Purification and characterization of β-glucosidases and β-xylosidase of A. niger NCIM 1207

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Enzymatic decrystallization of lignocellulosic biomass is critical and currently poorly understood. Conversion of such biomass to commodity chemicals such as biofuels is not cost effective due to several challenges. The major challenge is the suitable cellulase complex capable of degrading untreated or treated lignocellulosic biomass completely to give monomeric fermentable sugars. Many fungi produce cellulase complex but not in proper proportion. Trichoderma produces higher amounts of endoglucanases, which is deficient in b-glucosidase, and Aspergillus produces higher b-glucosidases but less endoglucanases. The fungus capable of producing all enzymes in proper proportion and in higher amounts would probably make cellulase production cost effective. A. niger isolated in our laboratory produced remarkably high levels of both b-glucosidase and b-xylosidase when grown on xylan-containing media. The supplementation of commercial cellulases with such enzyme preparations may help in reducing the enzyme doses needed to achieve complete hydrolysis of cellulose. Hence, we feel that this fungus is a potential candidate to produce both b-glucosidase and b-xylosidase in high amounts, which can be used to supplement commercial cellulase. preparations.

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