-4-en-3-one (2) by silica gel chromatography. Their structures were elucidated by extensive 1D and 2D NMR spectroscopy. 1 and 2 exhibited moderate antifungal activity against C. albicans and low antibacterial activity against E. coli and P. aeruginosa. 2 was slightly active against S. aureus, while 1 was inactive against this bacterium. Both compounds were inactive against B. subtilis, T. mentagrophytes and A. niger.
The resistance to fungal attack of wood plastic composites (WPCs) containing 40% polypropylene and 60% either pine, maple or oak, wt%/wt%, was examined. WPCs specimens were made using the hot press system. Resistance to decay was evaluated using soil block and agar tests. Test specimens were exposed to either white-rot fungi, Trametes versicolor or Phanerochaete chrysosporium, or the brown-rot fungi Gloeophyllum trabeum or Postia placenta for six or 12 weeks. Moisture content and weight loss were used to assess the extent of decay of WPCs. Rates of decay in WPCs exposed in soil-block tests were greater than those exposed in the agar. WPCs containing either maple or oak were more susceptible to fungal attack then those containing pine.
Rubber trees were introduced into the Malay Peninsula more than a century ago. The normal economical lifespan of a rubber
tree is about 25 years, and, traditionally, rubberwood was used as firewood by the rural community. In recent decades, rubberwood
has become an important timber for wood products, particularly in the furniture manufacturing sector, due to its attractive
features, cream color, and good working properties. Sapstain, mold, and wooddecaying fungi are serious threats to rubberwood.
Conventional chemical control has been a successful method of preventing staining fungal growth, but the effects of these
chemicals are of concern because they create problems for the environment and public health. Thus, biological control has
been recognized as an alternative approach to the problem. This article reviews the properties, potential utilization, and
problems of protecting rubberwood against sapstain, mold, and wood-decaying fungi, and discusses the treatment methods available.
Advances in biological control, particularly biofungicides, are emphasized as an alternative method for rubberwood treatment.
Key wordsRubberwood–Molds–Preservation
Bamboo is readily infected with fungi because of its abundant sugar, starch and protein content, which greatly restricts its utilization. To develop a highly effective environmentally sound antifungal agent for bamboo, flower-like ZnO microstructures supported on TiO2 thin films have been synthesized on bamboo surfaces by a facile two-step low-temperature hydrothermal method. According to the results of various analytical techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared–attenuated total reflectance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, the bamboo substrate combined with anatase TiO2 by a hydrogen bonding or ligand exchange reaction between F― and –OH. The F― ions on the TiO2 surface combined with [Zn(NH3)4]²⁺ via electrostatic adsorption, contributing to the formation of a flower-like ZnO microstructure, and were then deposited on the TiO2 thin films. Moreover, the antifungal activities of the samples against a hybrid fungi group consisting of Trichoderma viride Pers. ex Fr (T. viride), Penicillium citrinum Thom (P. citrinum), and Aspergillus niger v. Tiegh (A. niger) were investigated during a three-month period under dark conditions. The results showed that pure TiO2 thin films coated on bamboo presented better antifungal activities, with a 21-day inhibition, than that of the pristine bamboo, with a 5-day inhibition. The flower-like ZnO microstructures supported on the TiO2 thin films bamboo exhibited effective antifungal capability, with a 90-day inhibition. The efficient antifungal behavior is due to the increased generation of reactive oxygen species (ROS) from the coatings by a possible synergistic effect between the ZnO and TiO2 nanoparticles in attacking fungi and causing their death.
The main objective of this study was to investigate the algal and fungal resistance of biocide-treated wood flour (WF)/high density polyethylene (HDPE) and bamboo flour (BF)/HDPE composites. The biocides included 4,5-dichloro-2-octyl-isothiazolone (DCOIT), zinc pyrithione (ZPT), and carbendazim (MBC). Resistance to algae and fungi was evaluated by artificially accelerated tests. Treated and untreated samples were exposed to algae (Chlorella vulgaris, Ulothrix sp., Scenedesmus quadricauda, and Oscillatoria sp.) and fungi (Coriolus versicolor and Poria placenta) for 21 days and 12 weeks, respectively. The volatile components of WF and BF extractives were analyzed by gas chromatography-mass spectrometry (GC-MS). The results indicated that incorporation of DCOIT, ZPT, and MBC effectively enhanced the durability of WF/HDPE and BF/HDPE composites against algal and fungal decay. Accordingly, DCOIT, ZPT, and MBC can be used as potential biocides for both WF/HDPE and BF/HDPE composites. GC-MS analysis suggested that palmitic acid, oleic acid, stigmasta-3, 5-dien-7-one, and vanillin in WF possibly provided some resistance to fungal attack, whereas di (2-ethylhexyl) phthalate and linoleic acid in BF were responsible for algal resistance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45148.
Composite materials based on renewable agricultural and biomass feedstocks are increasingly utilized as these products significantly offset the use of fossil fuels and reduce greenhouse gas emissions in comparison with conventional petroleum- based materials. However, the inclusion of natural fibers in polymers introduces several challenges, such as excess water absorption and poor thermal properties, which need to be overcome to produce materials with comparable properties to the conventional composite materials. Instead of using rather expensive chemical and physical modification methods to eliminate these aforementioned challenges, a new trend of utilizing waste, residues, and process by-products in natural fiber-polymer composites (NFPCs) as additives or reinforcements may bring considerable enhancements in the properties of NFPCs in a sustainable and resilient manner. In this paper, the effects of waste materials, residues or process by-products of multiple types on NFPCs are critically reviewed and their potential as NFPC constituents is evaluated.
The in vivo antifungal activity of crude extracts of Dipsacus asper roots was evaluated against the phytopathogenic fungi Botrytis cinerea, Colletotrichum coccodes, Blumeria graminis f. sp. hordei, Magnaporthe grisea, Phytophthora infestans, Puccinia recondita and Rhizoctonia solani using a whole-plant assay method. Ethyl acetate and acetone extracts, at 1000 μg/mL, suppressed the development of tomato gray mold (TGM) and tomato late blight (TLB) by 90%. Through bioassay-guided isolation, five antifungal substances were isolated from the D. asper roots and identified as β-sitosterol (1), campesterol (2), stigmasterol (3), cauloside A (4) and a novel dipsacus saponin, named colchiside (3-O-β-d-xylopyranosyl-23-O-β-d-glucopyranosyl-28-O-β-d-(6-O-acetyl)-glucopyranosyl hederagenin) (5). Of those, cauloside A (4) displayed the greatest antifungal efficacy against rice blast, TGM and TLB. Colchiside (5) moderately suppressed the development of TLB, but exhibited little effect against the other diseases. The synergistic effects of the isolated compounds against TLB were also assessed. Synergistic and additive interactions were observed between several of the sterol compounds. This study indicated that the crude extracts of, and bioactive substances from, the roots of D. asper suppress TGM and TLB. In addition, cauloside A (4) and colchiside (5) could be used as antifungal lead compounds.
Wood samples of Pinus rigida, Juglans nigra, and Fagus sylvatica were superficially inoculated with three mold fungi (Penicillium selerotigenum, Paecilomyces variotii, and Aspergillus niger). The changes in wood surfaces and the elemental composition were observed by scan electron microscope (SEM) and the electron dispersive X-ray spectroscopy (EDX), respectively. Wood elemental composition was an indication of the growth of mold fungi, in which P. selerotigenum, and A. niger have consumed high amount of carbon (C) of F. sylvatica wood compared to control treatment. Also, P. selerotigenum consumed high amount of C of J. nigra wood compared to the control. While, the three mold fungi showed little changes in C content in P. rigida wood. The nitrogen element in the studied woods was completely consumed by the three mold fungi. Cl element increased in the three woods as inoculated by the three fungi compared to untreated woods. Other elements such as S, Si, Ca, Zn, Cu, and Fe varied in their content in accordance to the interaction among wood species and fungi. The growth of the three mold fungi showed distribution and structures of spores and hyphae covering deteriorated wood surfaces. The study suggests that the three mold fungi metabolize the carbon-rich constituents of the investigated wood species in a proportional manner and produce large fruiting structures that release vast numbers of spores in nature.
Brown-rot and white-rot fungi have been found growing on recycled plastic/wood composite lumber after only 4 years in service in Florida.
The ability of natural and synthetic hinokitiol, as well as a water soluble derivative (hinokitiol sodium salt), to protect wood against fungal attack was examined. Synthetic and natural hinokitiol provided similar protection. All three materials exhibited similar antifungal activity against Aspergillus niger and Penicillium citrinum on yellow poplar wafers at concentrations of 1 mg/mL or greater. Fungal attack by Gloeophyllum trabeum or Trametes versicolor was completely inhibited in soil block tests in wood treated with any of the three extracts at concentrations of 20 mg/mL or greater. The water soluble hinokitiol sodium salt was highly susceptible to leaching, and blocks subjected to leaching had little resistance to fungal attack. The results suggest that further formulation development will be necessary to produce a water-soluble hinokitiol system that can resist leaching and retain biological activity.
Background
Hinokiol is a naturally occurring diterpenoid compound isolated from plants such as Taiwania cryptomerioides. Anti-oxidation, anti-cancer, and anti-inflammation effects of this compound have been reported. It is not yet known if hinokiol affects neurons or neuronal ion channel activities. We reported here that hinokiol inhibited voltage-gated Na⁺ channels (VGSC) in neuronal cells and we characterized the mechanisms of block.
Methods
The effects of hinokiol on Na⁺ channels were examined using the voltage-clamp (whole-cell mode) technique.
Results
VGSC was blocked by hinokiol in a concentration-dependent and state-dependent manner in neuroblastoma N2A cells: IC50 are 11.3 and 37.4 μM in holding potentials of −70 and −100 mV, respectively. In the presence of hinokiol there was a 13-mV left shift in steady-state inactivation curves; however, activation gating was not altered. VGSC inhibition by hinokiol did not require channel opening and was thus considered to be closed-channel block. In the presence of hinokiol, since the degree of block did not enhance with stimulation frequency, block by hinokiol thus did not exhibit use-dependence. Recovery from channel inactivation was not significantly affected in the presence of hinokiol. In addition, hinokiol also inhibited VGSC of differentiated neuronal NG108-15 cells and rat hippocampal CA1 neurons.
Conclusion
Our results therefore suggest hinokiol inhibited VGSC in a closed-channel block manner and such inhibition involved intensification of channel inactivation.
The damage in wood is commonly associated with fungi which do not affect wood strength. This study
investigates the in-vitro growth inhibition of Trichoderma harzianum, a well-known fungus, by different
methanol extracts from selected tree species.We observed the hyphal growth by the environmental scan
electron microscope (ESEM) and evaluated the changes in the elemental composition by the electron
dispersive X-ray spectroscopy (EDX). The methanolic extracts of Morus alba heartwood and Maclura
pomifera bark had significant effects (P < 0.001) on the linear growth of T. harzianum. The treated wood
samples of Acacia saligna with the methanolic extract of Cupressus sempervirens wood showed an inhibition
zone against the growth of T. harzianum around the treated wood at the concentrations of 5, 10,
and 20%. However, ESEM and EDX analyses of treated wood demonstrated that the combination of
Paraloid B-72 and the methanolic extract of C. sempervirens wood might be used as a potent biocide
against the mold fungus T. harzianum.
Ferruginol has antifungal activity against wood-rot fungi (basidiomycetes). However, specific research on the antifungal mechanisms of ferruginol is scarce. Two-dimensional gel electrophoresis and fluorescent image analysis were employed to evaluate the differential protein expression of wood-rot fungus Trametes versicolor treated with or without ferruginol. Results from protein identification of tryptic peptides via liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) analyses revealed 17 protein assignments with differential expression. Downregulation of cytoskeleton β-tubulin 3 indicates that ferruginol has potential to be used as a microtubule-disrupting agent. Downregulation of major facilitator superfamily (MFS)-multiple drug resistance (MDR) transporter and peroxiredoxin TSA1 were observed, suggesting reduction in self-defensive capabilities of T. versicolor. In addition, the proteins involved in polypeptide sorting and DNA repair were also downregulated, while heat shock proteins and autophagy-related protein 7 were upregulated. These observations reveal that such cellular dysfunction and damage caused by ferruginol lead to growth inhibition and autophagic cell death of fungi.
The control efficacy of Platycladus orientalis extract against Rhizoctonia sonali Kühn, the causal agent of rice sheath blight, was evaluated by pot experiments under greenhouse conditions, and the antifungal compounds were isolated and identified through antifungal bioassay-guided fractionation using R. sonali as a tested fungus. The results indicate that the extracts from P. orientalis exhibited a significant reduction in the severity of rice sheath blight. The petroleum ether fraction partitioned from the ethanolic crude extract, showing the highest antifungal activity, was further separated, and two diterpenoid compounds with antifungal property, totarol and sclareol, were isolated and identified from the active subfractions. Totarol and sclareol possessed antifungal activity against most of the tested fungal pathogens of cereal crops such as R. solani, R. cerealis and Fusarium graminearum, indicating a similar broad antifungal spectrum. These findings suggest that the P. orientalis extract and its derived active compounds may be promising candidate agents for controlling plant fungal diseases like rice sheath blight.
Owing to its unique characteristics, wood has historically been a valuable and useful natural resource. It is also one of the most important construction materials mankind has ever come across. Wood is at the heart of modern construction owing to its versatility, abundance in nature and environmental friendliness. It comes in thousands of types and has a remarkably diverse range of applications. This chapter discusses the basic features of wood, i.e. chemical composition, growth and structure. Various aspects of wood, crucial to its role as a construction material - i.e. seasoning, preservation and repair - have also been highlighted. The status of wood as a sustainable construction material has been reflected upon with regard to different features such as environmental friendliness, durability, waste disposal and recycling. Towards the end of the chapter, bamboo, a family member of wood, has been discussed in detail in terms of its structure and properties, applications and sustainability.
The objective of this study was to use FT-IR analysis to investigate the chemical composition of aged and un-aged bamboo specimens, with and without node sections, decayed by brown-rot fungi. Specimens were exposed to two brown-rot fungi, Coniophora puteana and Poria placenta, for 8 weeks after which decay was assessed by weight loss and FT-IR spectra analysis. Depending on the bamboo section examined, the aging process reduced decay resistance of specimens. Weight loss (measured as a percentage) decreased from the top to the bottom portion of bamboo culms. The presence of nodes in the specimens increased weight loss caused by P. placenta attack, and caused only a slight increase in weight loss from C puteana attack. Significant chemical changes in bamboo were observed after fungal degradation, as revealed by FT-IR analyses. Consistent with the degradation mechanism of brown-rot fungi, lignin was essentially un-degraded or modified. Both brown-rot fungi caused a sharp decrease in the carbonyl absorption area. Surprisingly, cellulose peaks of degraded specimens were nearly similar to the peaks of control specimens. Aging treatments and biodegradation affected the crystalline structure of bamboo specimens. Poria placenta degraded wood components faster and changed the crystallinity more than C puteana did, in accordance with the weight losses due to decay.
The anti-fungal performance and mechanical–morphological properties of polyvinylchloride (PVC) and wood/polyvinylchloride composites (WPVC) doped with fungicide were studied for the effects of UV-weathering aging (0–32 days) and soil-burial exposure (0–6 months). Hevea brasiliensis Muell (HB) wood was used for producing the WPVC-HB composites and 3-iodopropinyl-N-butylcarbamate (IPBC) was used as a fungicide. Anti-fungal potential was evaluated using the disk diffusion method. It was found that the effects of UV-weathering aging and soil-burial exposure resulted in decreases in the flexural properties and dimensional stability of WPVC-HB composites, but the properties of pure PVC were not affected. Deterioration in the mechanical properties of WPVC-HB by both of the aging effects was slightly diminished by IPBC addition, but the thermal property tended to decrease due to IPBC degradation. FTIR and TGA results showed that UV-weathering had a greater effect on chemical changes of PVC in WPVC composites. Samples UV-aged for 32 days had decreased anti-fungal performance from 81.4 to 28.3%, while the 6-month soil-burial samples decreased from 81.4 to 4.4%. SEM studies showed evidence that addition of IPBC slowed the deterioration of the material properties for both the UV-weathered samples and the soil-burial samples.
Antifungal properties of polyvinylchloride (PVC) and wood/PVC composites (WPVC) were studied with two different fungicides through disk diffusion and dry weight techniques against Aspergillus niger as a testing fungus. Three different types of woods, including Xylia kerrii Craib & Hutch.(XK), Hevea brasiliensis Muell.(HB), and Mangifera indica Linn.(MI), were used. The disk diffusion results revealed that the addition of 3-iodopropinyl-N-butylcarbamate (IPBC) in the PVC and WPVC markedly reduced the diameter of fungi, whereas the addition of methylbenzimidazole-2-ylcarbamate(Carbendazim) did not. The results from IPBC samples by the dry weight technique corresponded to those by the disk diffusion method. Adding fungicides tended to slightly increase the flexural properties of PVC, whereas in the case of WPVC those properties were deteriorated by IPBC and carbendazim additions. The total color change was less when IPBC only was introduced into PVC. FTIR spectra suggested that no chemical structure changes were observed after the addition of IPBC and carbendazim. The higher surface contact angle and fungicide release values for IPBC samples could imply greater diffusibility of IPBC in PVC and WPVC matrices, accompanied by increased antifungal activity. WPVC with HB wood showed the best antifungal performance, at an optimal concentration of 10,000 ppm, when compared with XK and MI woods. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers
Microbial activity in soil is usually limited by the availability of carbon (C). Adding an easily available C source, like glucose, has therefore been a common approach to study alleviation of resource limitations. Most such studies have relied on respiration to study microbial dynamics, with few following the explicit growth response. We determined the response in bacterial and fungal growth, as well as respiration, to additions of glucose (0.5–32 mg C g−1 soil) during up to 6 days, using leucine incorporation for bacterial growth and acetate-in-ergosterol incorporation for fungal growth. A concentration of 2 mg glucose-C g−1 soil, where the fungal contribution appeared to be small, was also studied with a high time resolution. Adding glucose resulted in an initial lag phase of stable respiration and bacterial growth. Bacterial growth was similar to the unamended control, while respiration was 8 fold higher during this period. The 14-h lag phase was followed by an exponential increase for both respiration and bacterial growth, with a similar intrinsic growth rate (μ) of around 0.25 h−1. After the exponential phase, bacterial growth decreased exponentially. The respiration initially decreased even more rapidly than bacterial growth. At concentrations exceeding 4 mg glucose-C g−1 the relative stimulation of fungal growth surpassed that of bacteria, with the highest amendment rates, 32 mg C g−1, resulting in mainly fungal growth. Lower loading rates than 4 mg glucose-C g−1 appeared to stimulate mainly bacterial growth.
The resistance of natural and treated with preservative wood to filamentous (mould) fungi (Ascomycota, Fungi Imperfecti) and the efficacy of fungicides in terms of control of discolourations and disfigurements caused by the fungi growing on the wood surface over a very short time is determined by several, mainly descriptive, laboratory methods, very often using a subjective visual grading base. The aim of the research was to evaluate the growth of filamentous fungi on wood samples by comparing a descriptive method and instrumental methods, to attempt to quantify and objectify the assessment of wood susceptibility to mould fungi using as both an example and a model wood acetylated with acetic anhydride and control wood samples of the same species. For 4 weeks samples of beech (Fagus sylvatica), birch (Betula pendula) and poplar (Populus nigra) wood were exposed to a mixture of pure cultures of: Aspergillus niger, Penicillium funiculosum, Paecilomyces variotii, Trichoderma viride and Alternaria alternata fungi or only to Chaetomium globosum fungus. The growth of fungi on the surface of the test samples was evaluated using descriptive (4-grade accepted scale) and instrumental (total colour changes and ergosterol content measurements) methods. The mean descriptive grade of fungal growth was from 2.3 to 3.0 and the instrumental evaluation of the growth was between 8.1 and 31.0 in terms of total colour change and from 152.3 to 437.5 μg 10 cm−2 of ergosterol content. Measurements of the colour changes of the wood surface and ergosterol content show a greater differentiation of wood infestation grades than the evaluation based on descriptive methods.
Antifungal activity against Botrytis cinerea of lavender, rosemary, peppermint, sweet basil, rose, ginger, and thyme extracts alone at different concentrations (0.04, 0.19, and 0.40 mg/mL) or in combination with vanillin was investigated. Comparatively, 0.04 and 0.19 mg/mL concentrations of essential oil extracts were less inhibitory than that of 0.40 mg/mL concentrations. However, with rosemary extracts, high inhibitory activity was observed for all tested concentrations. On the other hand, the combination of essential oil extracts with vanillin exhibited a marked antifungal activity for B. cinerea with thyme, lavender, and peppermint extracts. These inhibitory effects are interesting in connection with the prevention of gray mold rot in many agricultural products and these antifungals could be used instead of synthetic products.
Moisture sorption and decay resistance of HDPE based wood plastic composites (WPC) made from poplar, Douglas-fir, black locust, white oak, and ponderosa pine were investigated. Dimensional stability of WPC made from poplar was poor while black locust performed extremely well. There were no significant gravimetric differences in composites produced using Douglas-fir, poplar, or pine exposed to Gloeophyllumtrabeum (brown rot). However, Trametesversicolor (white rot) produced significantly higher weight losses on HDPE/poplar composites, while Douglas-fir based WPC were less susceptible to this fungus. FTIR spectroscopy showed that white rot selectively decomposed lignin while brown rot degraded both polysaccharides and lignin. Cellulose and hemicelluloses content decreased in WPC exposed to brown rot. Chitin in the fungi cell walls increase polysaccharide content of decayed WPC. The results suggest that poplar and pine would be the preferred wood species for WPC production for applications where conditions would not be suitable for white rot.
IntroductionPreservatives for Wood LumberMicroorganisms Active in Degradation and Staining of Composite MaterialsMicrobial Infestation of Wood–Plastic Composite MaterialsSensitivity and Resistance of Composite Materials to Microbial Degradation: ExamplesASTM Tests for Microbial Growth and Degradation of Wood–Plastic CompositesEffects of Formulation on Sensitivity and Resistance of Wood–Plastic Composites to Microbial DegradationBiocides Used (Actually or Under Consideration) in Wood–Plastic CompositesBiocides: Accelerated Laboratory Data and the Real WorldReferences
Over the last century, the world has become increasingly dependent on oil as its main source of chemicals and energy. Driven largely by the strong economic growth of India and China, demand for oil is expected to increase significantly in the coming years. This growth in demand, combined with diminishing reserves, will require the development of new, sustainable sources for fuels and bulk chemicals. Biomass is the most attractive alternative feedstock, as it is the only widely available carbon source apart from oil and coal. It was recently found that direct parental administration of SMF to mice leads to abundant acute necrosis and proteinaceous casts in the proximal tubules as the dominating toxicological effect. Additional research provided evidence for the involvement of organic anion transporters in the renal accumulation of SMF. These transport characteristics could be responsible for the selective damage of renal proximal tubules by this reactive metabolite.
We investigated the effects of fiber variability, size, and content on selected mechanical and physical properties of wood plastic composites. HDPE and fibers were compounded into pellets by twin-screw extrusion and test specimens were prepared by injection molding. All tested properties vary significantly with fiber origin. Higher fiber size produces higher strength and elasticity but lower energy to break and elongation. The effect of fiber size on water uptake is minimal. Increasing fiber load improves the strength and stiffness of the composite but decreases elongation and energy to break. Water uptake increases with increasing fiber content.
Rigid PVC/wood-flour composite lumber containing either hardwood (maple) or a softwood (southern pine) wood flour at different levels of wood-flour content was evaluated for susceptibility to fungal colonization and discoloration by using standard tests that mimicked exterior (ASTM G21) and interior (ASTM D3273) environments, respectively. In the exterior test protocol, although both types of PVC/wood-flour composite lumber exhibited fungal colonization and discoloration, the composites containing maple exhibited greater discoloration than those containing pine. Irrespective of wood species, fungal colonization and discoloration in the composite lumber were greater at the bottom faces where they were in constant contact with moisture. The wood content range (50–100 phr) used in this study showed no effect on extent of fungal colonization and discoloration. All composites showed no discoloration in the interior test protocol. Both optical microscopy and environmental scanning electron microscopy clearly demonstrated that wood flour particulates are not completely encapsulated by the PVC matrix, so that exposed wood flour in the surface crevices of the composite lumber may serve as points of moisture sorption and staging points for fungal colonization and discoloration. J. Vinyl Addit. Technol. 10:179–186, 2004. © 2004 Society of Plastics Engineers.
The effect of wood species on the mechanical and thermal properties of wood–plastic composites (WPCs) was explored. Various wood species, including cherry, sweet gum, hickory, yellow poplar, Osage orange, walnut, eastern red cedar, pine, maple, and red oak, were compounded with virgin isotactic polypropylene in a 50 : 50 weight ratio and injection-molded. The tensile strength of WPCs made with cedar and hickory was higher than that of WPCs made with maple, oak, and Osage orange. The tensile modulus of WPCs made with gum and walnut was higher than that of oak WPCs. The tan δ peak temperatures and peak values from dynamic mechanical analysis indicated that pine and hickory WPCs had higher amorphous or void contents than walnut and cherry WPCs. The induction time during isothermal crystallization suggested that red cedar, cherry, and gum WPCs had higher nucleation density than walnut, pine, and oak WPCs. Dynamic mechanical properties of the WPCs appeared to be related to the crystallization behavior of the wood flour, which depends on the surface roughness. Although there were statistically significant differences in mechanical properties among the species, the differences were small, implying that wood flours from many species can be used successfully as raw materials for WPCs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Input of easily available C and N sources increases microbial activity in soil and may induce priming effects (PE)--short-term changes in SOM decomposition after substrate addition. The relationship between the origin of priming and growth characteristics of the microbial community is still unclear. We related real and apparent PEs induced by glucose and N addition with growth strategies of soil microorganisms. Two concentrations of uniformly labeled 14C glucose with and without N were added to Chernozem, and the released 14CO2 and CO2 efflux were monitored over a 300 h period. The shift in strategies after glucose addition was monitored by microbial growth kinetics based on the estimation of maximal specific growth rate. The production of unlabelled extra CO2 induced by glucose was completed after 3 days and amounted to about 15-19% of the microbial biomass-C. The presence of real or apparent PE depended on the level of added C and N. An apparent positive PE was observed when the amount of applied glucose-C was 13 times lower than the amount of microbial biomass-C, i.e. under C-limiting conditions. Apparent PE was accompanied by a higher maximal microbial specific growth rate, i.e. by a shift towards r-strategy features. The absence of a priming effect was observed under N-limiting conditions at an eightfold excess of glucose-C versus microbial biomass-C. A large excess of glucose and N lowered maximal specific growth rates of soil microorganisms and had a negative priming effect. Accordingly, slow-growing microorganisms (K-strategists) switched from SOM mineralization to glucose uptake, probably due to preferential substrate utilization. Analysis of microbial growth kinetics was an efficient approach for evaluating short-term changes in the response of microorganisms to substrate addition; this approach is therefore suitable for assessing transitions between K and r strategies.