Efficient production of inulin and oligosaccharides using thermostable inulosucrase from Lactobacillus jensenii

Fructan, inulin and levan, have been applied in many industrial fields because of their versatile properties and functions. Recently, microbial fructan has attracted much attention. In this study, a novel inulosucrase from Lactobacillus jensenii JV-V16 was constructed by truncating partial sequence. The truncated inulosucrase was overexpressed, purified and identified. The optimized pH and temperature for transfructosylation were pH 6.0 and 45 °C, respectively. The inulosucrase showed high thermostability and the half-life at 60 °C was 14.5 h. It also exhibited high transfructosylation capability, resulting in a high ratio of transfructosylation activity to hydrolysis activity. After optimizing the conditions of inulin production, 278.4 g/L inulin was obtained from 600 g/L sucrose with an approximately 46% conversion rate from sucrose to inulin. Additionally, acceptor reaction was attempted to explore the transfructosylation capability of the enzyme and some novel saccharides were detected, indicating the potential application in the synthesis of prebiotics.