OPTIMIZATION OF CONDITIONS FOR LIPOXYGENASE PRODUCTION FROM RECOMBINANT Bacillus subtilis BY RESPONSE SURFACE METHODOLOGY

Influences of seven related factors on productivity of lipoxygenase by recombinant Bacillus subtilis were studied by the method of Plackett-Burman design.As a result,the lactose,fermentation time and temperature were found to be the most important factors.Meanwhile,a three-level four-factor central composite design was applied to optimize the levels of the chosen variables and their interaction.By analysis of the 3-D plots and corresponding plots,while the lactose concentration was 16.9g/L,fermentation time 88.49h,temperature 29.71℃ and culture volume was 61.31ml,enzyme activity reached the maximum value 164.90U/ml.Verification experiments under the above conditions gave the enzyme activity of 167.32U/ml,which showed high homology with predictive value.The yield of lipoxygenase was 2.37 times higher than before in the optimized fermentation conditions.