| 1. |
- Axelsson, J, et al.
(author)
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Decolorization of the textile dyes Reactive Red 2 and Reactive Blue 4 using Bjerkandera sp Strain BOL 13 in a continuous rotating biological contactor reactor
- 2006
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In: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229. ; 39:1, s. 32-37
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Journal article (peer-reviewed)abstract
- The decolorization of two different textile dyes, Reactive Red 2 and Reactive Blue 4, was studied in batch as well as continuous experiments using Bjerkandera sp. Strain BOL 13. The batch experiments were performed to study the decolorization of the dyes separately as well as in a mixture. The results from the experiments showed that the fungus decolorized both dyes. The absorbance was measured at 538 and 595 nm, the peak absorbance wavelengths of the red and blue dyes respectively. The absorbance decreased with 99% at both 538 and 595 nm in the experiments in which the dyes were studied separately at a concentration of 100 mg/l. The corresponding figure for the experiment in which the dyes were studied in a mixture was 98%. A continuous rotating biological contactor was then used to study the decolorization of mixtures of the two dyes at three different concentrations, e.g. 50, 100 and 200 mg/l of each of the dyestuff. The decrease in absorbance at 538 nm was 96% at the two lower dye concentrations while it was 81% at the highest concentration. The corresponding figures at 595 nm were 94 and 80%. The hydraulic retention time was 3 days. Scanning of the absorbance between 200 and 800 nm showed that three peaks disappeared in the UV range during treatment (246, 283 and 323.5 nm) and that a new plateau was formed around 270 nm. (c) 2005 Elsevier Inc. All rights reserved.
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| 2. |
- Lacayo, Martha, et al.
(author)
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Degradation of toxaphene by Bjerkandera sp. strain BOL13 using waste biomass as a cosubstrate
- 2006
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In: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 0175-7598 .- 1432-0614. ; 71:4, s. 549-554
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Journal article (peer-reviewed)abstract
- The white-rot fungus Bjerkandera sp. strain BOL13 was capable of degrading toxaphene when supplied with wood chips, wheat husk or cane molasses as cosubstrates in batch culture experiments. Approximately 85% of toxaphene was removed when wheat husk was the main substrate. The production of lignin peroxidase was only stimulated when wheat husk was present in the liquid medium. Although xylanase was always detected, wheat husk supported the highest xylanase production. A negligible amount of beta-glucosidase and cellulase were found in the batch culture medium. To the best of our knowledge, this is the first reported case of toxaphene degradation by white-rot fungi.
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| 3. |
- Munoz, Raul, et al.
(author)
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Sequential removal of heavy metals ions and organic pollutants using an algal-bacterial consortium
- 2006
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In: Chemosphere. - : Elsevier BV. - 1879-1298 .- 0045-6535. ; 63:6, s. 903-911
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Journal article (peer-reviewed)abstract
- The residual algal-bacterial biomass from photosynthetically supported, organic pollutant biodegradation processes, in enclosed photobioreactors, was tested for its ability to accumulate Cu(II), Ni(II), Cd(II), and Zn(II). Salicylate was chosen as a model contaminant. The algal-bacterial biomass combined the high adsorption capacity of microalgae with the low cost of the residual biomass, which makes it an attractive biosorbent for environmental applications. Cu(II) was preferentially taken-up from the medium when the metals were present both separately and in combination. There was no observed competition for adsorption sites, which suggested that Cu(II), Ni(II), Cd(II), and Zn(II) bind to different sites and that active Ni(II), Cd(II) and Zn(II) binding groups were present at very low concentrations. Therefore, special focus was given to Cu(II) biosorption. Cu(II) biosorption by the algal-bacterial biomass was characterized by an initial fast cell surface adsorption followed by a slower metabolically driven uptake. pH, Cu(II), and algal-bacterial concentration significantly affected the biosorption capacity for Cu(II). Maximum Cu(II) adsorption capacities of 8.5 +/- 0.4 mg g(-1) were achieved at an initial Cu(II) concentration of 20 mg l(-1) and at pH 5 for the tested algal-bacterial biomass. These are consistent with values reported for other microbial sorbents under similar conditions. The desorption of Cu(II) from saturated biomass was feasible by elution with a 0.0125 M HCl solution. Simultaneous Cu(II) and salicylate removal in a continuous stirred tank photobioreactor was not feasible due to the high toxicity of Cu(H) towards the microbial culture. The introduction of an adsorption column, packed with the algal-bacterial biomass, prior to the photobioreactor reduced Cu(II) concentration, thereby allowing the subsequent salicylate biodegradation in the photobioreactor.
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| 4. |
- Nordström, F, et al.
(author)
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Decolorization of a mixture of textile dyes using Bjerkandera sp. BOL-13.
- 2008
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In: Environmental Technology. - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 29:8, s. 921-929
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Journal article (peer-reviewed)abstract
- The white-rot fungus Bjerkandera sp. BOL-13 was evaluated regarding decolorization of four textile dyes Reactive blue 21, Reactive black 5, Reactive orange 13 and Reactive yellow 206. Experiments were performed in batch and continuous modes. The total dye concentration in all experiments was 100 mg l(-1). The results of the batch experiments showed that the fungus decolorized all dyes but at different rates. There was, however, an increase in the ultraviolet (UV) absorbance when a medium with a low concentration of nitrogen was used. No increase in UV range was observed when the nitrogen concentration was increased. A continuous experiment was performed to study the decolorization of a mixture of three of the dyes Reactive blue 21, Reactive black 5 and Reactive orange 13. Scanning of inlet and outlet samples showed that the absorbance at the peaks in the visible range decreased by 60-66%. The UV absorbance of the outlet increased during the first days of operation after which it decreased again to reach the same level as the inlet. The hydraulic retention time in the reactor was 3 days. The medium containing the higher nitrogen concentration was used in the continuous experiment.
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| 5. |
- Soares, Ana, et al.
(author)
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The ability of white-rot fungi to degrade the endocrine-disrupting compound nonylphenol
- 2005
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In: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 1432-0614 .- 0175-7598. ; 66:6, s. 719-725
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Journal article (peer-reviewed)abstract
- Phanerochaete chrysosporium, Pleurotus ostreatus, Trametes versicolor and Bjerkandera sp. BOL13 were tested for their ability to degrade the endocrine-disrupting compound nonylphenol at an initial concentration of 100 mg l–1. The highest removals were achieved with T. versicolor and Bjerkandera sp. BOL13, which were able to degrade 97 mg l–1 and 99 mg l–1 of nonylphenol in 25 days of incubation, respectively. Nonylphenol removal was associated with the production of laccase by T. versicolor, but the levels of laccase, manganese peroxidase and lignin peroxidase produced by Bjerkandera sp. BOL13 were very low. At 14°C, T. versicolor and Bjerkandera sp. BOL13 sustained the removal of 88 mg l–1 and 79 mg l–1 of nonylphenol, respectively. No pollutant removal was recorded at 4°C, although both fungi could grow at this temperature in the absence of nonylphenol. A microtoxicity assay showed that the fungi produced compounds that were toxic to Vibrio fischerii; and thus a reduction in toxicity could not be correlated with nonylphenol metabolism. T. versicolor and Bjerkandera sp. BOL13 were capable of colonizing soil artificially contaminated with 430 mg kg–1 of nonylphenol. Only 1.3±0.1% of nonylphenol remained in the soil after 5 weeks of incubation.
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| 6. |
- Terrazas, Enrique
(author)
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Fungal Redox Enzymes Involved in the Oxidation of Organic Pollutants
- 2005
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Doctoral thesis (other academic/artistic)abstract
- This work describes the degradation of nonylphenol, toxaphene, phenanthrene, benzo[a]pyrene and dyes using fungi and their redox enzymes. Two fungi, Bjerkandera sp. strain BOL13 and Fusarium sp. strain BOL35 were isolated from different geographic area in Bolivia. They were characterized genetically, physiologically and biochemically. Degradation of nonylphenol by Bjerkandera sp. strain BOL13 and T. versicolor was achieved in liquid cultures, as well as in polluted soil. Since laccase activity was detected in cultures of T. versicolor, an enzymatic mechanism appears be involved in its degradation. In contrast, in cultures of Bjerkandera sp strain BOL13 neither manganese peroxidase (MnP) nor lignin peroxidase (LiP) was detected, and a mechanism of free radicals may be involved. Phenanthrene degradation was achieved in a liquid medium by Bjerkandera sp. strain BOL13. MnP and LiP activity were detected in the cultures. Phenanthrene degradation was confirmed using extracellular fluid rich in enzyme activity. MnP can be active over a broad pH range, from 5 to 7. However, degradation at low pH in liquid media is preferable, since the optimal pH for lignin modifying enzyme activities are in the acidic range. Toxaphene, an organic chlorinated pesticide, was removed by Bjerkandera sp. strain BOL13. Waste biomass was used as co-substrate. The removal was related to LiP and xylanase activity. Wheat husk proved to be a better substrate for the production of LiP. Xylose the product of xylanase activity may be the source of H2O2. Several dyes, including Reactive red 2 and Reactive blue 4 were decolorized by Bjerkandera sp. strain BOL13. A continuous biological contactor was operated with a low-nitrogen and low-glucose content medium. This kind of reactor may be suitable for large-scale decolorization. The decolorization of dyes was better at acid pH. Operating the reactor at neutral pH, led to decrease in decolorization activity. As was expected, neither LiP nor MnP activity was detected at that pH. At neutral pH a coupling reaction was observed. This reaction was Mn2+ dependant, but interestingly was not required H2O2. Both phenanthrene and anthracene were degraded by combining MnP and the Fenton reagent. Degradation was attributed to the capability of the MnP to reduce Fe3+ and oxidize Fe2+. The reaction was carried in a liquid medium as well as in polluted soil at pH close to neutral. However, the Fenton reaction carried out at pH 3, showed better performance in removing PAHs. Degradation of organic pollutants at neutral pH or close are desirable, since native microorganisms can be affected at low pH, and the release of toxic heavy metals is favored in acidic pH. A mixture of two proteins with LiP and MnP activities was purified partially from Bjerkandera sp. strain BOL13. This mixture may be responsible for the degradation of recalcitrant compound with this strain. Fusarium sp strain BOL35 was characterized as a new species Fusarium santarosense. The fungus was able to degrade BaP. Laccase was present in its cultures. The production of a red pigment in the cultures was noticed. The absorption spectrum of the purified pigment was comparable to those obtained from naphthoquinone, common metabolites produced by Fusarium spp. Since degradation of BaP by F. santarosense can be attributed to a mechanism in which laccase and quinones, are involved. Laccase was characterized from Fusarium sp. strain BOL35. Dimethylated and tetramethylated aromatic compounds were found to be better substrates for the enzyme. The enzyme showed a different UV-Visible spectrum from those of blue laccase or yellow laccase, but its spectrum was comparable to those of white laccase, although with different substrate specificity.
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| 7. |
- Terrazas, Enrique, et al.
(author)
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Isolation and characterization of a white rot fungus Bjerkandera sp strain capable of oxidizing phenanthrene
- 2005
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In: Biotechnology Letters. - : Springer Science and Business Media LLC. - 1573-6776 .- 0141-5492. ; 27:12, s. 845-851
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Journal article (peer-reviewed)abstract
- Strain BOL13 was selected from 18 fungal strains isolated from an oil-spill contaminated site in Oruro, Bolivia. It was identified as a basidiomycete with high homology to Bjerkandera. The fungus degraded 100 mg phenanthrene l(-1) at 0.17 mg l(-1) d(-1) at 30 degrees C at pH 7. During phenanthrene degradation, a maximum manganese peroxidase activity of 100-120 U l(-1) was measured after 10 days of incubation. The ability of Bjerkandera sp. to produce lignin-modifying enzymes and to oxidize phenanthrene under various pH and temperature conditions was confirmed.
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