粗毛栓菌的木质纤维素降解酶及其基因克隆
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摘要
木质纤维素主要由纤维素、半纤维素和木质素组成,是自然界中广泛存在的可再生的数量巨大的生物质资源。微生物来源的纤维素酶和半纤维素酶可分别水解纤维素和半纤维素。由于木质素结构高度复杂,从而使植物生物质的利用受到很大限制。白腐真菌所产生的木质素降解酶可有效地分解木质素和芳香族污染物,因而在生物制浆、纸浆的生物漂白和环境保护等方面具有重要的研究价值和应用前景。黄孢原毛平革菌(Phanerochaete chrysosporium)作为木质素生物降解模式种,一直是被广泛研究的对象,但它的木质素降解酶活性并不令人满意,如,它几乎不产生漆酶,而漆酶却是木质素酶系的重要成员。因此,选育高产木质素降解酶菌株、克隆和高效表达木质素降解酶cDNA是研究木质素降解的主要研究内容。粗毛栓菌(Trametes gallica)是一种白腐担子菌,在我国分布广泛,是杨木的一种主要生物降解者。已有研究表明,该菌具有较强的降解木质纤维素的能力。本论文以T.gallica作为出发菌,在以下4个方面进行了研究工作:(1)研究了其产生木质纤维素降解酶的条件;(2)对其部分木质素降解酶进行了分离纯化和性质分析;(3)利用基因芯片技术将其与模式菌株的差异表达基因做了比较和分析;(4)克隆了锰过氧化物酶cDNA和热激蛋白cDNA。取得如下研究结果:
第一,采用不同发酵条件,研究了粗毛栓菌产过氧化物酶和漆酶的特点。结果表明,高碳低氮(2.2mmol/L)-浅层液体静置培养有利于粗毛栓菌产生锰过氧化物酶。例如,以葡萄糖作碳源,培养12d时的MnP活力达到36.9U/L。相反,漆酶产量在低碳高氮-振荡培养条件下是最高的。无论是高氮还是低氮营养,浅层静置培养的T.gallica都仅能产少量的漆酶。在以苯丙氨酸作氮源的
Lignocellulose is composed of cellulose, hemicellulose and lignin, and the most abundant and renewable bio-resource in nature. Cellulose and hemicellulose can be enzymatically hydrolyzed by cellulase and hemicellulase from microorganisms, respectively. However, the structure heterogeneity and recalcitrance of lignin greatly retard the efficient utilization of plant biomass. The white-rot fungi secrete ligninolytic enzymes to oxidatively decompose lignin and aromatic pollutants. These enzymes are greatly potential in bio-pulping, bio-bleaching of pulp and treatment of environmental pollutants, etc. Phanerochaete chrysosporium, a model microorganism in studying lignin bio-degradation, has been extensively studied, but it produces low ligninolytic enzymes and little laccase, which is the important member of ligninolytic enzyme system. Therefore, the screening of strains with high yield of ligninolytic enzymes, the cloning and the high efficient expression of ligninolytic enzyme genes are important research aspects in the lignin biodegradation. White-rot basidiomycete Trametes gallica is one of the main bio-degraders of poplar in China. Our previous study has proved its strong capacity to degrade lignocellulose. Using T. gallica as a donor strain, studies were carried out in the following 4 aspects: (1) production of lignocellulolytic enzymes by T. gallica; (2) purification and characterization of some ligninolytic enzymes; (3) comparison and analysis of the differentially expressed genes between T. gallica and the model strain P. chrysosporium by gene chip; (4) cloning of MnP cDNA and heat shock protein
cDNA. The corresponding results obtained are as follows:Firstly, several procedures have been employed for growing T. gallica to produce lignocellulose-degrading enzymes. The results showed that nitrogen-limited nutrition (2.2 mmol/L) and shallow stationary cultivation favored production of extracellular MnP with activity of 36.9 U/L in glucose medium for 12d. However, laccase levels observed in high-nitrogen (22 mmol/L) agitated cultures were much greater than those found in low-nitrogen. Furthermore, only low laccase activity could be obtained under shallow stationary cultivation no matter whatever high or low nitrogen was used. MnP activity reached 118.1 U/L when T. gallica was grown in a low-nitrogen culture containing phenylalanine, hemicellulose and cellulose. The experiments showed that NH/ plays an important role in inducing production of MnP and laccase of the fungus. Results indicate that T. gallica produces a series of the lignocellulolytic enzymes (cellulase, hemicellulase, laccase, MnP and LiP), and needs sufficient nitrogen nutrient to produce all the enzymes during solid-state fermentation of wheat straw. In the presence of high concentration of nitrogen and Mn2+, the resulting 396.7 U/L of MnP in soaking fluid of the solid culture (with high concentration of nitrogen and Mn2+) was obtained, corresponding to 2.0 U per gram of straw powder.Secondly, one active component with cellulae, xylanase, laccase, MnP and LiP activity, was obtained by Sepharose-Q Fast Flow chromatography. By further fraction on Sephadex G-100 and recovery through native-polyacrylamid gel electrophoresis (PAGE), a purified MnP and a laccase were separately obtained. SDS-PAGE and isoelectric focusing (IEF) were used to evaluated molecular weight and isoelectric point (pi) of protein, respectively. The purified MnP had a molecular weight of 35.7 kDa and a pi of pH 2.8, and the laccase, 58.4 kDa, and pi 3.2, respectively. The result showed that MnP has a maximum absorbance at 407 run, optimal pH 5.25 and reaction temperature of 35°C. The laccase showed maximum activity at optimal pH 3.5 and 35°C respectively. A new tank for detection of protein pi without suing ampholytes was designed and constructed. The pi of bovine serum albumin was evaluated as pH 4.7 by the new mothod, and equal to that by IEF. This
preliminarily verified the possibility of the new method for detection of pi of ampholytes.Thirdly, by cDNA microarray hybridization, the differentially expressed geneS of T. gallica cultivated in nitrogen-limited medium at different times were studied; Two total-RNA isolates of T. gallica cultured for 5d and 12d on the N-limited medium were extracted. Fluorescent dye- (cy-5- and cy-3-dCTP) labeled cDNA was produced through single primer amplification reaction. The labeled cDNA was hybridized to the cDNA microarray, which contained 2,596 cDNA fragments froman SSH (suppression subtractive hybridization) library of P. chrysosporium grown onishallow N-limited culture for 2 and 3 days. The results showed that there were 17^ positive clones detected on the microarray. There are 95.9% of the positive clones with a ratio (intensity of labeled 12d cDNA/intensity of labeled 5d cDNA) from 0.5 to 2.0. However, only 3 and 4 clones with the ratio over 2.0 and lower than 0.5 wer$ found, respectively, corresponding to 5d and 12d cultures of T. gallica. One hundred and twenty-two clones were randomly selected and sequenced, of which 118 clones could be perfectly located in the genome of P. chrysosporium. These clones can be grouped into 47 genes, among them, the function of 24 genes have been known, including 19 house-keeping genes. The result indicates that there is obvious sequence difference and far relative between these two fungi. Two interesting clones have been obtained from homoiogy comparison, one corresponding to a fragment of peroxidase ipoB gene of P. chrysosporium and the other encoding a sort of heat shock protein.Fourthly, a pair of specific primers corresponding to the conserved sequences of mature MnP cDNAs of T. versicolor and P. chrysosporium were designed and use<￡ to amplify MnP cDNA of T. gallica with PCR reaction, in which the total cDNA$ were used as templates. An MnP cDNA fragment with 580 bp was obtained and ha$ an open reading frame encoding a peptide with 193 amino acid residues and 20.5 kDa of molecular weight. There was an obvious codon usage preference and more than 90% of homoiogy with one MnP sequence of T. versicolor. Similarly, a pair of specific primers corresponding to the sequence of mature heat-shock protein (HSP) cDNA of T. versicolor was designed and used to amplify HSP cDNA from T. gallica
using RT-PCR reaction, in which the total RNAs were used as templates. A cDNA fragment with 848 bp was obtained and encodes a mature peptide with 256 amino acid residues and 28.4 kDa of molecular weight. The deduced amino acid sequence shares 90% of homology with that of HSP from T. versicolor fddl23b. The strongest codon usage preference has been found for codon CAA of Gin, AAG of Lys and TGT of Cys, whose usage frequency reached 100%.
第一,采用不同发酵条件,研究了粗毛栓菌产过氧化物酶和漆酶的特点。结果表明,高碳低氮(2.2mmol/L)-浅层液体静置培养有利于粗毛栓菌产生锰过氧化物酶。例如,以葡萄糖作碳源,培养12d时的MnP活力达到36.9U/L。相反,漆酶产量在低碳高氮-振荡培养条件下是最高的。无论是高氮还是低氮营养,浅层静置培养的T.gallica都仅能产少量的漆酶。在以苯丙氨酸作氮源的
Lignocellulose is composed of cellulose, hemicellulose and lignin, and the most abundant and renewable bio-resource in nature. Cellulose and hemicellulose can be enzymatically hydrolyzed by cellulase and hemicellulase from microorganisms, respectively. However, the structure heterogeneity and recalcitrance of lignin greatly retard the efficient utilization of plant biomass. The white-rot fungi secrete ligninolytic enzymes to oxidatively decompose lignin and aromatic pollutants. These enzymes are greatly potential in bio-pulping, bio-bleaching of pulp and treatment of environmental pollutants, etc. Phanerochaete chrysosporium, a model microorganism in studying lignin bio-degradation, has been extensively studied, but it produces low ligninolytic enzymes and little laccase, which is the important member of ligninolytic enzyme system. Therefore, the screening of strains with high yield of ligninolytic enzymes, the cloning and the high efficient expression of ligninolytic enzyme genes are important research aspects in the lignin biodegradation. White-rot basidiomycete Trametes gallica is one of the main bio-degraders of poplar in China. Our previous study has proved its strong capacity to degrade lignocellulose. Using T. gallica as a donor strain, studies were carried out in the following 4 aspects: (1) production of lignocellulolytic enzymes by T. gallica; (2) purification and characterization of some ligninolytic enzymes; (3) comparison and analysis of the differentially expressed genes between T. gallica and the model strain P. chrysosporium by gene chip; (4) cloning of MnP cDNA and heat shock protein
cDNA. The corresponding results obtained are as follows:Firstly, several procedures have been employed for growing T. gallica to produce lignocellulose-degrading enzymes. The results showed that nitrogen-limited nutrition (2.2 mmol/L) and shallow stationary cultivation favored production of extracellular MnP with activity of 36.9 U/L in glucose medium for 12d. However, laccase levels observed in high-nitrogen (22 mmol/L) agitated cultures were much greater than those found in low-nitrogen. Furthermore, only low laccase activity could be obtained under shallow stationary cultivation no matter whatever high or low nitrogen was used. MnP activity reached 118.1 U/L when T. gallica was grown in a low-nitrogen culture containing phenylalanine, hemicellulose and cellulose. The experiments showed that NH/ plays an important role in inducing production of MnP and laccase of the fungus. Results indicate that T. gallica produces a series of the lignocellulolytic enzymes (cellulase, hemicellulase, laccase, MnP and LiP), and needs sufficient nitrogen nutrient to produce all the enzymes during solid-state fermentation of wheat straw. In the presence of high concentration of nitrogen and Mn2+, the resulting 396.7 U/L of MnP in soaking fluid of the solid culture (with high concentration of nitrogen and Mn2+) was obtained, corresponding to 2.0 U per gram of straw powder.Secondly, one active component with cellulae, xylanase, laccase, MnP and LiP activity, was obtained by Sepharose-Q Fast Flow chromatography. By further fraction on Sephadex G-100 and recovery through native-polyacrylamid gel electrophoresis (PAGE), a purified MnP and a laccase were separately obtained. SDS-PAGE and isoelectric focusing (IEF) were used to evaluated molecular weight and isoelectric point (pi) of protein, respectively. The purified MnP had a molecular weight of 35.7 kDa and a pi of pH 2.8, and the laccase, 58.4 kDa, and pi 3.2, respectively. The result showed that MnP has a maximum absorbance at 407 run, optimal pH 5.25 and reaction temperature of 35°C. The laccase showed maximum activity at optimal pH 3.5 and 35°C respectively. A new tank for detection of protein pi without suing ampholytes was designed and constructed. The pi of bovine serum albumin was evaluated as pH 4.7 by the new mothod, and equal to that by IEF. This
preliminarily verified the possibility of the new method for detection of pi of ampholytes.Thirdly, by cDNA microarray hybridization, the differentially expressed geneS of T. gallica cultivated in nitrogen-limited medium at different times were studied; Two total-RNA isolates of T. gallica cultured for 5d and 12d on the N-limited medium were extracted. Fluorescent dye- (cy-5- and cy-3-dCTP) labeled cDNA was produced through single primer amplification reaction. The labeled cDNA was hybridized to the cDNA microarray, which contained 2,596 cDNA fragments froman SSH (suppression subtractive hybridization) library of P. chrysosporium grown onishallow N-limited culture for 2 and 3 days. The results showed that there were 17^ positive clones detected on the microarray. There are 95.9% of the positive clones with a ratio (intensity of labeled 12d cDNA/intensity of labeled 5d cDNA) from 0.5 to 2.0. However, only 3 and 4 clones with the ratio over 2.0 and lower than 0.5 wer$ found, respectively, corresponding to 5d and 12d cultures of T. gallica. One hundred and twenty-two clones were randomly selected and sequenced, of which 118 clones could be perfectly located in the genome of P. chrysosporium. These clones can be grouped into 47 genes, among them, the function of 24 genes have been known, including 19 house-keeping genes. The result indicates that there is obvious sequence difference and far relative between these two fungi. Two interesting clones have been obtained from homoiogy comparison, one corresponding to a fragment of peroxidase ipoB gene of P. chrysosporium and the other encoding a sort of heat shock protein.Fourthly, a pair of specific primers corresponding to the conserved sequences of mature MnP cDNAs of T. versicolor and P. chrysosporium were designed and use<￡ to amplify MnP cDNA of T. gallica with PCR reaction, in which the total cDNA$ were used as templates. An MnP cDNA fragment with 580 bp was obtained and ha$ an open reading frame encoding a peptide with 193 amino acid residues and 20.5 kDa of molecular weight. There was an obvious codon usage preference and more than 90% of homoiogy with one MnP sequence of T. versicolor. Similarly, a pair of specific primers corresponding to the sequence of mature heat-shock protein (HSP) cDNA of T. versicolor was designed and used to amplify HSP cDNA from T. gallica
using RT-PCR reaction, in which the total RNAs were used as templates. A cDNA fragment with 848 bp was obtained and encodes a mature peptide with 256 amino acid residues and 28.4 kDa of molecular weight. The deduced amino acid sequence shares 90% of homology with that of HSP from T. versicolor fddl23b. The strongest codon usage preference has been found for codon CAA of Gin, AAG of Lys and TGT of Cys, whose usage frequency reached 100%.
引文
1.孙迅,任少亭,毕瑞明.2002.粗毛栓菌降解麦草木质纤维素的实验研究.微生物学杂志.22(1):24-26.
2.谢君.2001.白腐菌木质纤维素降解酶产生条件及其基因的克隆、突变和表达研究.四川大学博士学位论文.
3. Borbacheva, I. V. and N. A. Radionova. 1977. Action pattern of endo-1, 4-beta-xylanase from Aspergillus niger str. 14 on xylan and xylooligosaccharides. Biochim. Biophys. Acta. 484(1): 94-102.
4. Bourbonnais, R. and M. G. Paice. 1990. Oxidation of non-phenolic substrates: An expanded role for laccase in lignin biodegradation. FEBS Lett. 267: 99-102.
5. Dhawale, S. S. 1993. Is an activator protein-2-like transcription factor involved in regulating gene expression during nitrogen limitation in fungi? Appl. Environ. Microbiol. 59(7): 2335-2338.
6. D'Souza, T. M., C. S. Merritt and C. A. Reddy. 1999. Lignin-modifying enzymes of the white rot basidiomycete Ganoderma lucidum. Appl. Environ. Microbiol. 65(12): 5307-13.
7. Elisashvili, V. I., T. S. Khardziani and N. D. Tsiklauri. 1999. Cellulase and xylanase activities in higher basidiomycetes. Biochemistry (Mosc). 64(6): 718-22.
8. Eriksson, K.-E., R. A. Blanchette and P. Ander. 1990. Biodegradation of lignin. In: Microbial and Enzymatic Degradation of Wood and Wood Components. pp 225-334. Springer-Verlag, Berlin.
9. Faison, B. D. and T. K. Kirk. 1985. Factors involved in the regulation of a ligninase activity in Phanerochaete chrysosporium. Appl. Environ. Microbiol. 49: 299-304.
10. Fu, S. Y., H. S. Yu and J. A. Buswell. 1997. Effect of nutrient nitrogen and manganese on manganese peroxidase and laccase production by Pleurotus sajor-caju. FEMS Microbiol. Lett. 147: 133-137.
11. Glenn, J. K. and M. Gold. 1985. Purification and characterization of an extracellular Mn(Ⅱ)-dependent peroxidase from the lignin degrading basidiomycete Phanerochaete chrysosporium. Arch. Biochem. Biophys. 242: 329-341.
12. Glenn, J. K., M. A. Morgan, M. B. Mayfield, M. Kuwahara and M. H. Gold. 1983. An extracellular H_2O_2 requiring enzyme preparation involved in lignin biodegradation by the white rot basidiomycete Phanerochaete chrysosporium. Biochem. Biophys. Res. Commun. 114:1077-1083.
13. Goren, R. and M. Huberman. 1976. A simple and sensitive staining method for the detection of cellulase isozymes in polyacrylamide gels. Anal. Biochem. 75: 1-8.
14. Jager, A., S. Croan and T. K. Kirk. 1985. Production of ligninases and degradation of lignin in agitated submerged cultures of Phanerochaete chrysosporiwn. Appl. Environ. Microbiol. 50: 1274-1278.
15. Johansson, T. and P. O. Nyman. 1993. Isoenzymes of lignin peroxidase and manganese peroxidase from the white-rot basidiomycete Trametes versicolor. I. Isolation of enzyme forms and characterization of physical and catalytic properties. Arch. Biochem. Biophys. 300: 49-56.
16. Kanda, T., K. Wakabayashi and K. Nisizawa. 1976. Xylanase activity of an endo-cellulase of carboxymethyl-cellulase type from Irpex lactens (Polyporus tulipiferae). J. Biochem. (Tokyo). 79(5): 989-995.
17. Kirk, T. K. and R. L. Farrell. 1987. Enzymatic combustion: the microbial degradation of lignin. Annu. Rev. Microbiol. 41, 465-505.
18. Kirk, T. K., S. Croan and M. Tien. 1986. Production of multiple ligninases by Phanerochaete chrysosporiwn: effect of selected grown conditions and use of a mutant strain. Enzyme Microb. Technol. 8: 27-32.
19. Laemmli, U. K. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T_4. Nature. 227: 680-685.
20. Li, D., M. Alic and M. H. Gold. 1994. Nitrogen regulation of lignin peroxidase gene transcription. Appl. Environ. Microbiol. 60 (9): 3447-3449.
21. MacKenzie, C. R. and R. E. Williams. 1984. Detection of cellulase and xylanase activity in isoelectric-focused gels using agar substrate gels supported on plastic film. Can. J. Microbiol. 30: 1522-1525.
22. Manji, S. and A. Ishihara. 2003. Screening of tetrachlorodibenzo- p-dioxin-degrading fungi capable of producing extracellular peroxidases under various conditions. Appl. Microbiol. Biotechnol. [Epub ahead of print].
23. Martinez, A. T., J. Ruiz and M. J. Martinez. 1994. Influence of Mn concentration and N source on the production of ligninolytic enzymes in liquid cultures of Pleurotus species. P. 134. In Abstracts of the 5th International Mycological Congress, 1994. Vancouver. British Columbia, Canada.
24. Martinez, A. T., S. Camarero, F. Guillen, A. Gutierrez, C. Munoz, E. Varela, M. J. Martinez, J. M. Barrasa, K. Ruel and J. M. Pelayo. 1994. Progress in biopulping of non-woody materials: chemical, enzymatic and ultrastructural aspects of wheat straw delignification with ligninolytic fungi from the genus Pleurotus. FEMS Microbiol. Rev. 13: 265-274.
25. Michael, H G. and J. K. Glenn. 1988. Manganese peroxidase from Phanerochaete chrysosporium. Method Enzymol. 161B: 258-264.
26. Miller, G. L. 1959. Use of dinitrosalicylic acid reagent for determination of reducing sugar. Anal. Chem. 31 (3): 426-428.
27. Munoz, C, F. Guillen, A. T. Martinez and M. J. Martinez. 1997. Induction and characterization of laccase in the ligninolytic fungus Pleurotus eryngii. Curr. Microbiol. 34: 1-5.
28. Panbangred, W., A. Shinmyo, S. Kinoshita and H. Okada. 1983. Purification and properties of endoxylanase produced by Bacillulus pumilus. Agric. Biol. Chem. 47: 957-963.
29. Paszczynski, A., V. Huynh and R. Crawford. 1985. Enzymatic activities of an extracellular Mn-dependent peroxidase from Phanerochaete chrysosporium . FEMS Microbiol. Lett. 29: 37-41.
30. Pease, E. A., S. D. Aust and M. Tien. 1991. Heteroiogous expression of active manganese peroxidase from Phanerochaete chrysosporium using the Baculovirus expression system. Biochem. Biophys. Res. Commun. 179: 897-903.
31. Royer, J. C. and J. P. Nakas. 1990. Simple, sensitive zymogram technique for detection of xylanase activity in polyacrylamide gels. Appl. Environ. Microbiol. 56: 1516-1517.
32. Ruttimann-Johnson, C, D. Cullen and R. T. Lamar. 1994. Manganese peroxidases of the white rot fungus Phanerochaete sordida. Appl. Environ. Microbiol. 60(2): 599-605.
33. Sawyer, N. A., S. M. Chambers and J. W. Cairney. 2003. Utilisation of inorganic and organic nitrogen sources by Amanita species native to temperate eastern Australia. Mycol. Res. 107(Pt 4): 413-420.
34. Schoemaker, H. E. and M. S. A. Leisola. 1990. Degradation of lignin by Phanerochaete chrysosporium. J. Biotech. 13: 101-109.
35. Shuttleworth, K. L., L. Postie and J.-M. Bollag. 1986. Production of induced laccase by the fungus Rhizoctonia praticola. Can. J. Microbiol. 32: 867-870.
36. Singh, R. P., H. S. Garcha and P. K. Khanna. 1988. Laccase production by Pleurotus spp. Indian J. Microbiol. 28:38-41.
37. Tekere, M., R. Zvauya and J. S. Read. 2001. Ligninolytic enzyme production in selected sub-tropical white rot fungi under different culture conditions. J. Basic Microbiol. 41(2): 115-29.
38. Tien, M. and T. K. Kirk. 1983. Lignin degrading enzyme from the hymenomycete Phanerochaete chrysosporium burds. Science. 221: 661-663.
39. Tien, M. and T. K. Kirk. 1988. Lignin peroxidase of Phanerochaete chrysosporium. Methods Enzymol. 161:238-249.
40. Valmaseda, M., M. J. Martinez and A. T. Martinez. 1991. Kinetics of wheat straw solid-state fermentation with Trametes versicolor and Pleurotus ostreotus — lignin and polysaccharide alteration and production of related enzymatic activities. Appl. Microbiol. Biotechnol. 35: 817-823.
41. Vares, T., M. Kalsi and A. Hatakka. 1995. Lignin peroxidases, manganese peroxidases, and other ligninolytic enzymes produced by Phlebia radiata during solid-state fermentation of wheat straw. Appl. Environ. Microbiol. 61: 3515-3520.
42. Wolfenden, B. S. and R. L. Willson. 1982. Radical-cations as reference chromogens in kinetics studies of one-electron transfer reactions: pulse radiolysis studies of 2,2-azinobis (3-ethylbenzothiazoline-6-sulphonate). J. Chem. Soc. Perkin Trans. II. 1982.
2.谢君.2001.白腐菌木质纤维素降解酶产生条件及其基因的克隆、突变和表达研究.四川大学博士学位论文.
3. Borbacheva, I. V. and N. A. Radionova. 1977. Action pattern of endo-1, 4-beta-xylanase from Aspergillus niger str. 14 on xylan and xylooligosaccharides. Biochim. Biophys. Acta. 484(1): 94-102.
4. Bourbonnais, R. and M. G. Paice. 1990. Oxidation of non-phenolic substrates: An expanded role for laccase in lignin biodegradation. FEBS Lett. 267: 99-102.
5. Dhawale, S. S. 1993. Is an activator protein-2-like transcription factor involved in regulating gene expression during nitrogen limitation in fungi? Appl. Environ. Microbiol. 59(7): 2335-2338.
6. D'Souza, T. M., C. S. Merritt and C. A. Reddy. 1999. Lignin-modifying enzymes of the white rot basidiomycete Ganoderma lucidum. Appl. Environ. Microbiol. 65(12): 5307-13.
7. Elisashvili, V. I., T. S. Khardziani and N. D. Tsiklauri. 1999. Cellulase and xylanase activities in higher basidiomycetes. Biochemistry (Mosc). 64(6): 718-22.
8. Eriksson, K.-E., R. A. Blanchette and P. Ander. 1990. Biodegradation of lignin. In: Microbial and Enzymatic Degradation of Wood and Wood Components. pp 225-334. Springer-Verlag, Berlin.
9. Faison, B. D. and T. K. Kirk. 1985. Factors involved in the regulation of a ligninase activity in Phanerochaete chrysosporium. Appl. Environ. Microbiol. 49: 299-304.
10. Fu, S. Y., H. S. Yu and J. A. Buswell. 1997. Effect of nutrient nitrogen and manganese on manganese peroxidase and laccase production by Pleurotus sajor-caju. FEMS Microbiol. Lett. 147: 133-137.
11. Glenn, J. K. and M. Gold. 1985. Purification and characterization of an extracellular Mn(Ⅱ)-dependent peroxidase from the lignin degrading basidiomycete Phanerochaete chrysosporium. Arch. Biochem. Biophys. 242: 329-341.
12. Glenn, J. K., M. A. Morgan, M. B. Mayfield, M. Kuwahara and M. H. Gold. 1983. An extracellular H_2O_2 requiring enzyme preparation involved in lignin biodegradation by the white rot basidiomycete Phanerochaete chrysosporium. Biochem. Biophys. Res. Commun. 114:1077-1083.
13. Goren, R. and M. Huberman. 1976. A simple and sensitive staining method for the detection of cellulase isozymes in polyacrylamide gels. Anal. Biochem. 75: 1-8.
14. Jager, A., S. Croan and T. K. Kirk. 1985. Production of ligninases and degradation of lignin in agitated submerged cultures of Phanerochaete chrysosporiwn. Appl. Environ. Microbiol. 50: 1274-1278.
15. Johansson, T. and P. O. Nyman. 1993. Isoenzymes of lignin peroxidase and manganese peroxidase from the white-rot basidiomycete Trametes versicolor. I. Isolation of enzyme forms and characterization of physical and catalytic properties. Arch. Biochem. Biophys. 300: 49-56.
16. Kanda, T., K. Wakabayashi and K. Nisizawa. 1976. Xylanase activity of an endo-cellulase of carboxymethyl-cellulase type from Irpex lactens (Polyporus tulipiferae). J. Biochem. (Tokyo). 79(5): 989-995.
17. Kirk, T. K. and R. L. Farrell. 1987. Enzymatic combustion: the microbial degradation of lignin. Annu. Rev. Microbiol. 41, 465-505.
18. Kirk, T. K., S. Croan and M. Tien. 1986. Production of multiple ligninases by Phanerochaete chrysosporiwn: effect of selected grown conditions and use of a mutant strain. Enzyme Microb. Technol. 8: 27-32.
19. Laemmli, U. K. 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T_4. Nature. 227: 680-685.
20. Li, D., M. Alic and M. H. Gold. 1994. Nitrogen regulation of lignin peroxidase gene transcription. Appl. Environ. Microbiol. 60 (9): 3447-3449.
21. MacKenzie, C. R. and R. E. Williams. 1984. Detection of cellulase and xylanase activity in isoelectric-focused gels using agar substrate gels supported on plastic film. Can. J. Microbiol. 30: 1522-1525.
22. Manji, S. and A. Ishihara. 2003. Screening of tetrachlorodibenzo- p-dioxin-degrading fungi capable of producing extracellular peroxidases under various conditions. Appl. Microbiol. Biotechnol. [Epub ahead of print].
23. Martinez, A. T., J. Ruiz and M. J. Martinez. 1994. Influence of Mn concentration and N source on the production of ligninolytic enzymes in liquid cultures of Pleurotus species. P. 134. In Abstracts of the 5th International Mycological Congress, 1994. Vancouver. British Columbia, Canada.
24. Martinez, A. T., S. Camarero, F. Guillen, A. Gutierrez, C. Munoz, E. Varela, M. J. Martinez, J. M. Barrasa, K. Ruel and J. M. Pelayo. 1994. Progress in biopulping of non-woody materials: chemical, enzymatic and ultrastructural aspects of wheat straw delignification with ligninolytic fungi from the genus Pleurotus. FEMS Microbiol. Rev. 13: 265-274.
25. Michael, H G. and J. K. Glenn. 1988. Manganese peroxidase from Phanerochaete chrysosporium. Method Enzymol. 161B: 258-264.
26. Miller, G. L. 1959. Use of dinitrosalicylic acid reagent for determination of reducing sugar. Anal. Chem. 31 (3): 426-428.
27. Munoz, C, F. Guillen, A. T. Martinez and M. J. Martinez. 1997. Induction and characterization of laccase in the ligninolytic fungus Pleurotus eryngii. Curr. Microbiol. 34: 1-5.
28. Panbangred, W., A. Shinmyo, S. Kinoshita and H. Okada. 1983. Purification and properties of endoxylanase produced by Bacillulus pumilus. Agric. Biol. Chem. 47: 957-963.
29. Paszczynski, A., V. Huynh and R. Crawford. 1985. Enzymatic activities of an extracellular Mn-dependent peroxidase from Phanerochaete chrysosporium . FEMS Microbiol. Lett. 29: 37-41.
30. Pease, E. A., S. D. Aust and M. Tien. 1991. Heteroiogous expression of active manganese peroxidase from Phanerochaete chrysosporium using the Baculovirus expression system. Biochem. Biophys. Res. Commun. 179: 897-903.
31. Royer, J. C. and J. P. Nakas. 1990. Simple, sensitive zymogram technique for detection of xylanase activity in polyacrylamide gels. Appl. Environ. Microbiol. 56: 1516-1517.
32. Ruttimann-Johnson, C, D. Cullen and R. T. Lamar. 1994. Manganese peroxidases of the white rot fungus Phanerochaete sordida. Appl. Environ. Microbiol. 60(2): 599-605.
33. Sawyer, N. A., S. M. Chambers and J. W. Cairney. 2003. Utilisation of inorganic and organic nitrogen sources by Amanita species native to temperate eastern Australia. Mycol. Res. 107(Pt 4): 413-420.
34. Schoemaker, H. E. and M. S. A. Leisola. 1990. Degradation of lignin by Phanerochaete chrysosporium. J. Biotech. 13: 101-109.
35. Shuttleworth, K. L., L. Postie and J.-M. Bollag. 1986. Production of induced laccase by the fungus Rhizoctonia praticola. Can. J. Microbiol. 32: 867-870.
36. Singh, R. P., H. S. Garcha and P. K. Khanna. 1988. Laccase production by Pleurotus spp. Indian J. Microbiol. 28:38-41.
37. Tekere, M., R. Zvauya and J. S. Read. 2001. Ligninolytic enzyme production in selected sub-tropical white rot fungi under different culture conditions. J. Basic Microbiol. 41(2): 115-29.
38. Tien, M. and T. K. Kirk. 1983. Lignin degrading enzyme from the hymenomycete Phanerochaete chrysosporium burds. Science. 221: 661-663.
39. Tien, M. and T. K. Kirk. 1988. Lignin peroxidase of Phanerochaete chrysosporium. Methods Enzymol. 161:238-249.
40. Valmaseda, M., M. J. Martinez and A. T. Martinez. 1991. Kinetics of wheat straw solid-state fermentation with Trametes versicolor and Pleurotus ostreotus — lignin and polysaccharide alteration and production of related enzymatic activities. Appl. Microbiol. Biotechnol. 35: 817-823.
41. Vares, T., M. Kalsi and A. Hatakka. 1995. Lignin peroxidases, manganese peroxidases, and other ligninolytic enzymes produced by Phlebia radiata during solid-state fermentation of wheat straw. Appl. Environ. Microbiol. 61: 3515-3520.
42. Wolfenden, B. S. and R. L. Willson. 1982. Radical-cations as reference chromogens in kinetics studies of one-electron transfer reactions: pulse radiolysis studies of 2,2-azinobis (3-ethylbenzothiazoline-6-sulphonate). J. Chem. Soc. Perkin Trans. II. 1982.