Mycothermus thermophilus (Syn. Scytalidium thermophilum/Humicola insolens), a thermophilic fungus, is being reported to produce appreciable titers of cellulases and hemicellulases during shake flask culturing on cellulose/wheat-bran/rice straw based production medium. The sequential and differential expression profile of endoglucanases, β-glucosidases, cellobiohydrolases and xylanases using zymography was studied. Mass spectrometry analysis of secretome (Q-TOF LC/MS) revealed a total of 240 proteins with 92 CAZymes of which 62 glycosyl hydrolases belonging to 30 different families were present. Cellobiohydrolase I (17.42%), β glucosidase (8.69%), endoglucanase (6.2%), xylanase (4.16%) and AA9 (3.95%) were the major proteins in the secretome. In addition, carbohydrate esterases, polysaccharide lyases, auxiliary activity and a variety of carbohydrate binding modules (CBM) were identified using genomic database of the culture indicating to an elaborate genetic potential of this strain for hydrolysis of lignocellulosics. The cellulases from the strain hydrolyzed alkali treated rice straw and bagasse into fermentable sugars efficiently.
Keywords: Glycosyl hydrolases; Hydrolysis; Mycothermus thermophilus; Q-TOF LC/MS based secretome analysis; Thermophilic fungus.
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