Biochemical Characteristics of Immobilized Chitinase from Alternaria infectoria

This research aimed to purify and immobilize chitinase from Alternaria infectoria and to study its biochemical characteristics for biotechnological applications. Chitinase (EC. 3. 2. 1. 14) was purified by ammonium sulphate precipitation, DEAE-cellulose and then Sephadex G-200 with specific activity of 51.9 U mg-1 protein. The pH values were 7, 8 and 9 for the free, silica gel –immobilized and entrapped enzyme. The optimal temperatures were 40, 50 and 60°C for the three forms of chitinase, respectively. The activation energy values were 43.2, 30.8 and 11.6 KJ mol-1. Ca2+ was activator whereas Hg2+, Cd2+ and Ni2+ were inhibitors. However, K+ and Mg2+ showed no remarkable effect. The immobilized chitinase retained appreciable activity after 8 cycles particularly entrapped enzyme. The entrapped chitinase expressed higher stability against desorptivity by SDS than silica gel-immobilized enzyme. Thus, the results reveal that immobilized chitinase expressed higher thermostability compared to the free enzyme and this was important for industrial applications.