Optimization of medium composition for the production of elastase by Bacilus sp. EL31410 with reponse surface methodology

摘要

A newly isolated strain EL31410, which produced elastase (E.C.3.4.4.7) with a high elastolytic activity was identified as Bacillus sp. The optimal conditions for the enzymtic reaction occurred at pH 7.4 and 37deg C. Glucose and Casein are the best carbon and nitrogen sources for enzyme production. Adition of corn steep flour can affect the bacterium growth and elastase productin. A fractional factorial design was applied to study the main factors that affect the enzyme production and the central composite experimental design and response surface methodology were adopted to derive a statistical model for the effect of casein and corn steep flour on elastase proudction. These experimental results showed that the corn steep flour had a postiive effect and the high asein had a negative effect on enzyme production. An initial concentrtion of 1.15% (w/v) casein and 0.61% (w/v) corn steep flour were found to be tbest for the elastase productionin batch culture. In addition, the time course of elastase production in the optimized medium compositin was also described.