Production and optimization of l-asparaginase by Streptomyces koyangensis SK4 isolated from Arctic sediment.

Abstract

Actinomycetes isolated from the Arctic sediment were evaluated for the production of the enzyme l-asparaginase, an enzyme used to treat acute lymphoblastic leukemia. The most potent strain Streptomyces koyangensis SK4 was selected for l-asparaginase enzyme production by submerged fermentation. The effect of various fermentation parameters on enzyme production was analyzed statistically using the Plackett-Burman design and response surface method. Effects of eight parameters including temperature, pH, incubation time, inoculum size, agitation speed, the concentration of starch, l-asparagine, and yeast extract were studied on l-asparaginase production by the Arctic isolate S. koyangensis SK4. Factors such as temperature, pH, incubation time, agitation speed, and l-asparagine concentration were found to be important factors influencing l-asparaginase production. Maximum enzyme activity of 136 IU/ml was obtained at 20°C on the seventh day of incubation in the asparagine dextrose broth maintained at pH 7.5, agitation speed 125 rpm, and l-asparagine concentration of 7.5 g/L. The statistical optimization method described in this study proved effective for increasing the l-asparaginase production by Arctic actinomycetes.