Enhanced biosynthesis of dextransucrase: A multivariate approach to produce a glucosyltransferase for biocatalysis of sucrose into dextran.

The current study reported the statistically designed experimental method to enhance the biocatalytic efficacy of dextransucrase from Weissella confusa. Various environmental and nutritional parameters were optimized using multiple responses under submerged fermentation environment. Statistical models were constructed to screen the influence of nine factors on the biocatalysis of dextransucrase. Among them, fermentation time, pH, sucrose and peptone exhibited significant probability (P < 0.05) and are considered as substantial constituents in accordance with Plackett-Burman design. Central composite design was further implemented to optimize the levels of selected variables for maximum enzyme yield. The predicted optimum conditions were pH of 7.5 under fermentation time of 8 h with 30.0 g l sucrose and 1.0 g l peptone. The overall enzyme yield increased from 11.4 DSU ml to 52.75 DSU ml with 4.62-fold upsurge after the implementation of the statistical models. Furthermore, SEM analysis showed the biocatalytic conversion of sucrose into highly porous dextran when utilizing dextransucrase. The biopolymer produced under the current optimized model could be utilized as an emulsifying, gelling, stabilizing and thickening agent in food industry.