Rational approach for mutant selection of Talaromyces verruculosus IIPC 324 secreting biofuel cellulases-Assessing saccharification potential

The present study describes a rational approach for mutant selection of Talaromyces verruculosus IIPC 324, where its 6-8 h old germinated spores were exposed to UV irradiation at 254 nm for 1 h. In total 10 mutants were obtained with a kill rate of 99.99%. Based on cellulases assays, none of the mutants showed simultaneous enhancement with respect to all the three components namely cellobiohydrolase, endoglucanase and cellobiase. Assessing saccharification potential with sugarcane bagasse as the feedstock resulted in the selection of mutant UV-8. The 10th generation of this mutant registered endoglucanase activity and cellobiase activity of 381.91 +/- 5.4 and 50.73 +/- 0.5 IU/g, respectively, on 4th day of fermentation. Its enzyme cocktail released 12.97 +/- 0.65 g L-1 of reducing sugar from dilute sulfuric acid pretreated sugarcane bagasse after 72 hat 60 degrees C. Thus random mutagenesis by UV irradiation resulted in obtaining a stable mutant, whose endoglucanase productivity and hydrolytic potential, both improved by similar to 1.48 and similar to 1.4 fold, respectively, when compared to its parent strain.