International Biodeterioration & Biodegradation

Published by Elsevier BV

Print ISSN: 0964-8305


Mycobacterium aromativorans JS19b1(T) Degrades Phenanthrene through C-1,2, C-3,4 and C-9,10 Dioxygenation Pathways
  • Article

May 2012


97 Reads



Mycobacterium aromativorans strain JS19b1(T) can utilize phenanthrene as a sole source of carbon and energy. Strain JS19b1(T) degrades phenanthrene through highly branched metabolic pathways, including dioxygenation on C-1,2, C-3,4 and C-9,10 positions and ring opening by both ortho- and meta-cleavage. The presence of novel metabolic pathways was confirmed by replacement cultivation using synthetic metabolite standards. The metabolites were isolated and identified by gas chromatography-mass spectrometry. Both ortho and meta-cleavage products of 1,2- and 3,4-dihydroxyphenanthrene were detected. Two ortho-cleavage products, 1-[(E)-2-carboxyvinyl]-2-naphthoic acid and 2-[(E)-2-carboxyvinyl]-1-napthoic acid were further metabolized to naphthalene-1,2-dicarboxylic acid and then to 1,2-dihydroxynaphthalene, which can also be produced from the meta-cleavage products hydroxynaphthoic acids. These results suggest that part of the branched pathways is merged into 1,2-dihydroxynaphthalene. The concentrations of the products from C-9,10 dioxygenation were higher than those from other pathways. C-9,10 dioxygenation of phenanthrene produced phthalic acid through decarboxylation and mono-/di-oxygenation. The diverse phenanthrene metabolic pathways in JS19b1(T) give a new insight of the bacterial degradation of polycyclic aromatic hydrocarbons.

Evaluation of dihydrooroidin as an antifouling additive in marine paint

June 2009


101 Reads

Christian Melander






Methods used to deter biofouling of underwater structures and marine vessels present a serious environmental issue and are both problematic and costly for government and commercial marine vessels worldwide. Current antifouling methods include compounds that are toxic to aquatic wildlife and marine ecosystems. Dihydrooroidin (DHO) was shown to completely inhibit Halomonas pacifica biofilms at 100 μM in a static biofilm inhibition assay giving precedence for the inhibition of other marine-biofilm-forming organisms. Herein we present DHO as an effective paint-based, non-cytotoxic, antifouling agent against marine biofouling processes in a marine mesocosm.

PVC biodeterioration and DEHP leaching by DEHP-degrading bacteria

April 2012


111 Reads

Newly isolated, not previously reported, di-(2-ethylhexyl) phthalate (DEHP)-degraders were augmented to assess their role in polyvinyl chloride (PVC) shower curtain deterioration and DEHP leaching. The biofilms that developed on the surfaces of the bioaugmented shower curtains with Gram-positive strains LHM1 and LHM2 were thicker than those of the biostimulated and Gram-negative strain LHM3-augmented shower curtains. The first derivative thermogravimetric (DTG) peaks of the bioaugmented shower curtains with the Gram-positive bacteria were observed at ~287°C, whereas the control and Gram-negative strain LHM3-augmented shower curtains were detected at ~283°C. This slight delay in the first DTG peak temperature is indicative of lower plasticizer concentrations in the shower curtains that were bioaugmented with Gram positive bacteria. Despite bioaugmentation with DEHP-degraders, aqueous solutions of the bioaugmentation reactors were not DEHP-free due probably to the presence of co-solutes that must have supported microbial growth. Generally, the bioaugmented reactors with the Gram-positive strains LHM1 and LHM2 had greater aqueous DEHP concentrations in the first-half (<3 wk) of the biodeterioration experiment than the biostimulated and strain LHM3-augmented reactors. Therefore, strains LHM1 and LHM2 may play an important role in DEHP leaching to the environment and PVC biodeterioration.

The role of microbial biofilms in deterioration of space station candidate materials

February 1998


162 Reads

Formation of microbial biofilms on surfaces of a wide range of materials being considered as candidates for use on the International Space Station was investigated. The materials included a fibre-reinforced polymeric composite, an adhesive sealant, a polyimide insulation foam, teflon cable insulation, titanium, and an aliphatic polyurethane coating. They were exposed to a natural mixed population of bacteria under controlled conditions of temperature and relative humidity (RH). Biofilms formed on the surfaces of the materials at a wide range of temperatures and RHs. The biofilm population was dominated by Pseudomonas aeruginosa, Ochrobactrum anthropi, Alcaligenes denitrificans, Xanthomonas maltophila, and Vibrio harveyi. The biocide, diiodomethyl-p-tolyl sulfone, impregnated in the polyurethane coating, was ineffective against microbial colonization and growth. Degradation of the polyurethane coatings was monitored with electrochemical impedance spectroscopy (EIS). The impedance spectra indicated that microbial degradation of the coating occurred in several stages. The initial decreases in impedance were due to the transport of water and solutes into the polymeric matrices. Further decreases were a result of polymer degradation by microorganisms. Our data showed that these candidate materials for space application are susceptible to biofilm formation and subsequent degradation. Our study suggests that candidate materials for use in space missions need to be carefully evaluated for their susceptibility to microbial biofilm formation and biodegradation.

Table 1 Chemical composition of the glass samples obtained from the Cathedral of Tarragona.
Fig. 3. Patina, leaching surface, and bio-pitting observed on glass samples. 3A: Macroscopic pictures corresponding to two Tarragona glass samples. Left image shows silica-leached surface directly in contact with glass and before patina (orange at bottom and more dark at top) developed in sample T-5. Right image shows detail of patina and bio-pitting
DGGE fingerprints of DNA fragments encoding the bacterial 16S rDNA, using a linear gradient of denaturants of 25–55% (A) and the fungal ITS1 region, using a linear gradient of denaturants of 20–40% (B) derived from sample T-5 of the Cathedral of Tarragona, as well as the profiles of sequenced clones. Nomenclature indicates the numbers of clones, as indicated in Tables 3and 4.
DGGE fingerprints of DNA fragments encoding bacterial 16S rDNA, using a linear gradient of denaturants of 25–60% (A) and the fungal ITS1 region, using a linear gradient of denaturants of 20–50% (B) derived from original stained glass window samples of the Cathedral of Tarragona and the church of Santa Maria del Mar. Numbers of lanes represent the different glass samples. T: Tarragona; STM: Santa Maria del Mar. M. marker: a mixture of Bacillus pumilus, Pseudomonas stutzeri, and Myxococcus xanthus (A), Cladosporium sp. (B).
Cathedral of Tarragona. 1A: Detail of the façade. 1B: Detail of the rosette glasses of the transept from the Cathedral of Tarragona. 1C: Detail of a glass piece with deterioration signs looking like Cladosporium attack.


Microscopic, chemical, and molecular-biological investigation of the decayed medieval stained window glasses of two Catalonian churches
  • Article
  • Full-text available

October 2013


950 Reads

We investigated the decayed historical church window glasses of two Catalonian churches, both under Mediterranean climate. Glass surfaces were studied by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). Their chemical composition was determined by wavelength-dispersive spectrometry (WDS) microprobe analysis. The biodiversity was investigated by molecular methods: DNA extraction from glass, amplification by PCR targeting the16S rRNA and ITS regions, and fingerprint analyses by denaturing gradient gel electrophoresis (DGGE). Clone libraries containing either PCR fragments of the bacterial 16S rDNA or the fungal ITS regions were screened by DGGE. Clone inserts were sequenced and compared with the EMBL database. Similarity values ranged from 89 to 100% to known bacteria and fungi. Biological activity in both sites was evidenced in the form of orange patinas, bio-pitting, and mineral precipitation. Analyses revealed complex bacterial communities consisting of members of the phyla Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Fungi showed less diversity than bacteria, and species of the genera Cladosporium and Phoma were dominant. The detected Actinobacteria and fungi may be responsible for the observed bio-pitting phenomenon. Moreover, some of the detected bacteria are known for their mineral precipitation capabilities. Sequence results also showed similarities with bacteria commonly found on deteriorated stone monuments, supporting the idea that medieval stained glass biodeterioration in the Mediterranean area shows a pattern comparable to that on stone.

Fig. 1. Degradation kinetics of phenanthrene (A) by and growth curve (B) of S. maltophilia strain C6. Error bars represent the standard deviations of triplicate samples. Phe, phenanthrene.
Fig. 2.
Fig. 4.
Multiple degradation pathways of phenanthrene by Stenotrophomonas maltophilia C6

April 2013


115 Reads

Stenotrophomonas maltophilia strain C6, capable of utilizing phenanthrene as a sole source of carbon and energy, was isolated from creosote-contaminated sites at Hilo, Hawaii. Twenty-two metabolites of phenanthrene, covering from dihydrodiol to protocatechuic acid, were isolated and characterized. Phenanthrene was degraded via an initial dioxygenation on 1,2-, 3,4-, and 9,10-C, where the 3,4-dioxygenation and subsequent metabolisms were most dominant. The metabolic pathways were further branched by ortho- and meta-cleavage of phenanthrenediols to produce 1-hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, and naphthalene-1,2-dicarboxylic acid. These intermediates were then transformed to naphthalene-1,2-diol. 1-Hydroxy-2-naphthoic acid was also degraded via a direct ring cleavage. Naphthalene-1,2-diol underwent primarily ortho-cleavage to produce trans-2-carboxycinnamic acid and then to form phthalic acid, 4,5-dihydroxyphthalic acid and protocatechuic acid. Accumulation of salicylic acid in prolonged incubation indicated that a limited extent of meta-cleavage of naphthalene-1, 2-diol also occurred. This is the first study of detailed phenanthrene metabolic pathways by Stenotrophomonas maltophilia.

DGGE profiles generated from 18S cDNA of untreated control (a), freeze-dried (b), and gamma ray- (c) treated paper samples one year after the application of treatments (T2). Lanes contain marker (M), mixed inocula (Mix) on paper types A and D (lanes 1 and 2), Chaetomium globosum (Ch) on paper types A and D (lanes 3 and 4), Trichoderma viride (Tr) on paper types A and D (lanes 5 and 6), and Cladosporium cladosporioides (Cl) on paper types A (lane 7). Marked bands indicate the position of each fungus on DGGE: C. Cladosporioides (B1, in A and B4 in 3C), Ch. globosum (B2), and T. viride (B3).
DGGE profiles generated from ITS1 derived DNA of untreated control (a), freeze-dried (b), and gamma ray- (c) treated paper samples extracted after one month of the application of treatments (T1) and one year later (T2). Lanes contain marker (M), mixed inocula (Mix) on paper types A and D (lanes 1 and 2), Chaetomium globosum (Ch) on paper types A and D (lanes 3 and 4), Trichoderma viride (Tr) on paper types A and D (lanes 5 and 6), and Cladosporium cladosporioides (Cl) on paper type A (lanes 7). No DNA was obtained for any sample treated with EtO. The marker contains, among others, fragments from C. cladosporioides (b1), Ch. globosum (b2), and T. viride (b3).
Example of a 25-point inoculum of Chaetomium globosum on paper A taken from control paper samples. The development of mycelium in the points allows for a statistical comparison between different treatments and untreated control samples. In the control sample all the 25 fragments of paper produced a colony after the inoculation on nutritive agar.
Monitoring the effects of different conservation treatments on paper-infecting fungi

October 2013


523 Reads

Fungi are among the most degradative organisms inducing biodeterioration of paper-based items of cultural heritage. Appropriate conservation measures and restoration treatments to deal with fungal infections include mechanical, chemical, and biological methods, which entail effects on the paper itself and health hazards for humans. Three different conservation treatments, namely freeze-drying, gamma rays, and ethylene oxide fumigation, were compared and monitored to assess their short- (one month, T1) and long-term (one year, T2) effectiveness to inhibit fungal growth. After the inoculation with fungi possessing cellulose hydrolysis ability — Chaetomium globosum, Trichoderma viride, and Cladosporium cladosporioides — as single strains or as a mixture, different quality paper samples were treated and screened for fungal viability by culture-dependent and -independent techniques. Results derived from both strategies were contradictory. Both gamma irradiation and EtO fumigation showed full efficacy as disinfecting agents when evaluated with cultivation techniques. However, when using molecular analyses, the application of gamma rays showed a short-term reduction in DNA recovery and DNA fragmentation; the latter phenomenon was also observed in a minor degree in samples treated with freeze-drying. When RNA was used as an indicator of long-term fungal viability, differences in the RNA recovery from samples treated with freeze-drying or gamma rays could be observed in samples inoculated with the mixed culture. Only the treatment with ethylene oxide proved negative for both DNA and RNA recovery. Therefore, DNA fragmentation after an ethylene oxide treatment can hamper future paleogenetic and archaeological molecular studies on the objects.

Laccase mediated decolorization of vat dyes by Coriolus versicolor IBL-04

December 2008


180 Reads

Five indigenous white rot fungi Pleurotus ostreatus IBL-02, Phanerochaete chrysosporium IBL-03, Coriolus versicolor IBL-04, Ganoderma lucidum IBL-05 and Schizophyllum commune IBL-06 were screened for decolorization of four vat dyes, Cibanon red 2B-MD, Cibanon golden-yellow PK-MD, Cibanon blue GFJ-MD and Indanthrene direct black RBS. The screening experiment was run for 10 days with 0.01% dye solutions prepared in alkaline Kirk's basal nutrient medium in triplicate (250 ml flasks). Every 48 h samples were read on their respective wavelengths (λmax) to determine the percent decolorization. It was observed that C. versicolor IBL-04 could effectively decolorized all the four vat dyes at varying incubation times but best results were shown on Cibanon blue GFJ-MD (90.7%) after 7 days, followed by golden-yellow (88%), Indanthrene direct black (79.7%) and Cibanon red (74%). P. chrysosporium also showed good decolorization potential on Cibanon blue (87%), followed by Cibanon golden-yellow (74.8%), Red (71%), and Indanthrene direct black (54.6%). However, rest of the strains showed poor decolorization potential on four vat dyes. C. versicolor showing maximum decolorization of Cibanon blue GFJ-MD was, therefore, selected for process optimization. The effect of varying pH, temperature, initial dye concentration and addition of carbon and nitrogen sources was investigated. Maximum decolorization (98.5%) of 0.01% Cibanon blue GFJ-MD could be achieved after 3 days at pH 5 and 30 °C temperature in the nutrient medium supplemented with 1% starch as additional carbon source. All the supplementary nitrogen sources were found inhibitory to laccase activity and dye decolorization. It was also noted that there was negligible adsorption of the dye on fungal mycelia and laccase catalyzed biodegradation was the major decolorization route.

Catalytic activity of Pseudomonas putida strain G7 naphthalene 1,2-dioxygenase on biphenyl

July 1999


25 Reads

Naphthalene dioxygenase (NAP dox) catalyzes the first reaction of the naphthalene catabolic pathway encoded by the NAH plasmid. Similar to other aryl hydroxylating dioxygenases, NAP dox introduces molecular oxygen on two vicinal carbons of the aromatic ring. In this work it is shown that Pseudomonas putida G7 NAP dox (NAP doxG7) can catalyze the oxygenation of biphenyl quite efficiently. Similar to biphenyl dioxygenase which is the homologous reaction of the biphenyl catabolic pathway, the enzyme attack biphenyl molecule onto the ortho-meta carbons preferentially. However, unlike biphenyl dioxygenase of Pseudomonas sp. LB400, NAP doxG7 dioxygenates a non negligible portion of the substrate onto the meta-para carbons.

Biodegradation of 1,2-dichloroethane (1,2-DCA) by cometabolism in a nitrifying biofilm reactor

July 2010


167 Reads

Biodegradation of 1,2-dichloroethane (1,2-DCA) by cometabolism was investigated in a continuous-flow nitrifying biofilm reactor over a time period of 218 days. The removal efficiency of 1,2-DCA ranged between 70 and 90%. Using the generation of chloride (Cl−) as an indicator of 1,2-DCA mineralization, it was shown that the cometabolic degradation of 1,2-DCA was initiated through oxidative dechlorination. However, Cl− production rates were observed to be lower than the stoichiometric ones which indicated the partial mineralization of 1,2-DCA and the possibility of by-product formation due to incomplete dechlorination. At high 1,2-DCA removal rates, Cl− release seemed to reach a saturation due to 1,2-DCA-dependent inactivation of NH4–N oxidation. The cometabolic 1,2-DCA degradation capacity of nitrifiers was quite comparable to metabolic 1,2-DCA degradation capacities of pure cultures. A strong linear relationship was found between 1,2-DCA transformation yields and NH4–N and 1,2-DCA loadings. The effect of 1,2-DCA loading on nitrifier population was monitored using molecular microbiological tools. Long-term input of 1,2-DCA to the biofilm reactor resulted in no significant changes in the quantities of Nitrosomonas, Nitrobacter and Nitrospira species and no shift in the diversities of ammonia oxidizing species. Those findings provide an insight into both the operation and the community structure in natural and managed nitrifying biofilm systems where cometabolic 1,2-DCA takes place.

The effect of 1,2-benzanthracene and 3, 4-benzpyrene on the ultrastructure of maize cells

March 1998


25 Reads

The action of different concentrations of 1,2-benzanthracene and 3,4-benzpyrene on maize root cell ultrastructural organization was studied. It has been shown that low concentrations of xenobiotics (1,2-benzanthracene 20–100 μg/ml; 3,4-benzpyrene 2.6 × 10−9–2.6 × 10−8 μg/ml) do not cause noticeable changes on ultrastructural level due to the cell's ability to assimilate and metabolize them. At the same time, these low concentrations of 3,4-benzpyrene inhibit DNA synthesis in nuclei. Higher concentrations of 1,2-benzanthracene (200 μg/ml) and 3,4-benzpyrene (2.6 × 10−7–2.6 × 10−5 μg/ml) lead to significant ultrastructural changes up to the complete destruction of the cell.

Induction and catalytic properties of an intracellular NADH-dependent 1,4-benzoquinone reductase from the brown-rot basidiomycete Gloeophyllum trabeum

July 2004


33 Reads

The expression of intracellular NADH-dependent 1,4-benzoquinone reductase in the brown-rot fungus Gloeophyllum trabeum was increased in the presence of 2,6-dimethoxy-1,4-benzoquinone (2,6-DMBQ) and, to a lesser extent, vanillic acid. Expression was time-dependent and influenced by nitrogen levels. An intracellular NADH-dependent 1,4-benzoquinone reductase was purified from G. trabeum. The subunit molecular mass was . Flavin mononucleotide was the coenzyme. The pI of the enzyme was 4.2. The quinone reductase catalyzed the reduction of multiple 1,4-quinones and exhibited Ping–Pong kinetics. For enzyme-catalyzed 2,6-DMBQ reduction, the apparent KM was and the ; the pH optimum was between 5.5 and 7; the activation energy of the reaction was estimated at . The one-to-one stoichiometric ratio of NADH oxidation versus 2,6-DMBQ reduction suggested a two-electron transfer mechanism for the enzyme. Dicumarol and Cibacron blue were competitive inhibitors with Ki values of 0.5 and , respectively.

Synergistic wood preservatives involving EDTA, irganox 1076 and 2-hydroxypyridine-N-oxide

April 2005


218 Reads

The efficiency of 2-hydroxypyridine-N-oxide (2-HPNO) against wood degradation by the white-rot fungus Coriolus versicolor was demonstrated by monitoring weight loss of treated and untreated wood blocks. The fungistatic properties of 2-HPNO are related to the presence of the hydroxamic acid function as shown using several analogs. Using response surface methodology, strongly significant synergy was observed between either the chelator ethylenediaminetetraacetic acid (EDTA) and 2-HPNO or the hindered phenolic antioxidant Irganox 1076 and 2-HPNO. 2-HPNO is subjected to oxidation by peroxidase explaining the synergy observed with the antioxidant. The chelating properties of 2-HPNO may also explain the synergy observed with EDTA. The implications of the observed synergy for the design of new wood preservation strategies are also discussed.

Biodegradation of textile azo dyes by a facultative Staphylococcus arlettae strain VN-11 using a sequential microaerophilic/aerobic process

April 2009


640 Reads

A facultative Staphylococcus arlettae bacterium, isolated from an activated sludge process in a textile industry, was able to successfully decolourize four different azo dyes under microaerophilic conditions (decolourization percentage >97%). Further aeration of the decolourized effluent was performed to promote oxidation of the degradation products. The degradation products were characterized by FT-IR and UV–vis techniques and their toxicity with respect to Daphnia magna was measured. The amine concentrations as well as the total organic carbon (TOC) levels were monitored during the biodegradation process. The presence of aromatic amine in the microaerophilic stage and its absence in the aerobic stage indicated the presence of azoreductase activity and an oxidative biodegradation process, respectively. TOC reduction was ∼15% in the microaerophilic stage and ∼70% in the aerobic stage. The results provided evidence that, using a single Staphylococcus arlettae strain in the same bioreactor, the sequential microaerophilic/aerobic stages were able to form aromatic amines by reductive break-down of the azo bond and to oxidize them into non-toxic metabolites.

Extensive biodegradation of highly chlorinated biphenyl and Aroclor 1242 by Pseudomonas aeruginosa TMU56 isolated from contaminated soils

September 2009


107 Reads

A bacterial strain, designated TMU56, was isolated from soil that had been contaminated with electrical transformer fluid (Askarel) for over 35 years. The isolate was identified as Pseudomonas aeruginosa using its 16S rDNA sequence. This strain was found to grow on monochlorobiphenyls (CBs), including 2-chlorobenzoic acid and 4-chlorobenzoic acid. It was also found to grow on 2,4-, 2,5-, 2,2′-, and 4,4′-diCB, as well as on a wide range of other xenobiotic compounds. This is the first reported representative of the genus Pseudomonas that is capable of growing on 2,4,4′-triCB, 2,2′,5,5′-tetraCB and 2,2′,4,4′,5,5′-hexaCB as sole carbon sources. Washed benzoate-grown cells were able to degrade 89% and 56% of 2,4-diCB and 2,2′,4,4′,5,5′-hexaCB, respectively. Gas chromatography analysis of individual congeners in Aroclor 1242 (200 ppm) following a 4-day incubation showed 73.3% degradation of PCBs without the need for biphenyl as an inducer. The strain exhibited no noticeable specificity for the percentage of congener transformation or degree of chlorination.

Characteristics of an Endophytic Pyrene-Degrading Bacterium of Enterobacter sp. 12J1 from Allium macrostemon Bunge

September 2008


128 Reads

One pyrene-degrading endophytic bacterium was isolated from plants grown in polycyclic aromatic hydrocarbon-contaminated soils and identified as Enterobacter sp. 12J1 based on the 16S rDNA gene sequence analysis. Heavy metal and antibiotic resistance, degradation of pyrene, solubilization of inorganic phosphate and cell surface hydrophobicity characteristics of the isolate were further characterized. The isolate was also evaluated for promoting plant growth of wheat and maize and pyrene removal from pyrene-amended soil in pot experiments. High-performance liquid chromatograph (HPLC) analysis showed that the degradation rate of pyrene (5 mg l−1) by the endophytic bacterial strain 12J1 was 83.8% under 28 °C for 7 days. The Enterobacter sp. 12J1 could produce indole acetic acid (IAA), siderophore and solubilize inorganic phosphate. The Enterobacter sp. 12J1 also has a cell surface hydrophobicity. In the live bacterial inoculation experiment, an increase in pyrene removal varying from 60% to 107% was observed in the planted soils treated with 100 mg kg−1 of pyrene compared with the unplanted soils. The rate of pyrene removal increased by 43–65% in the live bacterium-inoculated planted soils compared with the dead bacterium-inoculated planted soils. Although there were no significant differences in the total culturable bacterial numbers between live and dead bacterial inoculation, the numbers of pyrene-degrading bacteria were significantly greater in the live bacterium-inoculated planted or unplanted soils. The isolate could colonize the tissue (root and stem) interiors and rhizosphere soils of wheat and maize after root inoculation.

Biodegradation of Methyl red by Galactomyces geotrichum MTCC 1360

September 2008


213 Reads

Galactomyces geotrichum MTCC 1360 can decolorize triphenylmethane, azo and reactive high exhaust textile dyes. At shaking condition this strain showed 100% decolorization of a toxic azo dye Methyl red (100 m gl−1) within 1 h in deionized water at 30 °C. The degradation of Methyl red was possible through a broad pH (3–12) and temperature (5–50 °C) range. Glucose and mycelium concentration had increased the decolorization rate, but the addition of 1 gl−1 molasses in deionized water made decolorization possible in only 10 min. Induction in the NADH–dichloro phenol indophenol (NADH–DCIP) reductase, Malachite green reductase, laccase and lignin peroxidase (Lip) activities were observed in the cells obtained after complete decolorization, showing that there is direct involvement in the degradation of Methyl red. The absence of N-N′-dimethyl-p-phenylenediamine (DMPD) in 5 °C, 2-aminobenzoic acid (ABA) in 50 °C and both the compounds in 30 °C sample have shown the differences in the metabolic fate of Methyl red at different temperatures. The untreated dye at 300 mg l−1 concentration showed 88% germination inhibition in Sorghum bicolor, whereas it was 72% in Triticum aestivum. There was no germination inhibition for both the plants by Methyl red metabolites at 300 mg l−1 concentration.

Use of 13C NMR, sorption and chemical analyses for characteristics of brown-rotted Scots pine

January 2001


36 Reads

To define the decomposition patterns of wood cell wall, three economically important brown-rot fungi, Coniophora puteana, Postia placenta, and Gloeophyllum trabeum were studied. Degraded Scots pine (Pinus sylvestris L.) sapwood blocks were analysed using 13C NMR spectroscopy, chemical, and water vapor sorption methods. C. puteana caused the most wood decay (55%) after 50 days of exposure, while the destructive abilities of P. placenta and G. trabeum were 32 and 30%, respectively. Hemicellulose was removed preferably to cellulose, but the intensity of depletion depended on the fungus species rather than the mass loss. P. placenta and C. puteana removed 11.8 and 14.7% of the lignin, respectively, while G. trabeum removed 25.2%. The possible re-polymerization of lignin stopped any further lignin degradation during attack by C. puteana and P. placenta, while G. trabeum continued to degrade lignin until the end of the test. Removal of lignin metoxyl groups and formation of the reactive phenolic hydroxyl groups can be coupled to the reactions of Fenton reagents or other powerful oxidants in acidic conditions. Removal of hemicellulose and lignin (primarily methoxyl groups) will promote further access of fungal metabolites to cellulose fibers. A common regularity of the surface A accessible to water molecules and the losses of the wood weight was obtained. The mass hydrophilicity of sorbent am in brown-rotted wood tended to decrease as the share of lignin increased.

Decay of cultivated apricot wood (Prunus armeniaca) by the ascomycete Hypocrea sulphurea, using solid state 13C NMR and off-line TMAH thermochemolysis with GC–MS

April 2005


136 Reads

Chemical changes of polysaccharides and lignin in Prunus armeniaca decayed by the ascomycete fungus Hypocrea sulphurea were investigated. Solid-state 13C NMR spectra showed that polysaccharides were the main components of fresh and decayed wood. Decomposition of cellulose and hemicellulose by the fungus was minimal although a slight preference for crystalline as compared with amorphous cellulose was recognised. Comparison of the signal intensity of the resonance at 145 ppm in fresh and decomposed wood suggested that the fungus had decomposed tannin constituents. Thermochemolysis with tetramethylammonium hydroxide (TMAH) and product identification by gas chromatography–mass spectrometry revealed that the ratio of syringyl-type (S) units to guaiacyl-type (G) units decreased from 1.8 to 1.1 following fungal attack. Increases in both guaiacyl and syringyl acid-aldehyde ratios (Ad/Al)G, (Ad/Al)S together with an increase from 0.82 to 3.54 in the ratio of methyl 3,4-dimethoxybenzoate to the sum of 1-(3,4-dimethoxyphenyl)-1,2,3-trimethoxypropane (threo and erythro-isomers) ΓG from the decayed wood confirmed oxidative Cα–Cβ cleavage for the mechanism of lignin decay by this ascomycete.

Isolation of bacteria and fungi from TNT-contaminated Compost and Preparation of 14C-ring Labeled TNT

December 1995


22 Reads

TNT and its transformation products constitute a special contamination problem for the military. In addition to their explosive properties, these compounds are toxic to animals, plants and microorganisms and thus have detrimental effects on both human health and natural ecosystems. Composting is under consideration as a biological method for treating munitions-contaminated soils. In order better to characterize the microbial consortia associated with composting, we have isolated both bacteria and fungi from TNT-contaminated soils and composts. Fungi were identified as members of the genera Alternaria, Aspergillus, Penicillium and Trichoderma. Isolates varied in their TNT tolerance on complex liquid and solid media. Finally, a simple method for preparing 14C-TNT is presented.

Table 1 Effect of nutrients amendments and sterilization on MCPP mineralization and CO 2 production 
Table 2 Effect of nutrients amendments and sterilization on MCPP biodegradation and/or uptake by bacterial mass 
residues in the culturing media as a result of nutrients amendments and sterilization 
Effect of nutrient amendments and sterilization on mineralization and/or biodegradation of 14C-labeled MCPP by soil bacteria under aerobic conditions

April 2007


129 Reads

Mineralization and/or degradation of the phenoxy herbicide mecoprop (MCPP) by a group of soil bacteria under the effects of nutrient amendments and sterilization were investigated. Five different species of Pseudomonas (P. paucimobilis, P. aeruginosa, P. mallei, P. pseudomallei, and P. pickettii) were isolated from sediments of Lake Mariut, a freshwater lake in south Alexandria, Egypt. MCPP mineralization and/or removal were tested by the selected Pseudomonas species as active and dead masses in minimal and nutrient-rich media supplemented with 14C-MCPP at a final concentration of 10 μg l−1 for 6 successive weeks. Results revealed significant variations in the removal percentages of MCPP by either mineralization or biodegradation. Pseudomonas spp. exhibited high selectivity toward MCPP. Considering the short duration of the experiment (45 days) Pseudomonas spp. investigated in this study provide an effective and selective potential for MCPP decontamination. As a general trend, all of the investigated species exhibited higher biodegradation and removal efficiency of MCPP (1.3–89.5%) compared to their mineralization abilities (0.10–9.28%) under the experimental conditions. Also the highest MCPP mineralization and degradation by the selected Pseudomonas spp. were achieved by their inactive (dead) followed by active-rich cultures (both were inoculated in nutrient-rich medium), confirming the positive effects of nutrient amendments and sterilization on MCPP decontamination. Efficiency of Pseudomonas spp. was positively correlated with time up to the 3rd week for biodegradation and up to the 6th week for mineralization, indicating high mineralization efficiency provided enough time. Finally, Pseudomonas spp. showed selective preferences among them toward MCPP with the highest mineralization efficiency achieved by P. aeruginosa (1SB) and P. mallei (2SA), while the highest biodegradation efficiency was achieved by P. pickettii (5SB) and P. pseudomallei (3S). They seemed very promising but require longer exposure and higher MCPP concentration to stimulate and enhance their metabolic and mineralization capabilities. Results of this study can be manipulated efficiently to select the most promising Pseudomonas species for decontaminating polluted systems providing the optimum degradation conditions.

Assessment of blue-stain resistance according to the EN 152 and a reverse test method using visual and computer-aided techniques

June 2006


151 Reads

A computer technique for assessing blue-stained coated wood has been implemented for evaluating the discoloration of coatings and analysing the interior wood staining of samples subjected to testing according to European Standard EN 152. The comparison of visual assessment and computer-evaluated percentages of blue staining is based on a combination of correlation measures, principal components and cluster analysis. It appears difficult to imitate human evaluation with image processing, since computer ratings represent exact percentages, while subjective evaluations do not. Additionally, more specific techniques for exploring fungal growth in coated wood have been described. As EN 152 was specifically developed for testing efficacy of wood preservatives, a modified test methodology was elaborated for testing the efficacy of wood coatings, called here as the EN 152-reverse method. Furthermore three-dimensional (3D) reconstruction is validated as a tool for in-depth analysis of blue-stain disfigurement. This 3D visualisation indicates important differences in fungal infestation and proves its suitability for blue-stain resistance testing.

Treatment of a simulated textile wastewater containing the azo-dye reactive orange 16 in an anaerobic-biofilm anoxic–aerobic membrane bioreactor

October 2010


99 Reads

This study evaluated the treatability of simulated textile wastewaters in a bench-scale experimental system, comprising an anaerobic biofilter, an anoxic reactor and an aerobic membrane bioreactor. The Reactive Orange 16 (RO16) was used as model of azo dye. The proposed system was demonstrated to be effective in the treatment of the synthetic wastewater under the operating conditions applied in the study. The results demonstrate that neither the azo dye, nor the aromatic amines formed by the anaerobic azo-bond cleavage seem to significantly affect the COD and nitrogen removal under the operating conditions applied. Although aromatic amines are considered easily degradable under aerobic conditions, the results confirms that at least the sulfonated aromatic amines formed under anaerobic conditions from the RO16 are recalcitrant to biodegradation and therefore aromatic amines are still a matter of concern for the biological treatment of textile wastewater.

Use of anaerobic soil slurry reactors for the removal of petroleum hydrocarbons in soil. International Biodeterioration & Biodegradation, 52, 161-166

October 2003


63 Reads

The biodegradation of No. 2 diesel fuel under anaerobic conditions was investigated using anaerobic soil slurry reactors. Soil samples were collected from a diesel spill site, where the diesel spill has migrated to vadose zone. The purpose of this study was to find out which of the various groups of anaerobic bacteria present in the study site will degrade the petroleum hydrocarbons in the soil. The various anaerobic groups included sulfate-, nitrate-reducing, methanogenic, and mixed electron acceptor conditions. The results indicated enhanced biodegradation of diesel fuel under all conditions compared to no electron-supplemented reactor (passive bioremediation). However, the rate of diesel degradation was the highest under mixed electron acceptor conditions followed in order by sulfate-, nitrate-reducing, and methanogenic conditions. Under mixed electron acceptor condition, 80.5% removal of diesel fuel was achieved within 290 days. While under sulfate-reducing condition 55% degradation of diesel fuel was observed for the same period. This study showed that the mixed heterogeneous microbial population of the contaminated site has the metabolic capability to degrade diesel fuel.

Biodeterioration and restoration of a 16th-century book using a combination of conventional and molecular techniques: A case study

March 2009


429 Reads

In this paper we deliver a report on the study of microbiological damage found on the pages of a 16th-century book. Our aim is to describe the procedures needed to ensure a conservative approach to the restoration of valuable books and objects of art made from, or supported on, paper. The techniques employed to evaluate and describe the damage observed, as well as the organisms responsible for biodeterioration, are discussed. A range of sampling techniques and instruments were utilised, including swabs and adhesive tape. Conventional methods, such as classic culturing and the direct microscopic observation of sampled material, were coupled with DNA-fingerprinting and phylogenetic analysis. We postulated that the purple stains which migrate through the pages with a felted consistency (Fig. 2), based on all the information obtained using traditional and molecular means, were caused by a cellulolytic fungus producing purple essudates, characterised by echinated conidia and Hülle cells. These elements were consistent with the discovery of both A. versicolor and A. nidulans using molecular techniques.

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