Article

Role of heavy metal tolerant rhizosphere bacteria in the phytoremediation of Cu and Pb using Eichhornia crassipes (Mart.) Solms

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

The role of multi-heavy metal tolerant bacteria isolated from the rhizosphere of Eichhornia crassipes in the phytoremediation of Cu and Pb under laboratory conditions was investigated. The heavy metal tolerant rhizosphere bacteria were identified as Bacillus cereus, Paenibacillus alvei, Aeromonas caviae, Paenibacillus taiwanensis, and Achromobacter spanius. Results showed a significant variation in wet weight, Heterotrophic Plate Count (HPC) of the rhizosphere, HPC of water, removal and uptake of Cu and Pb by E. crassipes, either alone or in association with the rhizosphere bacteria. The removal of Cu by E. crassipes in different experimental conditions showed that OTC (Oxytetracycline) untreated E. crassipes with rhizosphere bacteria has maximum removal with 95%, followed by E. crassipes alone with 84%. The OTC treated E. crassipes with rhizosphere bacteria could remove 81% of Cu. The maximum Pb removal efficiency of 93.4% was shown by OTC untreated E. crassipes with rhizosphere bacteria, followed by E. crassipes alone with 86.8%. The OTC treated E. crassipes with rhizosphere bacteria showed the least removal efficiency with 82.32%. The translocation factor (TF) values for Cu and Pb were lower than 1 indicated that the absorption was mainly accomplished in the roots of E. crassipes. The order of accumulation of Cu and Pb in E. crassipes was noted as root > leaf > petiole.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Bacillus lichenformis was reported to have enhanced the accumulation of Cu, Cd, Pb, and Cr [27]. In addition, a recent study by Kabeer et al. [28] reported a reduced shoot content of Cu and Pb upon treatment with rhizobacteria, while Schwabe et al. [14] reported an increased shoot content of Ge and REEs upon inoculation with PGPR. ...
Article
Full-text available
Bioaugmentation promises benefits for agricultural production as well as for remediation and phytomining approaches. Thus, this study investigated the effect of soil inoculation with the commercially available product RhizoVital®42, which contains Bacillus amyloliquefaciens FZB42, on nutrient uptake and plant biomass production as well as on the phytoaccumulation of potentially toxic elements, germanium, and rare earth elements (REEs). Zea mays and Fagopyrum esculentum were selected as model plants, and after harvest, the element uptake was compared between plants grown on inoculated versus reference soil. The results indicate an enrichment of B. amyloliquefaciens in inoculated soils as well as no significant impact on the inherent bacterial community composition. For F. esculentum, inoculation increased the accumulation of most nutrients and As, Cu, Pb, Co, and REEs (significant for Ca, Cu, and Co with 40%, 2042%, and 383%, respectively), while it slightly decreased the uptake of Ge, Cr, and Fe. For Z. mays, soil inoculation decreased the accumulation of Cr, Pb, Co, Ge, and REEs (significant for Co with 57%) but showed an insignificant increased uptake of Cu, As, and nutrient elements. Summarily, the results suggest that bioaugmentation with B. amyloliquefaciens is safe and has the potential to enhance/reduce the phytoaccumulation of some elements and the effects of inoculation are plant specific.
Article
Heavy metals, a treasure of nature, turns to be toxic at high concentrations in water. Among several methods adopted to alleviate heavy metal pollution, bioremediation is considered to be a sustainable, cost-effective technology. Bioremediation largely relies on bacteria, apart from other microbes and plants. The inherent and adaptive mechanisms evolved in bacteria to defend the metal toxicity include bioadsorption/biosorption, bioaccumulation, bioprecipitation and bioleaching. Heavy metal resistant bacterial strains are easy to culture and maintain, and even dead cell biomass display high heavy metal remediation potential in solution. All the heavy metal remediation mechanisms exhibited by bacteria in water is comprehensively reviewed with recent research outputs and in-situ and ex-situ techniques. The cellular mechanisms of heavy metal remediation are discussed, considering efficient bacterial strains, physiochemical parameters, nutrient supplementation and design of novel microbial techniques. Research at omics level would effectuate further manipulation of the cellular process and increase its efficiency. Bacterial heavy metal remediation technique provides double benefit of metal recovery and water purification, along with reuse prospects for both water and metal resources. Technological intervention could meet the challenges of process acceleration, resist biofouling, compete with native wild bacterial species in wastewater, design for commercialization. Industrial translation of the technology is the pivotal avenue to be tackled. Ultimately, understanding of bacterial heavy metal remediation process is essential for the implementation of this promising technology to safeguard the environmental health.
Article
Full-text available
The current research was carried out to estimate the potential of water hyacinth (WH) for removal of nine heavy metals (HMs) from three irrigation canals in Nile Delta. Sampling was achieved in monospecific and homogeneous WH stands at three irrigation canals in the study area, and WH biomass was sampled at monthly intervals from April 2014 to November 2014 using five randomly distributed quadrats (each 0.5 × 0.5 m) at each canal. All HM concentrations were significantly higher in the roots compared with the other WH organs. The WH was recognized by a bioaccumulation factor >1.0 for all HMs. The WH was recognized by translocation factor <1.0 for all HMs (except Pb). In many cases, the concentrations of the HMs in the different organs of WH were correlated with the same HMs in the water. Such correlations indicate that WH reflects the cumulative influences of environmental pollution from the water, and thereby suggesting its potential use in the bio-monitoring of most examined HMs. In conclusion, WH is a promising macrophyte for remediation of irrigation canals polluted with Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn.
Article
Full-text available
The water pollution impacts on water quality degradation and the population of E. crassipes covered almost 30% in Batujai Reservoir area. Among pollutants, heavy metals are one that should be highlighted because they are non-biodegradable, accumulate in the environment, and has been considered as a vital threat to the human health via the food chain. E. crassipes is to be a promising candidate for pollutant removal because of rapid growth rate and extensive root system. The purpose of this research is to know the bioaccumulation of heavy metals by E. crassipes in Batujai Reservoir, Central Lombok Regency. The water hyacinth was maintained by the mesocosm approach at 5 sites in Batujae Reservoir. The results showed that the concentration of Pb in the water was higher among other heavy metals, it was ranged from 0.14 to 0.24 g mL⁻¹, and has exceeded the drinking-water quality standard of 0.03 g mL⁻¹ of the Government Regulation of Indonesia No. 82/2001 and 0.01 g mL⁻¹ recommended by WHO. The values of the bioaccumulation factor (BAF) Pb in the root of E. crassipes has increased at five sampling sites when exposure times were increased. The highest values of BAF Pb in E. crassipes was found in the fish cultivation area (S1) on the 6th week (42.11) and the lowest BAF Pb values in E. crassipes were found in inlet area (S3) on the 2nd week (19.74). The average value of BAF Pb by the root of E. crassipes in exposure time for 42 days on the five sampling sites in Batujai Reservoir was 33.83. Based on the BAF value, E. crassipes is a good bioaccumulator for Pb.
Article
Full-text available
Phytoremediation is a cost effective and eco-friendly process to remove heavy metals from water. A small scale experiment was conducted to determine the phytoremediation efficiency of two macrophytes i.e.: P. stratiotes and E. crassipes for the removal of chromium and copper from the prepared metal solutions of different concentrations (2, 4, 6, 8 mg/L) for a period of one month. Both aquatic macrophytes showed different efficiency for the removal and accumulation of Cr and Cu. The dry biomass of both macrophytes increased over the period of time. The average accumulation of chromium in roots and leaves of P. stratiotes was 85 mg, 56 mg and copper was 96 mg and 70 mg respectively whereas the average accumulation of chromium in roots and leaves of E. crassipes was 90 mg, 53 mg and copper was 86 mg, 50 mg respectively. Higher absorbance of metals were observed in roots as compared to the leaves of both macrophytes. The concentration of metals in the solution significantly decreased from day 1 to day 30. The results of one-way ANOVA showed that removal of chromium was significantly (p < 0.05) greater in E. crassipes and removal of copper was significantly (p < 0.05) greater in P. stratiotes.
Article
Full-text available
Heavy metals are a noxious form of pollutants present in soil and water. A new plant-based solar energy driven technology, phytoremediation, emerges as eco-friendly and cost-effective approach to remove heavy metal from various media with the help of hyperaccumulating plant species. This review paper aims to provide information on phytoremediation and its mechanisms for heavy metal removal especially to focus on Cadmium (Cd) metal and highlights the role of various hyperaccumulating plants for Cd metal remediation in soil and water. It complies various field case studies which play the important role in understanding the Cd removal through various plants. Additionally, it pinpoints several sources and the effects of Cd and other technologies used for Cd remediation. This paper provides the recent development in mechanisms of Cd hyperaccumulation by different plants, in order to motivate further research in this field.
Article
Full-text available
Microbes resistant to heavy metals develop mechanisms to accumulate Cd(II) in their cells. Two bacterial strains, Bacillus cereus AVP12 and B. cereus NC7401 which grew at high Cd(II) concentration were isolated from roots of Tagetes minuta L. growing in Cd(II) contaminated and uncontaminated soil. Minimum inhibitory concentration (MIC) and percent removal capacity were determined as function of pH, contact time and initial Cd(II) concentration. Bioaccumulation capacity was determined to observe possible effect of two different rhizospheres on Cd(II) removal capacity of both strains. Both strains were resistant up to 300 mg/l Cd(II) concentration. The percent removal capacity of both strains was maximum at pH 7 and incubation time of 24 hrs. High bioaccumulation capacity was observed with increasing Cd(II) concentration. Both Langmuir and Freundlich models fitted well to data of Cd(II) bioaccumulation. Though, maximum adsorption capacity (Qo) was observed for strains isolated from both types of rhizospheres, however remarkable Qo values of 434.0 and 212.7 mg/g were observed for Bacillus cereus AVP12 and NC7401, respectively isolated from polluted rhizosphere. Bacillus cereus strains growing in polluted rhizosphere can develop high Cd(II) uptake ability in comparison to non-polluted rhizosphere.
Article
Full-text available
The soil contamination is brought on by the undesirable inputs of different inorganic and in addition natural contaminations having an unfavourable impact on vegetation and on living life forms. The significant impact of contamination is limited supply of vital supplements needed for fitting development of plants. Present study was led to investigate the diverse types of Datura stramonium, Cannabis sativa, Saccharum spontaneum, Ricinus communis and Cana indica that survive under these antagonistic conditions associated with certain group of mycorrhizal species. The development of specific plant in contaminated region is backed by numerous rhizobacteria and mycorrhiza which gives macro or micro supplements. In this study mycorrhiza has been investigated from the rhizosphere of Datura stramonium, Cannabis sativa ,Saccharum spontaneum, Ricinus communis and Cana indica which helps the plant to confine the deadly impacts of contaminations. Soil samples were gathered from different contaminated locales and various techniques were used to isolate mycorrhizal spores from soil and quantify the external hyphae of arbuscular fungi. Also root of the plants collected from these areas were checked for mycorrhizal association inside the roots and been discovered to be fundamentally associated with mycorrhiza specifically Glomus ,Acaulospora and Scutellospora sp. After checking the root colonization, more noteworthy colonization in plants clearly indicates the essential part of mycorrhiza for the existence of Datura in these contaminated locales. Keywords: Soil pollution, arbuscular mycorrhiza, root colonization, rhizosphere.
Article
Full-text available
In this study, we investigated the effects of different lead (Pb) concentrations (0, 200, 600, 1000, 1400 mg kg⁻¹ soil) on the growth, ion enrichment in the tissues, photosynthetic and physiological characteristics, and cellular structures of privet seedlings. We observed that with the increase in the concentrations of Pb, the growth of privet seedlings was restricted, and the level of Pb ion increased in the roots, stem, and leaves of the seedlings; however, most of the ions were concentrated in the roots. Moreover, a decreasing trend was observed for chlorophyll a, chlorophyll b, total chlorophyll, net photosynthesis (Pn), transpiration rate (Tr), stomatal conductance (Gs), sub-stomatal CO2 concentration (Ci), maximal photochemical efficiency (Fv/Fm), photochemical quenching (qP), and quantum efficiency of photosystem II (ΦPSII). In contrast, the carotene levels, minimum fluorescence (F0), and non-photochemical quenching (qN) showed an increasing trend. Under Pb stress, the chloroplasts were swollen and deformed, and the thylakoid lamellae were gradually expanded, resulting in separation from the cell wall and eventual shrinkage of the nucleus. Using multiple linear regression analysis, we found that the content of Pb in the leaves exerted the maximum effect on the seedling growth. We observed that the decrease in photosynthetic activation energy, increase in pressure because of the excess activation energy, and decrease in the transpiration rate could result in maximum effect on the photosynthetic abilities of the seedlings under Pb stress. Our results should help in better understanding of the effects of heavy metals on plants and in assessing their potential for use in bioremediation.
Article
Full-text available
nal homepage: http://www.ijcmas.com Rhizoremediation is an in-situ remediation approach involving microorganisms for the biodegradation of organic pollutants and various other contaminants in the root zone. Plant roots provide a rich niche for the microorganisms to grow at the expense of the root exudates and in turn microbes act as biocatalysts to remove the pollutants. The harmful pollutants such as: polycyclic aromatic hydrocarbons (PAHs)- pesticides, herbicides etc. are converted to degradable compounds, while heavy metals such as zinc, copper, lead, tin, cadmium etc. are transformed from one oxidation state or organic complex to another. Various mechanisms employed are: producing bio-surfactants which are amphiphilic molecules that form spherical or lamellar micelles, thereby solubilizing hydrophobic contaminants in their core and enhancing their bacterial degradation to simple harmless compounds, producing metal chelating siderophores for heavy metal acquisition, increased humification, biofilm production, acid production etc. The process is affected by variouschemical, physical, biological factors i temperature, pH, soil conditions, nature of the pollutant, indigenous microflora etc. Plant -bacteria interactions play a key role in the process and are characterized by: Colonization of the roots by bacteria, maintenance of the catabolic activity and effect of the external environment conditions on the interaction. Technological advancements and increased insight into sequencing techniques can make rhizoremediation a promising and fertile future technology.
Article
Full-text available
Different factors can influence the absorption and storage of substances in plant biomass. In this study, we evaluated the effect of copper concentration in growth medium and plant exposure time on copper accumulation in Eichhornia crassipes (Mart.) Solms. (Pontederiaceae) roots and leaves under controlled conditions. Plants were subjected to four treatments of copper concentrations of 1, 3 and 5 μg.mL-1 , with a control treatment of 0 μg.mL-1 , and evaluated at seven-day intervals over 21 days. Copper concentration in biomass was analysed by atomic absorption spectroscopy with flame atomisation. The results showed that copper concentration in the growth medium and time of exposure had a significant effect on the amount of copper accumulated by E. crassipes roots and leaves, with roots more efficient compared to leaves. It is likely that E. crassipes has mechanisms for the translocation of metal from the root system to the leaves. Symptoms of copper toxicity were observed in the vegetative parts of the plants at the end of the experiments. This study demonstrates that E. crassipes presents great potential in the absorption and accumulation of copper under laboratory conditions, indicating its effectiveness for applications in phytoremediation processes.
Article
Full-text available
p>Phytoremediation is a bioremediation process using plants and microorganisms to extract, sequester, or detoxify heavy metals. Eichhornia crassipes [(Mart.) Solms] is a well-known phytoremediating plant that has the ability to remove heavy metals from water by accumulating them in their tissues. Acinetobacter sp. IrC1 and Acinetobacter sp. IrC2 are copper resistant bacteria isolated from industrial waste in Rungkut, Surabaya. The aim of this research was to study the effect of Acinetobacter sp. IrC1 and Acinetobacter sp. IrC2 inoculation in copper phytoremediation process using Eichhornia crassipes . Bacterial isolate with colony form unit of 10<sup>8 </sup>was inoculated into the rhizosphere of Eichhornia crassipes in water containing 10 mL · L<sup>–1 </sup>and 20 mL · L<sup>–1</sup> copper. Copper removal in contaminated water and copper accumulation in the plant roots was analyzed using atomic absorption spectrophotometer. The results showed that inoculation treatment enhanced the potency of the plant to reduce copper from 94 % concentration level in the medium without bacterial inoculation to 98.3 % and 97 % in medium inoculated with Acinetobacter sp. IrC1 and Acinetobacter sp. IrC2, respectively. Eichhornia crassipes inoculated with Acinetobacter sp. IrC1 accumulated up to six fold higher copper concentrations in roots compared with un-inoculated controls. The roots of Eichhornia crassipes accumulated 596 mg · kg<sup>–1</sup>and 391 mg · kg<sup>–1</sup> in medium containing 5 mL · L<sup>–1</sup> and 10 mL · L<sup>–1</sup> copper without inoculation, while, the upper part of the plants accumulated up to 353 2.5 mg · kg<sup>–1</sup> and 194 1.5 mg · kg<sup>–1</sup> in medium inoculated with Acinetobacter sp. IrC1, respectively. The findings of the study indicated that Acinetobacter sp. IrC1 and Acinetobacter sp. IrC2 can improve the phytoremediation potential of Eichhornia crassipes .</p
Article
Full-text available
Bioremediation means using biological agents to clean environment. Heavy metal pollution being the core all over the word needs immediate attention so that our degrading environments will be remediated. Phytoremediation is an ecofriendly that has shown promising results for the contaminants like heavy metals. The basic fundamental elements in phytoremediation are plants whether terrestrial or aquatic which play key role for remediation of heavy metal affected environments. Phytoremediation has also been a solution for various emerging problems.
Article
Full-text available
Tannery effluent characterization and removal efficiency of Chromium (Cr) and Copper (Cu) on water hyacinth has been observed by filtration process. The effluent was contaminated by deep blue color, acidic pH, higher value of total dissolve solid (TDS), electrical conductivity (EC), chemical oxygen demand (COD) and lower value of dissolve oxygen (DO). After filtration, the effluent shows that the permissible limit of investigated metals. Adsorbent capacity of water hyacinth shoot powder for Cr and Cu ion was found to be 99.98% and 99.96% for standard solution (SS) and 98.83% and 99.59% for tannery effluent (TE), respectively.
Article
Full-text available
The objective of this study was to assess the impact of metal contamination on microbial functional diversity and enzyme activity in forest soils. This study involved the evaluation of the influence of the texture, carbon content and distance to the source of contamination on the change in soil microbial activity, which did not investigate in previous studies. The study area is located in southern Poland near the city of Olkusz around the flotation sedimentation pond of lead and zinc at the Mining and Metallurgical Company “ZGH Bolesław, Inc.”. The central point of the study area was selected as the middle part of the sedimentation pond. The experiment was conducted over a regular 500 × 500-m grid, where 33 sampling points were established. Contents of organic carbon and trace elements (Zn, Pb and Cd), pH and soil texture were investigated. The study included the determination of dehydrogenase and urease activities and microbial functional diversity evaluation based on the community-level physiological profiling approach by Biolog EcoPlate. The greatest reduction in the dehydrogenase and urease activities was observed in light sandy soils with Zn content >220 mg · kg⁻¹ and a Pb content > 100 mg · kg⁻¹. Soils with a higher concentration of fine fraction, despite having the greatest concentrations of metals, were characterized by high rates of Biolog®-derived parameters and a lower reduction of enzyme activity.
Article
Full-text available
The waste water at Sukinda chromite mines (SCM) area of Orissa (India) showed high levels of toxic hexavalent chromium (Cr VI). Chromium contaminated mines waste water having potential threats for biotic community in the vicinity. The aim of the present investigation is to develop a suitable phytoremediation technology for the effective removal of toxic hexavalent chromium from mines wastewater. A water hyacinth species Eichhornia crassipes was chosen to remediate the problem of Cr (VI) pollution from waste water. It has been observed that plants were able to remove 99.5% Cr (VI) of the Sukinda chromite mines processed water in 15 days. This aquatic plant not only removed hexavalent Cr, but capable to reduce TDS, BOD, COD and other elements of water also. Large scale experiment was also carried out in 100L SCM water and same removal efficiency was achieved.
Conference Paper
Full-text available
The research aimed to evaluate of lead (Pb) and copper (Cu) absorption using water hyacinth [Eichhornia crassipes (Mart.) Solms] with the enhancement by the EAPR (electro-assisted phytoremediation) method. Lead (Pb) and copper (Cu) was used in this research as a heavy metal model which was remediated for 7 d of wastewater treatment. The application of designed pot-cathode in 2D of electrode configuration was also evaluated for EAPR process. Heavy metal concentration of the plant tissues was measured by flame-AAS (Atomic Absorption Spectrometry). Plant stress was evaluated through chlorophyll concentration. The results showed that the absorption of Pb by water hyacinth on the basis of EAPR process was much lower than that in the phytoremediation due to high precipitation of lead metal in the aquatic plume during the electromigration process. While on the similar process, the absorption of Cu was very high in the plant root. The plants grown under the EAPR system did not show any significantly low of chlorophyll concentration, suggesting higher tolerance of the plant to the heavy metal concentration. Therefore, the plants, even though under stress condition, were still able to maintain a relatively normal level of photosynthetic pigments.
Chapter
Full-text available
Rhisosphere an area of soil surrounding plant roots in which soil’s most reactions takes place. The Rhizosphere word was given by Lorenz Hiltner and it is 1-2 mm wide. Rhizosphere is divided into three zones- endorhizosphere, rhizoplane and ectorhizosphere. The two dynamic properties of soil rhizosphere are root exudates and soil microbes. Root exudates are the chemical compounds that are secreted by roots and act as a source of food for soil microbes and play a pivotal role in soil microbe and plant interaction. These are low and high molecular weight compounds. The root exudates are important for root microbe and root-root communication. The other important aspect of rhizosphere is soil microbes. The soil microbes include bacteria, fungi and actinomycetes. These orgainisms are important for both soil and fungi. The main aspect of this chapter is to give brief information about the underground world and its future perspective is to understand soil microbe and plant interaction for enhancing sustainable agriculture. Studies on gene expression in the rhizosphere and the use of other molecular techniques like m-RNA, Proteomics, labelled root compounds, stable isotope probes and reporter technology will help in exploring underground undiscovered world.
Article
Full-text available
Arbuscular mycorrhizal fungi (AMF) are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species (Funneliformis mosseae and Rhizophagus intraradices) on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree (Robinia pseudoacacia L.) at Pb addition levels of 0, 500, 1000 and 2000 mg kg-1 soil. AMF symbiosis decreased Pb concentrations in the leaves and promoted the accumulation of biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidases (APX) and glutathione peroxidase (GPX) were enhanced, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species (ROS) scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. Our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the phytostabilization efficiency of Pb contaminated soils.
Article
Full-text available
Phytoremediation or green technology is counted among the successful and effective biological contaminated water treatment techniques. Basically, the concept of this green, cost-effective, simple, environmentally nondisruptive method consists in using plants and microbiological processes to reduce contaminants in the ecosystem. Different species from aquatic plants (emerged, free-floating, and submerged) have been studied to mitigate toxic contaminants such as arsenic, cadmium, chromium, copper, lead, mercury, zinc, etc. Arsenic is one of the most severe toxic elements; it is widely distributed in the environment, usually found in combination with chloride, oxygen, sulphur and metal ions as a result of mineral dissolution from sedimentary or volcanic rocks and the dilution of geothermal water. The effluents from both industrial and agricultural sectors are also regarded as sources to contaminate water. From the accumulation point of view, several aquatic plants have been mentioned as good arsenic accumulators and their performance is evaluated using the green technology method. These include Spirodela polyrhiza, Wolffia globosa, Lemna gibba, L. minor, Eichhornia crassipes, Azolla caroliniana, Azolla filiculoides, Azolla pinnata, Ceratophyllum demersum and Pistia stratiotes. The up-to-date information illustrated in this review paper generates knowledge about the ability of some common aquatic plants around the globe to remediate arsenic from contaminated water.
Article
Full-text available
The aim of the present study was to determine levels of zinc, nickel, copper, lead, cobalt and cadmium, in gills, muscle tissue and exoskeleton of the shrimp Penaeus semisulcatus, caught from Jazan, southern Red Sea coast of Saudi Arabia, and to assess whether these metals are within permissible limits for human consumption. The analysis showed that occurrence of heavy metals were in the order Zn > Pb > Cd > Cu > Ni > Co in gills, Zn > Cu > Pb > Cd > Ni > Co in muscles and Zn > Pb > Cu > Ni > Cd > Co in exoskeleton. An overall ranking of average trace metal levels in the analyzed tissues resulted as gills > exoskeleton > muscles for Zn, Pb and Cd and; in case of Ni, Cu and Co the sequence was exoskeleton > muscle > gills. The highest mean Pb, Cd and Zn concentrations (21.33, 6.33 and 24.0 μg g-1 wet weight, respectively) were found in gills samples, but the highest level of Ni, Cu and Co (3.0, 11.67 and 1. 36 μg g-1, respectively) was observed in exoskeleton. The results revealed that the heavy metal concentrations (except Pb and Cd) in the shrimp Penaeus semisulcatus are below the threshold levels associated with the toxicological effects and the regulatory limits. This study is the first on the shrimp Penaeus semisulcatus in this area and data are important as a background for the estimation of the future impact of metal concentrations in this area.
Article
Full-text available
The study involved a laboratory experiment on the use of Pistia stratiotes in the removal of some heavy metals from a stream polluted by waste water from Kaduna Refinery and Petrochemical Company. Water sample was collected from Kaduna Refinery effluent point, Romi up and Romi down. The Bioconcentration (BCF) and Biotranslocation (BTF) Factors of each metal were determined. The experinmental study showed that Pistia stratiotes is a suitable candidate for effective removal of heavy metals (Hg, Cd, Mn, Ag, Pb, Zn) from Romi stream.
Article
Full-text available
A novel aerobic bacterium, designated strain LAM0705T, was isolated from the rhizosphere of Populus alba in the Peking University Third Hospital. Cells of strain LAM0705T were observed to be Gram-stain positive, motile, spore-forming and rod-shaped. The optimal temperature and pH for growth were found to be 30 °C and pH 7.5, respectively. Strain LAM0705T was found to be able to grow in the presence 0–5 % NaCl (w/v) (optimum 1.0 %). The major fatty acids of strain LAM0705T were identified as anteiso-C15:0, C16:0 and iso-C16:0. The dominant polar lipids were found to consist of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The cell wall peptidoglycan of strain LAM0705T was found to contain meso-diaminopimelic acid. The predominant menaquinone was identified as MK-7. The G+C content of genomic DNA was found to be 48 mol% when determined by the T m method. The 16S rRNA gene sequence similarity analysis indicated that strain LAM0705T is closely related to Paenibacillus agaridevorans DSM 1355T and Paenibacillus thailandensis KCTC 13043T with 97.8 and 96.1 % sequence similarity, respectively. The DNA–DNA hybridization value between strain LAM0705T and P. agaridevorans DSM 1355T was 47 ± 0.8 %. On the basis of its phenotypic, phylogenetic and chemotaxonomic characteristics, strain LAM0705T is concluded to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus populi sp. nov. is proposed. The type strain is LAM0705T (=ACCC 06427T = JCM 19843T).
Article
Full-text available
Phytoremediation is a relatively new approach to treat wastewater contaminated by organic and inorganic substances including heavy metals. The effectiveness of two aquatic plants, Centella asiatica and Eichhornia crassipes, were evaluated for their capabilities in removing copper from copper solution. The aim of this study is to determine the potential of these aquatic plants to act as hyperaccumulators. The aquatic plants were put in 8 liters of solution containing 1.5 mg/L, 2.5 mg/L and 5.5 mg/L of copper, for a period of 21 days. Analyses of heavy metals contents were conducted using an Atomic Adsorption Spectrometer. Results showed an increase of copper within the plants' roots and shoots tissues and a decrease of copper concentration in the solution. The maximum removal of copper in the solutions containing Centella asiatica was 99.6 % as compared to 97.3 % in solutions containing Eichhornia crassipes. Centella asiatica accumulated a maximum amount of copper of 1353.0 mg/kg whereas Eichhornia crassipes accumulated 1147.5 mg/kg of copper in their roots. The accumulation of copper of more than 1000 mg/L in plant tissues indicate that both aquatic plants can be considered as hyperaccumulators of copper. Roots tend to accumulate a higher amount of copper than shoots due to translocation process. Significant removal of copper were obtained at p<0.01 for containers containing both aquatic plants, indicating that Centella asiatica and Eichhornia crassipes can be utilized in the phytoremediation method to remove copper from wastewater.
Article
Full-text available
The present investigation was aimed to assess the effect of cadmium chloride on some biochemical parameters and the potential of cadmium uptake of Eichhornia crassipes. The effects of increasing concentrations of cadmium chloride on growth characteristics of E. crassipes including root length, leaf area and biomass production was studied. The root growth of E. crassipes was severely affected at all concentrations of cadmium in the trays where plants were grown and in general it was serially increased. Similar trend was observed in average leaf area with 11.28 cm2 on 12th day in control while with only 7.05 cm2 at 75 ppm concentration. Chlorophyll contents were also observed to be decreased serially with the increasing concentrations of CdCl2. The lowest total chlorophylls were 118.56 mg/100g in comparison with 239.09 mg/100g in control set at the end of treatment. Polyphenol and proline contents were increased indicating the stress conditions due to toxicity of cadmium. Highest polyphenol and proline were 303.27 mg/100g and 8.14 mg/100g respectively at 50 ppm set of the treatment. Moreover, Electrical conductivity and total dissolved solids content of the various dilutions were decreased remarkably after 12 days of treatment. pH of the solution tend to become neutral while increase in turbidity might be related with root exudates and dead organics by the plants growing in the tray whereas decrease in hardness, acidity, sodium and potassium content was observed with increase in concentration. Values for BOD and COD were slightly increased at the end of treatment. Estimation of bioconcentration factor is very much important. It indicates that the species is more favourable to tolerate higher concentrations of heavy metals and also helps a lot in decontamination of the land, water etc. In this study increasing concentration of cadmium showed higher accumulation capacities and may be better treatment option for cadmium by means of phytoremediation
Article
Full-text available
The objective of this study was to assess the growth of water hyacinth (Eichhornia crassipes) and its ability to accumulate Cu from polluted water with high Cu concentrations and a mixture of other contaminants under short-term exposure, in order to use this species for the remediation of highly contaminated sites. Two hydroponic experiments were performed under greenhouse conditions for 7 days. One of them consisted of growing water hyacinth in Hoagland solution supplemented with 15 or 25 mg Cu/L and a control. The other one contained water hyacinth growing in polluted river water supplemented with 15 mg Cu/L and a control. Cu was accumulated principally in roots. The maximum Cu concentration was 23,387.2 mg/kg dw in the treatment of 25 mg Cu/L in Hoagland solution. Cu translocation from roots to leaves was low. The mixture of 15 mg Cu/L with polluted water did not appear to have toxic effects on the water hyacinth. This plant showed a remarkable uptake capacity under elevated Cu concentrations in a mixture of pollutants similar to pure industrial effluents in a short time of exposure. This result has not been reported before, to our knowledge. This species is suitable for phytoremediation of waters subject to discharge of mixed industrial effluents containing elevated Cu concentrations (≥15 mg Cu/L), as well as nutrient-rich domestic wastewaters.
Article
Full-text available
Discharge of industrial effluents in aquatic environments is a serious threat to life due to toxic heavy metals. Plants can be used as cheap phytoremedients in comparison to conventional technologies. The present study was conducted to check the phytoremediation capability of two free-floating plants, i.e., Pistia stratiotes and Eichhornia crassipes, for the removal of heavy metals from steel effluent by using Atomic Absorption Spectrophotometry. P. stratiotes was able to remove some of the heavy metals, showing the highest affinity for Pb and Cu with 70.7% and 66.5% efficiency, respectively, while E. crassipes proved to be the best phytoremediant for polluted water as its efficiency was greatest progressively for Cd, Cu, As, Al and Pb, i.e., 82.8%, 78.6%, 74%, 73% and 73%, respectively. In conclusion, aquatic plants can be a better candidate for phytoextraction from industrial effluents due to cost effectiveness.
Article
Full-text available
Mercury heavy metal pollution has become an important environmental problem worldwide. Accumulation of mercury ions by plants may disrupt many cellular functions and block normal growth and development. To assess mercury heavy metal toxicity, we performed an experiment focusing on the responses of Eichhornia crassipes to mercury-induced oxidative stress. E. crassipes seedlings were exposed to varying concentrations of mercury to investigate the level of mercury ions accumulation, changes in growth patterns, antioxidant defense mechanisms, and DNA damage under hydroponics system. Results showed that plant growth rate was significantly inhibited (52 %) at 50 mg/L treatment. Accumulation of mercury ion level were 1.99 mg/g dry weight, 1.74 mg/g dry weight, and 1.39 mg/g dry weight in root, leaf, and petiole tissues, respectively. There was a decreasing trend for chlorophyll a, b, and carotenoids with increasing the concentration of mercury ions. Both the ascorbate peroxidase and malondialdehyde contents showed increased trend in leaves and roots up to 30 mg/L mercury treatment and slightly decreased at the higher concentrations. There was a positive correlation between heavy metal dose and superoxide dismutase, catalase, and peroxidase antioxidative enzyme activities which could be used as biomarkers to monitor pollution in E. crassipes. Due to heavy metal stress, some of the normal DNA bands were disappeared and additional bands were amplified compared to the control in the random amplified polymorphic DNA (RAPD) profile. Random amplified polymorphic DNA results indicated that genomic template stability was significantly affected by mercury heavy metal treatment. We concluded that DNA changes determined by random amplified polymorphic DNA assay evolved a useful molecular marker for detection of genotoxic effects of mercury heavy metal contamination in plant species.
Article
Full-text available
Alappuzha district, Kerala state, India has a wide network of rivers, canals, backwaters and most of the water resources are highly contaminated due to the disposal of organic waste, fertilizer residues and run offs from agricultural fields into water bodies. As a result of this water bodies have become a congenial breeding ground for water borne vectors like mosquitoes and pathogenic microorganisms. Availability of safe drinking water is also a serious concern and water borne diseases constitute one of the major public health hazards in this region. In the present study, water samples from (rhizosphere region of aquatic weed, Eichhornia crassipes) five different locations of Cherthala taluk were collected and performed a comparative study on the microbial population and for the presence of E. coli, Vibrio cholerae, Vibrio parahaemolyticus and Salmonella typhi. All the water samples were found contaminated with E. coli, V. cholera and S. typhi. Vibrio parahaemolyticus was found only in three samples. It was also observed that these pathogenic microbes were present very near to the rhizosphere region of E. crassipes. The presence of amino acids glutamic acid, hydroxyl proline, leucine and threonine were found from the rhizosphere regions and these amino acids attracted the pathogenic microbes towards E. crassipes.
Article
Full-text available
Paenibacilli, the Gram positive, aerobic spore bearing bacilli are found normally in the environment. Though these organisms were not known to cause human disease, until recently; few species of this genus have been reported to cause infections in humans. We report here, a case of urinary tract infection in a 60-year-old chronic kidney disease patient due to this rare bacterium. The patient presented with complains of fever, dysuria, and flank pain. Routine and microscopic examination of urine revealed no abnormality except plenty of pus cells and albumin (1+). Bacterial culture showed significant bacteruria and the isolated bacteria was identified to be Paenibacillus alvei based on standard biochemical reactions.
Article
Full-text available
A novel nitrogen-fixing bacterium, BJ-18T, was isolated from wheat rhizosphere soil. Strain BJ-18T was observed to be Gram-positive, facultatively anaerobic, motile and rod-shaped (0.4–0.9 μm × 2.0–2.9 μm). Phylogenetic analysis based on a partial nifH gene sequence and an assay for nitrogenase activity showed its nitrogen-fixing capacity. Phylogenetic analysis based on full 16S rRNA gene sequences suggested that strain BJ-18T is a member of the genus Paenibacillus. High similarity of 16S rRNA gene sequence was found between BJ-18T and Paenibacillus peoriae DSM 8320T (99.05 %), Paenibacillus jamilae DSM 13815T (98.86 %), Paenibacillus brasiliensis DSM 13188T (98.55 %), Paenibacillus polymyxa DSM 36T (98.74 %), Paenibacillus terrae DSM 15891T (97.99 %) and Paenibacillus kribbensis JCM 11465T (97.92 %), whereas the similarity was below 96.0 % between BJ-18T and the other Paenibacillus species. DNA–DNA relatedness between strain BJ-18T and P. peoriae DSM 8320T, P. jamilae DSM 13815T, P. brasiliensis DSM 13188T, P. polymyxa DSM 36T, P. kribbensis JCM 11465T and P. terrae DSM 15891T was determined to be 43.6 ± 2.7, 34.2 ± 5.3, 47.9 ± 6.6, 36.8 ± 3.5, 27.4 ± 4.3 and 23.6 ± 4.1 % respectively. The DNA G+C content of BJ-18T was determined to be 45.8 mol %. The major fatty acid was identified as anteiso-C15:0 (67.1 %). The polar lipids present in strain BJ-18T were identified as diphosphatidylglycerol, phosphatidyl methylethanolamine, phosphatidylethanolamine and phosphatidylglycerol. The phenotypic and genotypic characteristics, and DNA–DNA relatedness data, suggest that BJ-18T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus beijingensis sp. nov. (Type strain BJ-18T=DSM25425T=CGMCC 1.12045T) is proposed.
Article
Full-text available
In a previous study we demonstrated the ability of the rhizobacterium Bacillus cereus AR156 (AR156) to protect tomato against bacterial wilt caused by Ralstonia solanacearum and root-knot disease caused by Meloidogyne incognita. Here, we investigate the ability of AR156 to promote plant growth and its role in the systemic protection of tomatoes cultivated in greenhouses against bacterial speck disease caused by Pseudomonas syringae pv. tomato DC3000 (DC3000). In our experiments, the AR156 population reached 10–10 CFU/g rhizosphere soil, and remained at that level in the rhizosphere of tomato plants for more than 2 months. In terms of its ability to promote plant growth, AR156 increased the average biomass of the tomato by 47.7%. AR156 also elicited induced systemic resistance (ISR) against DC3000, significantly reduced bacterial speck disease severity 1.6-fold, and inhibited proliferation of the pathogen by approximately 15-fold. This strain triggered the accumulation of defence-related genes (PR1 and PIN2) in tomato leaves and primed the leaves for accelerated defence-related gene expression upon challenge with DC3000. That suggested simultaneous activation of the salicylic acid (SA) and the jasmonic acid (JA) dependent signaling pathways by AR156 against DC3000. In conclusion, B. cereus AR156 was found to form robust colonies in the roots of tomato and had some beneficial effects, including biological control of bacterial speck disease via ISR and promotion of plant growth.
Article
Full-text available
Thirty water samples were collected, at two week intervals, from the estuary of the River Coco. The aim was to characterize the presence, distribution and types of Aeromonas spp, in the estuary of the River Coco, Ceara, Brazil (03 degrees 46'28.83''' S e 38 degrees 26'36.52 '' S). Aeromonas were identified in 19 (63%) samples analyzed by plating and CFU counts. Presence/absence tests were positive for 11 (37%) of the samples resulting in the detection of Aeromonas in a total of 23 (77%) of samples. CFU counts varied from < 10 to 1.4 x 10(4) CFU mL(-1). From the isolated strains seven species of Aeromonas were identified: A. caviae (29/69), A. veronii bv. sobria (13/69), A. veronii bv. veronii (8/69), A. trota (6/69), A. media (5/69), A. sobria (4/69) and A. hydrophila and Aeromonas sp. (2/69). Of the 38 strains tested, 23 (60%) showed resistance to at least one of the eight antimicrobials. Multiple resistance to antibiotics was observed in A. caviae, A. media, A. sobria and A. veronii bv. sobria. Aeromonas caviae showed the highest multiple resistance, being resistant to four antibiotics. The presence of those microorganisms may contribute to the occurrence of gastroenteritis, mainly in children, since they are considered opportunists.
Article
Full-text available
Toxic heavy metal pollution of water and soil is a major environmental problem, and most conventional remediation approaches do not provide acceptable solutions. Wetland plants are being used successfully for the phytoremediation of trace elements in natural and constructed wetlands. This study demonstrates the phytoremediation potential of water hyacinth Eichhornia crassipes, for the removal of cadmium (Cd) and zinc (Zn). The phytoaccumulation of heavy metals, Cd and Zn, by water hyacinth E. crassipes, was studied. Water hyacinths were cultured in tap water, which was supplemented with 0.5, 1, 2 and 4 mg/L of Cd and 5, 10, 20, and 40 mg/L of Zn, and were separately harvested after 0, 4, 8 and 12 days. The experiment showed that both Cd and Zn had effects on plant relative growth. Removal of metals from solution was fast especially in the first four days. The accumulation of Cd and Zn in shoots and roots increased with the initial concentration and also with the passage of time. Plants treated with 4 mg/L of Cd accumulated the highest concentration of metal in roots (2044 mg/kg) and shoots (113.2 mg/kg) after 8 days; while those treated with 40 mg/L of Zn accumulated the highest concentration of metal in roots (9652.1 mg/kg) and shoots (1926.7 mg/kg) after 4 days. The maximum values of bioconcentration factor (BCF) for Cd and Zn were 622.3 and 788.9, respectively, suggesting that water hyacinth was a moderate accumulator of Cd and Zn and could be used to treat water contaminated with low Cd and Zn concentrations.
Article
Full-text available
Paenibacillus alvei is known as a secondary invader during European foulbrood of honeybees. Here, we announce the 6.83-Mb draft genome sequence of P. alvei type strain DSM 29. Putative genes encoding an antimicrobial peptide, a binary toxin, a mosquitocidal toxin, alveolysin, and different polyketides and nonribosomal peptides were identified.
Article
Potential bio-agents in context of phyto-technological innovation for removal of heavy metals/metalloids have been tightly linked with amelioration of environmental and human health. The present research investigated the prospective of three wetland plants Pistia stratiotes (water lettuce)Spirodela polyrhiza (a duckweed), and Eichhornia crassipes (water hyacinth)for synchronized multi-metallic removal of six hazardous/non-essential metals (Fe, Cu, Cd, Cr, Zn, Ni)and As (a metalloid)from a Ramsar site of a biodiversity hotspot. Results revealed high removal (>79%)of different metals during 15 days experiment in microcosms. Further, a saturation limit was reached in relation to heavy metals/metalloid removal, and thus it declined after two weeks of phytoremediation experiment in case of water lettuce and water hyacinth (about 8 days saturation limit noticed for duckweed). In the context of phyto-technological efficiency of selected wetland plants, E. crassipes was the most efficient for the removal of selected heavy metals followed by P. stratiotes and S. polyrhiza Significant correlations between metal concentration in remediated water and wetland plants/macrophytes were obtained. Therefore, these wetland plants may be used in devising eco-friendly remediation of hazardous heavy metals from wastewater.
Article
The present study assessed Zn, Cr, Cd, and Pb removal efficiency of Colocasia esculenta, Hydrilla verticillata, Phragmitis australis, Typha latifolia, and Spirodella polyrhiza from sewage-mixed industrial effluent. The fresh/dry weight and relative growth rate of each macrophyte decreased with increasing effluent concentration. H. verticillata and C. esculenta exhibited better growth at 50% effluent over control. The maximum Zn, Cd, and Pb accumulation (1008.23, 28.03, and 483.55 mg/kg dry wt., respectively) was recorded in C. esculenta, whereas Cr (114.48 mg/kg dry wt.) in H. verticillata at 100% effluent. Metal accumulation in roots of all plants species was higher (≥50%) initially with increasing effluent concentration and later transferred to shoots. All plants exhibited BCF >1.0 for all heavy metals, highest being for Zn (91.2) and Cd (75.2) in H. verticillata, for Cr (97.9) and Pb (103) in C. esculenta. Except S. polyrhhiza, all other plants exhibited TF <1.0. Maximum removal efficiency of Zn was 82.8% by H. verticillata, whilst that of Cr, Cd, and Pb by C. esculenta at 50% effluent, demonstrating wide applicability of H. verticillata and C. esculenta for treatment of mixed industrial effluent having heavy metals.
Article
This paper studies bioconcentration of heavy metals in macrophytes. High concentration of heavy metal compounds in the lakes of South Ural is natural. Moreover, some of the South Ural lakes are polluted by heavy metals that get into the water together with partly treated sewage of ferrous and non-ferrous industries as well as mining. The paper analyzes similarities and differences of macrophyte communities in six lakes: Bolshoye Miassovo, Bolshoy Ishkul, Bolshoy Tatkul, Argayash, Savelkul, Baraus. In our research, we determined species diversity for each lake. Potamogeton lucens L. and Lemna minor L. were found in all the studied lakes, and the concentrations of heavy metals were studied in their leaves. Such metals as Fe, Mn, Cu, Zn were found in macrophytes. We obtained a metal ratio Mn <Fe<Cu<Zn in plant leaves. High accumulation of Fe, Cu, Zn was observed in Lemna while Mn accumulates equally. Metals bioconcentration factors (BCFs) were calculated © 2018, Society for Indonesian Biodiversity. All rights reserved.
Article
The present study highlights the prevalence of multidrug resistant bacteria in the rhizosphere of a floating nuisant weed, water hyacinth growing in a tropical wetland of South India. The isolated strains from the rhizosphere were subjected to 16S rRNA gene sequence analysis and identified as Aeromonas taiwanensis and Paenibacillus taiwanensis. The identified strains were tested for the multidrug (13 antibiotics) resistance and pathogenicity. Both A. taiwanensis and P. taiwanensis were found to be multidrug resistant and only A.taiwanensis showed the pathogenicity. The present study is the first report on the prevalence of A. taiwanensis and P. taiwanensis in the rhizosphere of water hyacinth.
Article
The performance of electrically stimulated phytoremediation in the removal of lead, cadmium and copper was assessed in this study. A combination of phyto and electro remediation was attempted in this study for the remediation of the metals from water. Three tanks were setup with different operating conditions for this experiment: control A (only phytoremediation system), control B (only electro remediation) and treatment (combination of phyto and electro remediation). The electrically enhanced phytoremediation system and electro remediation system were operated 2h/day at voltages of 4V for 25 days continuously. In this experiment, the Eichhornia crassipes, an able phyto-remediator exhibited efficient and fast removal of heavy metals from synthetic solution in electro assisted phytoremediation system. The electrically enhanced phytoremediation using aluminum sheet electrodes showed better and effective removal of Cd, Pb and Cu than aluminum rod electrodes. A more favorable and moderate increase of pH was noticed in electrically stimulated phytoremediation system. Eichhornia crassipes has tremendous potential to reduce maximum amount of cadmium (within 15 days), lead (within 15 days) and copper (within 10 days) under electrically stimulated condition. Under electrified condition, maximum amount of Cd and Cu was accumulated in the aerial parts of Eichhornia crassipes but maximum concentration of Pb was attained by roots. This indicates the high heavy metal accumulation capacity of Eichhornia crassipes under electrified conditions. The results showed that 4V voltage is probably suitable to stimulate the Eichhornia crassipes to synthesize more chlorophyll and voltage can improve growth and ability to resist adverse circumstances by promoting chlorophyll synthesis. Eichhornia crassipes stimulated by an electric field has grown better and assimilated more metal. Bioconcentration factor (BCF) an index of hyperaccumulation, indicates that electrically stimulated Eichhornia crassipes is a good hyper accumulator of Cd (BCF = 1118.18) and Cu (BCF = 1152.47) and a moderate accumulator of Pb (BCF = 932.26). Translocation ability (TA) ratio indicates that Eichhornia crassipes have the ability to translocate more amounts of Pb, Cd and Cu to its upper portion under electrified condition. The results imply that the electro-phytoremediation technique seems to be promising in the treatment of wastewater contaminated with heavy metals.
Article
Pig, beef, sheep and turkey fecal specimens were assayed for recovery of inoculated Aeromonas sp. by directly plating the samples on five different agar media. Of these, starch-ampicillin was optimal with respect to selectivity and ability to differentiate from other resident microflora. Generally, the numbers of inoculated Aeromonas sp. recovered on starch-ampicillin agar were similar to those recovered on brain heart infusion and blood ampicillin agar media, and were 101 to 103 greater than the recovery rate on either MacConkey-ampicillin or cefsulodinirgasan-novobiocin agars. The sensitivity for the direct recovery of Aeromonas sp. from inoculated beef feces with naturally contaminating microflora, using streaked starch-ampicillin agar medium, was between 102 and 103 cells per gram. Using starch-ampicillin agar, the incidence of Aeromonas detected from feces of beef, pig, sheep and turkey held at the Beltsville Agricultural Research Center was one of 32, none of 22, none of 24 and three of 21, respectively. Based upon current taxonomic criteria, the isolate from the beef feces had characteristics consistent with both Aeromonas sobria and Aeromonas caviae, whereas three isolates from turkey feces were identified as A. caviae or Aeromonas hydrophila. The organism was isolated from five of five packages of ground beef from retail sources. The discrepancy in the consistent presence of the organism in retail meat suggests that many of the food isolates are probably not of fecal origin.
Article
The present work deals with a promising approach for the removal of heavy metals from secondary treated wastewater using aquatic plants, which are economic and effective in separating metals from polluted water. Since the conventional sewage treatment processes were inefficient to remove heavy metals from wastewater, batch experiments of Phragmites australis, Typha latifolia and P. australis and T. latifolia grown in association and reference (unplanted) were carried out for 15 days of retention time for the removal of copper (Cu), cadmium (Cd), chromium (Cr), nickel (Ni), iron (Fe), lead (Pb), and zinc (Zn) from the secondary treated effluent. Significantly, higher removal of the heavy metals in planted set than the reference revealed role of plants in their removal (analysis of variance, p < 0.05). Higher removal of Cr, Fe, and Zn (66.2 +/- A 3.5, 70.6 +/- A 1.2, and 71.6 +/- A 3.9 %) in the combination of the P. australis and T. latifolia than their individual culture suggested synergistic effect of both the plants in the removal of these metals. Positive relationship was observed between retention time and the removal of heavy metals. Mass balance equation has revealed that the loss of heavy metals in wastewater was equivalent to the net accumulation of heavy metals in plant and loss of heavy metals in natural degradation. P. australis showed higher accumulative capacities for Cu, Cd, Cr, Ni, Fe, and Pb than those of T. latifolia. The P. australis and T. latifolia grown in association might be utilized for the heavy metal removal in the tropical environment.
Article
The present study demonstrated the phytoremediation potential of water hyacinth Eichhornia crassipes, for the removal of copper (Cu) and Cadmium (cd). Young plants of equal size were grown in tap water and supplemented with 0.35, 0.70 and 1.05 mg/L of Cu and 0.27, 0.54 and 0.81 mg/L of Cd individually for 25 days. The experiment showed that both Cu and Cd had effects on plant relative growth. The plant at all the concentrations used in the experiment removed approximately more than 90% of Cu and Cd. Removal of metals from water was fast especially in the first five days. The accumulation of Cu and Cd in roots and stems increased with the initial concentration. At all levels the plants accumulated the highest concentration of Cd in roots, while the highest concentration of Cu was accumulated in stems. The biocencentration factor (BCF) of Cu was higher than that of Cd at the same duration, suggesting that the accumulation potential of Eichhornia crassipes for Cu was higher than that for Cd and could be used to treat waste¬water contaminated with low Cu and Cd accumulations.
Article
The effects of plant species richness on both above- and belowground plant biomass, plant nitrogen (N) pool size, and substrate N concentrations were studied in a full-scale subsurface vertical-flow constructed wetland (CW). Results showed that (i) plant species richness increased belowground plant biomass and its N pool size but had no effect on aboveground plant biomass and its N pool size; (ii) plant species richness increased substrate N removal, especially ammonium N removal; and (iii) plant species richness had no effect on plant N use efficiency, suggesting that the N pool size increased with increasing plant species richness. More N accumulation could be removed through harvesting plant biomass. We concluded that the N removal performance of the CW improved by plant species richness through increasing belowground biomass and relevant N pool size.
Article
We studied the spatial and temporal distribution and abundance of the biocontrol agent Bacillus cereus UW85 in the rhizosphere of soybeans during two growing seasons in the field. For this study, we used a neomycin-resistant mutant, UW85nl, derived from UW85. UW85nl spores were applied to seeds and by 24 h after planting 72% of the spores had germinated. UW85nl colonized emerging radicles, but populations were 10–50-fold smaller on radicles than they were on seeds at planting. UW85nl population sizes in the rhizosphere of 10–35-day old plants were largest near the crown of the plant and smaller further from the crown. For example, in a 1989 experiment 21 days after planting, UW85nl populations were 158-fold larger 0–2 cm below the crown than they were 7–8 cm below the crown. UW85nl population sizes were largest right after planting, and by seed harvest they decreased to levels comparable to indigenous B. cereus populations on untreated roots; however, at harvest the entire B. cereus population on treated roots was neomycin resistant, whereas on untreated roots < 3% was neomycin resistant. The proportion of the heterotrophic bacterial population that was represented by UW85n 1 was generally largest right after planting and decreased at subsequent sampling times. Our results indicate that UW85nl grew and spread on soybean roots, and it persisted in the rhizosphere until seed harvest.
Article
A novel Gram-positive, rod-shaped, motile, spore-forming, nitrogen-fixing bacterium, designated strain 112(T), was isolated from cabbage rhizosphere in Beijing, China. The strain was found to grow at 10-40 °C and pH 4-11, with an optimum of 30 °C and pH 7.0, respectively. Phylogenetic analysis based on a fragment of the full-length 16S rRNA gene sequence revealed that strain 112(T) is a member of the genus Paenibacillus. High levels of 16S rRNA gene similarities were found between strain 112(T), Paenibacillus sabinae DSM 17841(T) (97.82 %) and Paenibacillus forsythiae DSM 17842(T) (97.22 %). However, the DNA-DNA hybridization values between strain 112(T) and the type strains of these two species were 10.36 and 6.28 %, respectively. The predominant menaquinone was found to be menaquinone 7 (MK-7). The major fatty acids were determined to be anteiso-C(15:0) and C(16:0). The major polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and unknown aminophospholipids. The cell wall peptidoglycan was found to contain meso-diaminopimelic acid. The DNA G+C content was determined to be 55.4 mol%. On the basis of its phenotypic characteristics, 16S rRNA gene sequence analysis and the value of DNA-DNA hybridization, strain 112(T) is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus brassicae sp. nov. is proposed. The type strain is 112(T) (= ACCC 01125(T) = DSM 24983(T)).