Abstract: Chitooligosaccharides exhibit a broad range of potential applications in the fields of biomedicine, pharmaceuticals, food, cosmetics and agriculture. In the present study, based on the results from single factor tests, response surface methodology (RSM) combined with central composite design was used to optimize cultivation conditions of Bacillus thuringiensis ZJOU-010 for producing chitosanase. The optimal conditions were achieved to be shrimp shell powder (SSP) concentration of 44.96 g/L, (NH4)2SO4 concentration of 1.48 g/L, and pH of 6.78. Under the optimal conditions, the chitosanase activity from Bacillus thuringiensis ZJOU-010 was 4.25 U/mL. The obtained value of chitosanase activity was in good agreement with the predicted value (4.16 U/mL). Meanwhile, 18.47% improvement on chitosanase activity after the optimal cultivation was achieved, when compared with the chitosanase activity of 3.59 U/mL before optimization. These results indicated that oligosaccharides could be produced using shrimp processing by-products as the carbon and nitrogen sources.

Key words: chitooligosaccharides, shrimp shell powder, chitosanase, optimization, response surface methodology