Optimization of Process Parameters for Chitinase Production by a Marine Isolate of Serratia marcescens

Abstract

Chitinases play an important role in the decomposition of chitin and results in the utilization of chitin as a renewable resource. A total of 18 chitinolytic bacteria were isolated from the sand sample. Following primary and secondary screening in colloidal chitin medium, strain CBC-5 demonstrated the highest chitinolytic activity and was selected for further study. It was later identified as Serratia marcescens. Addition of easily metabolized sugars had inhibitory effect on the enzyme production and the highest yield was obtained with colloidal chitin as the sole source of carbon and yeast extract (1% w/w) as nitrogen source. 10.3 % increase in chitinase yield was observed when Triton X-100 was added to the medium. The optimum pH, temperature, and incubation period for chitinase production by the isolate was found to be 7.0, 30°C and 72 h respectively. Sodium dodecyl sulphate polyacrylamide gel electrophoresis revealed the apparent molecular weight of the enzyme to be 42 kDa. The results obtained in the present study showed that isolated bacterium is a potent producer of chitinase and the enzyme can be exploited for the biodegradation of chitinous wastes and may find applications as biocontrol agents against fungi and insects.