The brown-rot basidiomycete Fomitopsis palustris has the endo-glucanases capable of degrading microcrystalline cellulose.
Two endoglucanases with processive cellulase activities, produced from Fomitopsis palustris grown on 2% microcrystalline cellulose (Avicel), were purified to homogeneity by anion-exchange and gel filtration column chromatography systems. SDS-PAGE analysis indicated that the molecular masses of the purified enzymes were 47 kDa and 35 kDa, respectively. The amino acid sequence analysis of the 47-kDa protein (EG47) showed a sequence similarity with fungal glycoside hydrolase family 5 endoglucanase from the white-rot fungus Phanerochaete chrysosporium. N-terminal and internal amino acid sequences of the 35-kDa protein (EG35), however, had no homology with any other glycosylhydrolases, although the enzyme had high specific activity against carboxymethyl cellulose, which is a typical substrate for endoglucanases. The initial rate of Avicel hydrolysis by EG35 was relatively fast for 48 h, and the amount of soluble reducing sugar released after 96 h was 100 microg/ml. Although EG47 also hydrolyzed Avicel, the hydrolysis rate was lower than that of EG35. Thin layer chromatography analysis of the hydrolysis products released from Avicel indicated that the main product was cellobiose, suggesting that the brown-rot fungus possesses processive EGs capable of degrading crystalline cellulose.
Yoon
Jeong-Jun
JJ
Department ofBioscience and Biotechnology, Konkuk University, Seoul 143-701, Korea. jjyoon@konkuk.ac.kr
Cha
Chang-Jun
CJ
Kim
Yeong-Suk
YS
Son
Dong-Won
DW
Kim
Young-Kyoon
YK
D001487:Basidiomycota / Q000201:enzymology*; D002266:Carboxymethylcellulose Sodium / Q000378:metabolism; D002475:Cellobiose / Q000378:metabolism; D002480:Cellulase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002482:Cellulose; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D020075:Phanerochaete / Q000235:genetics; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid
D002475:Cellobiose; D002482:Cellulose; D002480:Cellulase; D002266:Carboxymethylcellulose Sodium; C109691:microcrystalline cellulose