USE OF PROTEOLYTIC-ENZYMES TO FACILITATE THE RECOVERY OF CHITIN FROM SHRIMP WASTES

Two proteolytic enzymes, chymotrypsin and papain, were used to hydrolyze proteins associated with demineralized shrimp waste to recover chitin. The conditions used were optimized using response surface methodology (RSM). The factors studied were temperature (3 levels), pH (3 levels) and enzyme to waste ratio (E/W ratio)(5 levels). Of these, pH was the most important factor in the models obtained. Optimum conditions for deproteinization by chymotrypsin were determined to be around 40 degrees C, pH 8.0 and E/W ratio of 7:1000 (w:w). With papain, a temperature of around 38 degrees C, pH of 8.7 and E/W ratio of 10:1000 (w:w) gave the optimum response. At these conditions, the yield of protein was maximum, and ranged from 22-48% depending on the starting material. The residual protein levels in the waste after deproteinization with the enzymes were very low, i.e., 1.3 and 2.8% for chymotrypsin and papain-treated samples, respectively.