• Journal of the Korean Wood Science and Technology
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• 제27권4호
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• pp.1-14
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• 1999

As the biodegradation of wood constituents has been understood as a multi-basidiomycetes and enzymatic processes, this review will focus on the roles of low molecular compounds and radicals working in harmony with fungal enzymes. Wood rotting basidiomycete fungi penetrate wood, and lead to more easily metabolize carbohydrates of the wood complex. The white-rot fungi, having versatile enzymes, are able to attack directly the "lignin barrier". They also use a multi-enzyme system including so-called "feedback" type enzymes allowing for simultaneous degradation of lignin and carbohydrates. The multi-enzymes including laccase support the proposed route by explaining how the high molecular weight enzymes can function in the wood complex. These enzymes may function separately or cooperate each other. In addition, veratryl alcohol oxidase, cellobiose dehydrogenase, arylalcohol dehydrogenase, and particularly low molecular mediators and radicals have an important role in wood biodegradation. However, the possibility of other mechanism as well as other enzymes, as operating as feedback systems in the process of wood degradation, could not be excluded.

• Journal of the Korean Wood Science and Technology
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• 제26권3호
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• pp.63-72
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• 1998

In order to evaluate the biodegradability and mechanism of 4,5,6-trichloroguaiacol (TCG) produced from bleaching process in pulp mill by Phanerochaete chrysosporium, Trametes versicolor, and Inonotus cuticularis, changes in TCG and its metabolites during biodegradation were analyzed by HPLC, and GC/MS spectrometry. By three fungi, the maximum biodegradability against TCG were very quickly reached, compared with other chlorinated aromatic compounds such as PCP. Within 24 hrs, T versicolor indicated up to 95% of TCG removal rate, and P. chrysosporium and I. cuticularis also showed more than 80%, and 90%, respectively. Particularly, in case of T. versicolor, the removal rate of TCG after 1 hr. incubation was reached to approximately 90%, implying very rapid metabolization of TCG. However, by analyzing the filtrates extracted from TCG containing culture by GC/MS, the major metabolites at initial stage of biodegradation were dimers, indicating that the added TCG monomers were quickly polymerized. The others were trichloroveratrole, dichloroguaiacol, and trichlorobenzoic acid, suggesting that TCG may be biodegraded by several sequential reactions such as polymerization, oxidation, methylation, dechlorination, and hydroxylation. In other experiments, the extracellular fluid which did not contain any fungal mycelia was used to evaluate the effect of mycelia on TCG biodegradation. The extracellular fluid of T. versicolor also biodegraded TCG up to 90% within 24hrs, but those of P. chrysosporium and I. cuticularis did not show any good biodegradability. T versicolor showed the highest value of laccase, and other two fungi indicated a little activity of lignin peroxidase (LiP) and manganese peroxidase (MnP). In addition, the laccase activity of T. versicolor was very linearly proportional to the removal rate of TCG during incubation, in other words, showing the induction effect against TCG. Consequently, the biodegradation of TCG was very dependent upon the activity of laccase.

• Mycobiology
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• 제48권5호
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• pp.383-391
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• 2020

Use of nanoparticles (NPs) in several commercial products has led to emergence of novel contaminants of air, soil and water bodies. The NPs may exhibit greater ecotoxicity due to nano-scale dependent properties over their bulk counterparts. The present investigation explores the effect of in vitro supplementation of TiO₂, silica and silver NPs on radial growth and ultrastructural changes in the hyphae and spores of two mushroom genera, Ganoderma lucidum and Volvariella volvaceae. A concentration dependent decrease in radial growth on NP amended potato dextrose agar medium was recorded. However, in comparison to control, there was decrease in radial diameter on supplementation with TiO₂ NPs while an increase was recorded for silica and silver NPs amendments as compared to their bulk salts at same concentrations after 48 h of incubation. Optical microscopy studies showed decrease in the number of spores while increase in spore diameter and thinning of hyphal diameter on NPs supplementation. Scanning electron microscopy analysis of fungal growth showed presence of deflated and oblong spores in two fruiting strains of Ganoderma while Volvariella exhibited decreased sporulation. Further, hyphal thinning and branching was recorded in response to NP amendments in both the test mushrooms. Enhancement of protein content was observed on NP compared to bulk supplementation for all cultures, concentrations and hours of incubation except for TiO₂ NPs. Likewise, bulk and NP supplementations (at 100 mg L^-1) resulted in enhanced laccase activity with occurrence of laccase specific protein bands on SDS-PAGE analysis.

• Mycobiology
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• 제37권1호
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• pp.53-61
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• 2009

The process of biodegradation in lingo-cellulosic materials is critically relevant to biospheric carbon. The study of this natural process has largely involved laboratory investigations, focused primarily on the biodegradation and recycling of agricultural by-products, generally using basidiomycetes species. In order to collect super white rot fungi and evaluate its ability to degrade lingo-cellulosic material, 35 fungal strains, collected from forests, humus soil, livestock manure, and dead trees, were screened for enzyme activities and their potential to decolorize the commercially used Poly-R 478 dye. In the laccase enzymatic analysis chemical test, 33 white rot fungi and 2 brown rot fungi were identified. The degradation ability of polycyclic aromatic hydrocarbons (PAHs) according to the utilized environmental conditions was higher in the mushrooms grown in dead trees and fallen leaves than in the mushrooms grown in humus soil and livestock manure. Using Poly-R 478 dye to assess the PAH-degradation activity of the identified strains, four strains, including Agrocybe pediades, were selected. The activities of laccase, MnP, and Lip of the four strains with PAH-degrading ability were highest in Pleurotus incarnates. 87 fungal strains, collected from forests, humus soil, livestock manure, and dead trees, were screened for enzyme activities and their potential to decolorize the commercially used Poly-R 478 dye on solid media. Using Poly-R 478 dye to assess the PAHdegrading activity of the identified strains, it was determined that MKACC 51632 and 52492 strains evidenced superior activity in static and shaken liquid cultures. Subsequent screening on plates containing the polymeric dye poly R-478, the decolorization of which is correlated with lignin degradation, resulted in the selection of a strain of Coriolus versicolor, MKACC52492, for further study, primarily due to its rapid growth rate and profound ability to decolorize poly R-478 on solid media. Considering our findings using Poly-R 478 dye to evaluate the PAH-degrading activity of the identified strains, Coriolus versicolor, MKACC 52492 was selected as a favorable strain. Coriolus versicolor, which was collected from Mt. Yeogi in Suwon, was studied for the production of the lignin-modifying enzymes laccase, manganese-dependent peroxidase (MnP), and lignin peroxidase (LiP).

• Journal of Microbiology and Biotechnology
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• 제18권4호
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• pp.648-657
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• 2008

In this study, we used functional genomic strategies, proteomics and quantitative real-time (qRT)-PCR, to advance our understanding of genes associated with fumonisin production in the fungus Fusarium verticillioides. Earlier studies have demonstrated that deletion of the FCC1 gene, which encodes a C-type cyclin, leads to a drastic reduction in fumonisin production and conidiation in the mutant strain (FT536). The premise of our research was that comparative analysis of F. verticillioides wild-type and FT536 proteomes will reveal putative proteins, and ultimately corresponding genes, that are important for fumonisin biosynthesis. We isolated proteins that were significantly upregulated in either the wild type or FT536 via two-dimensional polyacrylamide gel electrophoresis, and subsequently obtained sequences by mass spectrometry. Homologs of identified proteins, e.g., carboxypeptidase, laccase, and nitrogen metabolite repression protein, are known to have functions involved in fungal secondary metabolism and development. We also identified gene sequences corresponding to the selected proteins and investigated their transcriptional profiles via quantitative real-time (qRT)-PCR in order to identify genes that show concomitant expression patterns during fumonisin biosynthesis. These genes can be selected as targets for functional analysis to further verify their roles in $FB_1$ biosynthesis.

• Journal of the Korean Wood Science and Technology
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• 제33권5호통권133호
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• pp.92-98
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• 2005

This study was performed to get the basic information concerned to the optimum culture condition of Inonotus obliquus. Several solid media, PDA, MEA and Czapek-Dox, and three liquid media were adopted for the in vitro cultivation. Some main features of the fungal morphological characteristics under cultivation conditions were observed and described. Preliminary results showed that appearance of the mycelial mat, hyphal size and substrate pigmentation differed according to the media. The PDA medium was the most favorable substrate for the growth on solid culture, followed by MEA and Czapek-Dox media. Concerned to the addition of amino acids, 5 amino acids, such as alanine, alginine, isoleucine, leucine and threonine, enhanced to the mycelial growth. Isoleucine was shown the best fungal growth. An important morphological hyphal structure for the fungus, the setae, was found in abundance and diverse its shape and size. In liquid culture, fresh potato broth was the best growth stimulant of the fungus, followed by Malt extract and potato broth. Addition of yeast extract to the liquid media had improved the biomass, but not laccase production.

• Journal of Microbiology and Biotechnology
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• 제18권11호
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• pp.1819-1825
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• 2008

Degradation and glucose production from wood chips of white pine (Pinus strobus) and tulip tree (Liriodendron tulipifera) by several white rot fungi were investigated. The highest weight losses from 4 g of wood chips of P. strobus and L. tulipifera by the fungal degradation on yeast extract-malt extract-glucose agar medium were 38% of Irpex lacteus and 93.7% of Trametes versicolor MrP 1 after 90 days, respectively. When 4 g of wood chips of P. strobus and L. tulipifera biodegraded for 30 days were treated with cellulase, glucose was recovered at the highest values of 106 mg/g degraded wood by I. lacteus and 450 mg/g degraded wood by T. versicolor. The weight loss of 10 g of wood chip of L. tulipifera by T. versicolor on the nutrient non-added agar under the nonsterile conditions was 35% during 7 weeks of incubation, and the cumulative amount of glucose produced during this period was 239 mg without cellulase treatment. The activities of ligninolytic enzymes (lignin peroxidase, manganese peroxidase, and laccase) of fungi tested did not show a high correlation with degradation of the wood chips and subsequent glucose formation. These results suggest that the selection of proper wood species and fungal strain and optimization of glucose recovery are all necessary for the fungal pretreatment of woody biomass as a carbon substrate.

• KSBB Journal
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• 제18권5호
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• pp.398-403
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• 2003

고체배양을 통해 10종의 균주 중에서 선별된 고활성 균주인 T. versicolor KCTC 16781은 100 mg/L의 6가지 염료(reactive blue 19, reactive blue 49, reactive black 5, acid black 52, reactive orange 16, and acid violet 43)를 15일 이내에 효율적으로 분해하였다. T. versicolor KCTC 16781은 액체배양에서 반응 2-3일 이내에 6가지 염료의 색도를 100% 제거시켰으며, 배양 초기에 빠른 속도로 효소를 생산하여 높은 활성을 보였다. 이로 인해 색도제거 속도가 기존의 연구에 보고된 결과들보다 우수함을 입증하였다. 서로 다른 종류의 염료분해 실험에서, 효소활성이 반응 초기에 작은 차이를 보였지만, 최대 효소활성에 도달한 후의 값이 2.0$\pm$0.5 U/mL의 범위에 들어 염료의 종류에 관계없이 비슷한 범위의 활성을 보이는 것을 확인할 수 있었다. 염료의 색도제거가 완벽하게 이루어진 후에도 효소활성은 감소하지 않았으며, 배양 말기까지 2.0 U/mL 이상의 효소활성을 유지하여 고농도의 염료를 제거할 수 있는 가능성을 보였다.

• 한국균학회지
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• 제26권1호통권84호
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• pp.91-96
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• 1998

국내에서 채집, 분리한 12종 버섯류의 균사를 대상으로 하여 멸균 증류수를 이용한 최적 보존 방법을 탐색하였다. 온도, cryoprotectant의 종류 및 농도 등의 조건을 달리하여 12개월간 보존 후 생존을 및 생장속도를 측정한 결과, 보존 온도는 상온과 $5^{\circ}C$가 최적으로 대상 균주 거의 모두가 생존하여 91.7%의 생존율을 보였다. 균사의 생장속도는 저온인 $-75^{\circ}C$에 보존하였을 때 가장 높았으며, 이 온도에서 보존시 polyethylene glycol를 cryoprotectant로 첨가하였을 때 최대의 생존율이 관찰되었다. 향기갈색깔대기버섯(H. ferrugineum)을 대상으로 하여 계대배양으로 보존한 균주와 $5^{\circ}C$에서 보존한 균주의 세포내 laccase의 활성을 조사한 결과, 효소의 활성양상이 동일하게 나타났다.

• Journal of Microbiology and Biotechnology
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• 제17권7호
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• pp.1147-1151
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• 2007

Biodegradation of endocrine-disrupting bisphenol A was investigated with several white rot fungi (Irpex lacteus, Trametes versicolor, Ganoderma lucidum, Polyporellus brumalis, Pleurotus eryngii, Schizophyllum commune) isolated in Korea and two transformants of T. versicolor (strains MrP 1 and MrP 13). I. lacteus degraded 99.4% of 50 mg/l bisphenol A in 3 h incubation and 100% in 12 h incubation. which was the highest degradation rate among the fungal strains tested. T. versicolor degraded 98.2% of 50 mg/l bisphenol A in 12 h incubation. Unexpectedly, the transformant of the Mn-repressed peroxidase gene of T. versicolor, strain MrP 1, degraded 76.5% of 50 mg/l bisphenol A in 12 h incubation, which was a lower degradation rate than wild-type T. versicolor. The removal of bisphenol A by I. lacteus occurred mainly by biodegradation rather than adsorption. Optimum carbon sources for biodegradation of bisphenol A by I. lacteus were glucose and starch, and optimum nitrogen sources were yeast extract and tryptone in a minimal salts medium; however, bisphenol A degradation was higher in nutrient-rich YMG medium than that in a minimal salts medium. The initial degradation of endocrine disruptors was accompanied by the activities of manganese peroxidase and laccase in the culture of I. lacteus.