Optimization of medium composition for the production of elastase by Bacillus sp. EL31410 with response surface methodology

A newly isolated strain EL31410, which produced elastase (E.C3.4.4.7) with a high elastolytic activity was identified as Bacillus sp. The optimal conditions for the enzymatic reaction occurred at pH 7.4 and 37°C. Glucose and Casein are the best carbon and nitrogen sources for enzyme production. Addition of corn steep flour can affect the bacterium growth and elastase production. 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 production. These experimental results showed that the corn steep flour had a positive effect and the high casein had a negative effect on enzyme production. An initial concentration of 1.15%(w/v) casein and 0.61%(w/v) corn steep flour were found to be best for the elastase production in batch culture. In addition, the time course of elastase production in the optimized medium composition was also described.