Cyclodextrin glucanotransferase (CGTase) is an important enzyme with multiple functions in starch utilization. In the present study, a fermentation process for the production of CGTase from Escherichia coli harboring the recombinant plasmid pET28b(+)-CGTase was investigated and optimized. The optimal fermentation and expression conditions were 10.0 g/L glycerol, 20.0 g/L tryptone, and 10.0 g/L yeast extract with an initial pH of 7.0, an IPTG concentration of 0.1 mM and an induction temperature of 28 °C for 10 h. The resulting CGTase activity reached up to 36.4 U/L and was 2.1-fold higher than before optimization. Under these optimal fermentation conditions, the up-scaled fermentation was carried out in a 500-L fermentor, and a CGTase activity of 45.2 U/L was achieved. This study provides a foundation for the industrial production of CGTase.
Keywords: CGTase; Fermentation; Optimization; Production; Purification.