Cellulase and Xylanase from Phanerochaete chrysosporium ATCC24725: Production, Regulation of Synthesis, and Properties.

Abstract

In this study, nine wood-rotting basidiomycete species were screened for cellulase and xylanase production in submerged fermentation of crystalline cellulose. Phanerochaete chrysosporium ATCC 24725 was the best producer of CMCase and xylanase, with enzymatic activity of 71.7 U/mL and 75.9 U/mL, respectively. The total cellulase, endoglucanase, and xylanase activities of P. chrysosporium ATCC24725 in the presence of lignocellulosic substrates were 3-7 times lower than the activity of these enzymes in the medium with crystalline cellulose. However, the endoglucanase activity of Trametes ochracea BCC76 in the medium containing tangerine pomace was the same as in the medium containing Avicel, whereas the xylanase activity was 3 times higher. Cellulase and xylanase synthesis in P. chrysosporium ATCC24725 occurs through induction mechanisms. Cellulose and cellulose-containing materials are the most suitable substrates for cellulase and xylanase production in P. chrysosporium ATCC24725, whereas CMC and xylan proved to be poor substrates for stimulating the secretion of these enzymes. In P. chrysosporium ATCC24725, cellulase and xylanase synthesis do not occur in the presence of easily metabolizable carbon sources due to catabolite repression, even if cellulose is present in the nutrient medium. Induction of enzyme synthesis resumes only after the easily metabolizable carbon source is depleted. The enzyme preparation isolated after culturing the fungus in a fermenter was partially purified and characterized. A crude cellulase preparation from P. chrysosporium ATCC24725 showed similar efficiency as Accellerase 1500 in the hydrolysis of alkali-pretreated wheat straw. The obtained results highlight the potential of P. chrysosporium ATCC 24725 as a reliable fungal cellulase producer for biorefinery applications.