Abstract: An engineered strain E. coli PUCRF producing β-cyclodextrin glycosyltransferase (β-CGTase) has constructed in our lab. In this study, response surface analysis was used to optimize the culture medium composition for the production of β-CGTase by the strain. On the basis of one-factor-at-a-time experiments, a 4-factor, 3-level central composite design was performed. The optimum culture medium composition (g/100 mL) was determined as follows: corn starch 0.962, corn syrup 0.097, MgSO4 ·7H2O 0.153 and K2HPO4 ·3H2O 1.235. The correspondingβ-CGTase yield was 3610 U/mL, 1.34 times higher than before the optimization (2690 U/mL).

Key words: response surface analysis, β-cyclodextrain glycolstransferase, fermentation, medium