Use of mutation strategies applied to Aspergillus terreus ATCC 52430 to obtain mutants with improved cellulase productivity

Abstract

Mutation studies were carried out on Aspergillus terreus ATCC 52430 to increase cellulase production. Optimal treatment conditions for increasing cellulase activity by UV mutagenesis were observed by exposure of spores to a UV germicidal lamp, wavelength 250 nm at a distance of 30 cm for 1 min. Nitrosoguanidine mutagenesis was optimal with respect to development of high cellulase mutants when spores were exposed to 500 ug/ml nitrosoguanidine for 1 h. Mutants were isolated on agar containing Walseth cellulose and the catabolite repressor, glycerol. Successive UV and nitrosoguanidine treatments resulted in isolation of strain UNG1-40 having 3.5, 4.6 and 3.3-fold increases in filter paper, beta-glucosidase and carboxymethyl cellulase activity, respectively, compared to A. terreus ATCC 52430.