Nitrogen sources: To select the best nitrogen source, the chitin medium was supplemented with different inorganic (0.5 g L_,) and organic introgen sources (I g L-'). Among the various nitrogen sources in the basal medium, ammonium sulfate and peptone were the most effective additives resulting in the increase of the enzyme production (Fig. 2). However, in the case of meat extract, soybean powder, gelatin, ammonium nitrate, ammonium biphosphate and ammonium acetate, chitinase production was repressed from 15 to 60%. Ammonium sulfate and peptone gave nearly 15% increase m chitinase productivity. Ammonium sulfate was chosen as the simplest and cheapest nitrogen source for preparation of next media.