Enhancing Stability and Purity of Crude Chitinase of Achatina fulica by Crystallization

A crystallization method was developed to enhance the purity and stability of hydrolase mixtures from the digestive gland of the snail Achatina fulica, as demonstrated by chitinase activity. Crude chitinase was concentrated by freeze drying and then crystallized at 10 °C. Crystal formation was observed under the microscope. The best concentration for crystallization was obtained with 1.5-fold concentrated crude chitinase. Crystallization enhanced the chitinase specific activity from 0.87 U mg-1 to 0.95 U mg-1. The loss of chitinase activity from liquid and crystals of crude chitinase on four days storage at 10 °C was 83.0% and 17.7%, respectively. It was concluded that the crude chitinase crystals showed a significant increase in stability and purity.