The process for production of trehalose using trehalose synthase (TreS) to convert maltose into trehalose in one step is highly desirable in the industry. Nonetheless, the studies on industrial-scale production of trehalose by recombinant TreS in Escherichia coli are still scarce. In this study, a TreS from Pseudomonas putida ATCC47054 was expressed in E. coli BL21(DE3) via plasmids pET15b and pET22b. pET15b-treS showed better plasmid stability and TreS expression, which revealed that the highest activity, 39866±1420U/(g dry cell weight) at the final lactose concentration of 4g/L for 7h at 27°C in a 5-L fermentor at pH 8.0. The use of 30% (w/v) high-maltose syrup as a substrate can extend the temperature tolerance of TreS to 60°C. More than 64% of maltose can be converted into trehalose by adding 200U of TreS per gram of maltose at 50°C for 24h. The total sugar content of the trehalose syrup reached 95.0%±1.0% (w/w) after separation. The recovery rate of trehalose dehydrate reached 57.0%±2.0% after slow cooling, and the purity was 99.0±0.2%. Our study revealed a safe and reliable process of trehalose production by recombinant TreS.
Keywords: Production; Purification; Trehalose; Trehalose synthase.
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