• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.737-752
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• 2000

Wood-rotting basidiomycetous fungi are the most efficient degraders of lignin on earth. The white-rot fungus Phanerochaete chrysosporium has been used as a model microorganism in the study of enzymology and its application. Because of the ability of the white-rot fungus to degrade lignin, which has an irregular structure and large molecular mass, this fungus has also been studied in relation to degrading and mineralizing many environmental pollutants. The fungus includes an array of enzymes, such as lignin peroxidase (LiP), manganese-dependent peroxidase (MnP), cellobiose:quinone oxidoreductase, and $H_2O_2$-producing enzymes and also produces many other components of the ligninolytic system, such as veratryl alcohol (VA) and oxalate. In addition, the fungus has mechanisms for the reduction of degradation intermediates. The ligninolytic systems have been proved to provide reductive reactions as well as oxidative reactions, both of which are essential for the degradation of lignin and organopollutants. Further study on the white-rot fungus may provide many tools to both utilize lignin, the most abundant aromatic polymer, and bioremediate many recalcitrant organopollutants.

• Korean Journal of Environmental Agriculture
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• v.25 no.3
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• pp.211-216
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• 2006

The present research was undertaken to investigate the activities of ligninolytic enzymes and dye-decolorization capabilities of white-rotting fungi Coriolus hirsutus LD-1. The isolated white-rotting fungi (Coriolus hirsutus LD-1) produced laccase (16,388.9 U/L) and manganese-dependent peroxidase (19.81 U/L) but it did not produce lignin peroxidase. When the isolated fungi was incubated with the treatment of dyes for 8 days, the rates of decolorization of remazol brilliant blue R and bromophenol blue were 70.2% and 98%, respectively. The activity for manganese-dependent peroxidase was low, whereas that for laccase was very high. Moreover, the laccase was more effective to decolor when compared to manganese-dependent peroxidase. The results suggested that laccase of Coriolus hirsutus LD-1 might be playing an important role in the decolorization of the dyes.

• BMB Reports
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• v.32 no.5
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• pp.486-491
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• 1999

An engineered cDNA from Phanerochaete chrysosporium encoding both the mature and propeptide-sequence regions of lignin peroxidase H2 (Lip H2) was overexpressed in Escherichia coli BL21 (DE3) to evaluate its catalytic characteristics and potential application as a pollution scavenger. All expressed proteins were aggregated in an inactive inclusion body, which might be due to inherent disulfide bonds. Active enzyme was obtained by refolding with glutathione-mediated oxidation in refolding solution containing $Ca^{2+}$, heme, and urea. Propeptide-sequence region was not processed as evidenced by N-terminal sequence analysis. Recombinant Lip H2 (rLip H2) had the same physical properties of the native protein but differed in the $K_{cat}$. Catalytic efficiency ($k_{cat}/K_m$) of rLip H2 was slightly higher than that of the native enzyme. In order to express an active protein, fusion systems with thioredoxin or Dsb A, which have disulfide isomerase activity, were used. The fused proteins expressed by the Dsb A fusion vector were aggregated, whereas half of the thioredoxin fusion proteins were recovered as a soluble form but still catalytically inactive. These results suggest that Lip H2 may not be expressed as an active enzyme in Escherichia coli although the activity can be recovered by in vitro refolding.

• Journal of Microbiology and Biotechnology
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• v.8 no.2
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• pp.129-133
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• 1998

The white-rot fungi Phanerochaete chrysosporium ATCC 24725, Pleurotus ostreatus ATCC 32783, Lentinus edodes ATCC 24462, and Trametes versicolor ATCC 42530 were studied for their ability to degrade lignin, phenanthrene, and anthracene. Lignin in rice-straw was degraded by 14.4, 28.73, and 33.88% by P. chrysosporium, T. versicolor, and P. ostreatus, respectively. Approximately 12% and 83% of phenanthrene was degraded in 1 and 5 days, respectively, when the pre-grown mycelIium matrix of P. ostreatus. was incubated with 10 ppm of phenanthrene in modified Kirk's medium (nitrogen limited) at $25^{\circ}C$. Approximately 2%> and 61% of phenanthrene was degraded when the phenanthrene concentration was increased to 30 ppm. Similar trends were observed with phenanthrene using P. chrysosporium. Mycelial growth of T. versicolor was less inhibited at 30 ppm phenanthrene than for P. ostreatus and P. chrysosporium. Better degradation of phenanthrene by T. versicolor may be attributed to better mycelium growth. One hundred percent of 15 ppm anthracene was degraded in 10 days by both P. chrysosporium and T. versicolor. 40 ppm anthracene inhibited the mycelial growth of P. chrysosporium. lignin peroxidase activity, which was previously reported to be involved in initial phenanthrene oxidation, was also detected from the culture broth of the strains tested. The rates of lignin peroxidase production in the cultures were not consistent with the rate of PAH hydrolysis during incubation.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.223-229
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• 2010

In this study diverse dehydrogenative polymers (DHPs) were synthesized with three precursors of native lignin [p-coumaryl alcohol (PCA), coniferyl alcohol (CA), sinapyl alcohol (SA)] in the presence of horseradish peroxidase (HRP, EC. 1.11.1.7)/$H_2O_2$. To compare the structural features between DHPs and native lignin, the DHPs as well as pine/poplar milled wood lignins were simultaneously subjected to gel permeation chromatography (GPC) to determine average molecular weights and derivatization followed by reductive cleavage (DFRC) to investigate the frequency of ${\beta}$-O-4 linkage. The highest yield of DHP was measured to 71% when CA was solely injected (G-DHP) and the yield of H-DHP was 42%. However, single injection of SA could not form any polymer in this system. The average molecular weights of DHPs were ranged between 3,000~4,700, which were only 1/2 fold compared with that of pine MWL (G-type lignin: Mw 7,340) and 1/3 scale compared with that of poplar MWL (GS-type lignin: Mw 13,250). DFRC analysis revealed that the formation of ${\beta}$-O-4 linkage during dehydrogenative polymerization was the highest in the GS-DHP with ca. 502 ${\mu}mol$/g, which was, however, remained to only 50% compared to that in poplar MWL (1107 ${\mu}mol$/g). The ${\beta}$-O-4 linkage was estimated to ca. 286 ${\mu}mol$/g In the G-DHP, which was twice as much as that of H-DHP(127 ${\mu}mol$/g). Similar to GS-DHP, only half amount of ${\beta}$-O-4 linkage, compared to pine MWL, was formed during in vitro polymerization of CA by horseradish peroxidase/$H_2O_2$.

• 한국균학회소식:학술대회논문집
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• 2014.05a
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• pp.43-43
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• 2014

White rot fungi have been useful source of enzymes for the degradation of environmental pollutants including polycyclic aromatic hydrocarbons (PAHs) and synthetic dyes. PAHs are widespread organic compounds present in fossil fuels and are routinely generated by incomplete fuel combustion. PAHs are some of the major toxic pollutants of water and soil environments. Synthetic dyes are major water-pollutants, which are toxic to organisms in water environments and interfere photosynthesis of water plants. Removal of PAHs and synthetic dyes has been of interests in the environmental science especially in the environmental microbiology. Mushrooms are fungal groups that function as primary degraders of wood polyphenolic lignin. The ligninolytic enzymes produced by mushroom, including manganese peroxidase, lignin peroxidase, and laccase, mediate the oxidative degradation of lignin. The catalytic power of these enzymes in the degradation of aromatic ring compounds has been sought for the degradation of various organic compounds. In this project, we have screened 60 wild mushroom strains for their degradation activity against two representative PAHs, naphthalene and anthracene, and five aromatic dyes, including alizarin red S, crystal violet, malachite green, methylene blue, rose bengal. The degradation of PAHs was measured by GC while the decolorization of dyes was measured by both UV spectrophotometer and HPLC. As results, 9 wild mushroom strains showed high activity in degradation of PAHs and textile dyes. We also describe the secretive enzyme activities, the transcription levels, and cloning of target genes. In conjunction with this, activities of degradative enzymes, including laccase, lignin peroxidase, and Mn peroxidase, were measured in the liquid medium in the presence of PAHs and dyes. Our results showed that the laccase activity was directed correlated with the degradation, indicating that the main enzyme acts on PAHs and dyes is the laccase. The laccase activity was further simulated by the addition of $Cu^{2+}$ ion. Detailed studies of the enzyme system should be sought for future applications.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.53-61
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• 1999

Effects of culture conditions and Mn(II) addition were investigated for production of extracellular manganese peroxidase by lignin-degrading fungus LSK-27, Nitrogen source was shown to more influence the production of extracellular manganese peroxidase by LSK-27 than carbon source. When peptone or yeast extract as nitrogen source was added, high MnP activity was obtained. Especially, nitrogen-sufficient culture condition was effective in MnP activity, showing significantly increase up to 1.0% peptone concentration, but carbon-sufficient was not. Mn(II) was shown to strongly induce the MnP production in culture fluids of LSK-27. Increase of MnP actiyity was obeserved up to addition of 100ppm Mn(II), and over this Mn(II) concentration appeared to be inhibitory. The highest level of MnP activity was attained when Mn(II) was added after 2 day incubation.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.759-763
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• 2000

Cell-free culture broth of Phanerochaete chrysosporium has been adopted to biologically degrade 2,4,5-trichlorophenol. Two different medium compositions of nitrogen-sufficient and nitrogen-limited were compared for their distribution of isozymes, activity of lignin peroxidase, and production of oxalate. The two different culture broths were tested for their ability to degrade 2,4,5-trichlorophenol, and the biodegradation efficiency was estimated in terms of the disappearance of 2,4,5-trichlorophenol. The degradation efficiency for the nitrogen-limited culture broth was higher than that of the nitrogen-sufficient culture broth, since the nitrogen-limited culture broth induced lignin peroxidases (LiPs) and manganese peroxidases (MnPs), and contained sufficient oxalate for producing necessary radicals. Finally, the possible mechanism of 2,4,5-CP degradation using the nitrogen-limited culture broth was proposed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.2
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• pp.8-14
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• 1999

A screening has been performed to find hyper-ligninolytic fungi, which degtrade beech and pine lignin extensively in order to broaden the understanding of the ligninolytic enzymes elaborated by various white-rot fungi. One hundred and twenty two ligninolytic strains were selected from decayed woods with a selective medium for screening ligninolytic wood-rotting fungi. Two of them, Phanerochaete sordida YK-624 and YK-472, showed much higher ligninolytic activity and selectivity in beech-wood degradation than typical lignin-degrading fungi, phanerochaete chrysosporium and Coriolus versicolor. They also degraded birch dioxane lignin and residual lignin in unbleached kraft pulp(UKP) much more extensively than P. chrysosporium and C. versicolor. During fungal treatment of beech wood-powder, the fungus strain P. sordida YK-624 showed higher activity of extracellular manganese peroxidase (MnP) in the medium than P. chrysosporium. It also showed MnP activity, which would not be lignin peroxidast during treatment of oxygen-bleached kraft pulp(OKP) and under enzyme-inducing conditin.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.877-880
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• 1999

Over 50 morphologically distinctive soil Streptomyces were isolated from various Jocations in the Yongin area in Korea and visually screened for dye-decoloring activities on an agar plate. Two Streptomyces species (AD001 and ND002) showed strong dye-decoloring activities on the plate containing congo-red and new-fuchin dyes, respectively. Also, the liquid culture supernatants of these species showed 2,4-dicholophenol (DCP) oxidation activities only in the presence of hydrogen peroxide, a characteristic of Actinomycetes lignin-peroxidase (ALiP)-P3 isoform found in dye-degrading S. viridosporus T7A and S. badius 252. Based on their dye-decoloring capabilities and the 2,4-DCP oxidation kinetic data, it is suggested that these Streptomyces secrete not-yet-characterized extracelluar enzyme(s), whose activities are very similar to the ALiP-P3 enzyme.