High-level extracellular production of α-cyclodextrin glycosyltransferase with recombinant Escherichia coli BL21 (DE3).

High-level production of α-cyclodextrin glycosyltransferase (CGTase) is one of the key factors in α-cyclodextrin (CD) preparation. In the present study, a fed-batch fermentation strategy for high-cell-density cultivation of Escherichia coli and the extracellular production of recombinant α-CGTase from Paenibacillus macerans JFB05-01 was established. A combined feeding strategy based on both specific growth rate before induction and the amount of glycerol residues after induction was used to control cell growth, acetate production, and glycerol consumption. When induced by lactose, a feeding solution with complex nitrogen was found beneficial for α-CGTase production. In addition, different induction temperatures and induction points were investigated, and the results indicated that these factors played an important role in α-CGTase production. When induced at 25 °C and at a dry cell weight of 30 g L(-1), the extracellular activity of α-CGTase could reach 275.3 U mL(-1).