Abstract:

Twenty chitosanase-producing bacterium strains were isolated from Lianyungang seaside. Among them strain S-1 had the highest chitosanase-producing capacity and was identified as Bacillus sp. based on its morphological, physiological and biochemical properties as well as 16S rDNA sequence analysis. Single-factor method and orthogonal array design were adopted to optimize the medium composition and fermentation parameters to maximize chitosanase activity, respectively. The optimal medium for enzyme production consisted of 15 g/L shrimp- and crab-shell powder, 10 g/L NH4NO3, 3 g/L yeast extract, 1.4 g/L K2HPO4·3H2O, 5 g/L NaCl,1.4 g/L MgSO4·7H2O and 1 g/L glucose at an initial pH of 6.0 and the optimal filling volume was 100 ml in 500 ml flask. After cultivation at 32 ℃ for 72 h, the maximal chitosanase activity was observed to be 6.4 U/ml. This strain has promising potential in the industrial production of chitosanase.

Key words: chitosanase, screening, identification, fermentation optimization, Bacillus