Chitin, a linear polymer of β-1,4 linked N-acetylglucosamine is a major structural component of fungal cell wall, exoskeletons of arthropods, internal structures of cephalopods, protozoan cyst walls and helminth eggs. Chitinases are glycosyl hydrolases that cleaves the β-1,4-glycosidic bonds of chitin. It is present in a wide range of organisms, such as bacteria, viruses, higher plants and animals including mammals and play an important physiological and ecological role. The aim of our study was to characterize, optimize and compare the chitinase production in three Aspergillus species namely Aspergillus niger, Aspergillus oryzae and Aspergillus tamarii. The chitinase activity was characterised by altering pH, substrate concentration, incubation time and temperature and the enzyme production was optimized by varying different parameters like substrate, pH and static/shaking conditions. Maximum activity was obtained for a substrate concentration of 1% at pH 5 for 60 mins at 50 ֯C and a high level of chitinase production was observed in the culture medium with colloidal chitin as substrate at pH 7 in shaking conditions. The samples which showed maximum chitinase activity under optimized conditions were partially purified and protein band profile was observed on SDS-PAGE and chitinolytic activity was observed through zymogram analysis. Also, the comparative studies revealed that among the three Aspergillus species, Aspergillus niger showed better chitinolytic activity. Chitinases thus obtained could be used for various applications in areas like agriculture, biomedical research, marine waste management.
