Effect of UV rays and other chemicals on cellulase production of Aspergillus niger in submerged fermentation using rice husk as substrate

Abstract

Cellulases are employed in variety of sectors. Cellulases produced by microbes have already proven effective in different sectors. The efficiency of microbial cellulase production can be improved by treating microbes with mutagens. To investigate the impact of mutagens on cellulase production, Aspergillus niger spores were exposed to UV radiation, ethidium bromide, and nitrous acid and cellulase activity was measured after each treatment. Wild strain Aspergillus niger has the capacity to produce 0.18 IU/ml/min CMC-ase and 0.27 IU/ml/min FP-ase activities. Short-wave UV light (254 nm) exposure for 30 minutes resulted in a 39% increase in CMC-ase and 33% increase in FP-ase activities, while long-wave UV light (366 nm) exposure resulted in a 33% increase in both CMC-ase and FP-ase activities, compared to the wild strain. CMC-ase and FP-ase activities after 0.25 mg ml^-1 ethidium bromide treatment increased about 22% and 16% respectively than the wild strain whereas 0.25 M nitrous acid treatment gave 101% increase in CMC-ase activity and 48% increase in FP-ase activities. Nitrous acid proved more effective in increasing cellulase activity to the greater extent as compared to UV exposure and ethidium bromide treatment. This study suggest that mutagenesis of fungal strain could provides a new choice for processing of bioresources in the future.