Optimization of leucrose production by dextransucrase from Streptococcus mutans and its application as an adipogenesis regulator

•Leucrose was produced by dextransucrase isomerization of on sucrose.•The production yield of leucrose was about 24.5 ± 3.5% by this enzymatic process.•Leucrose inhibited the adipogenesis by regulating adipogenic gene expression.•Leucrose has a potential to serve as a functional sweetener. Leucrose is a sucrose isomer which has an α-1,5-linkage, and slowly hydrolyzed to glucose and fructose by small intestinal α-glucosidases. Leucrose can be produced by an isomerization reaction of dextransucrase on a sucrose substrate. In this study, the recombinant dextransucrase from Streptococcus mutans (SmDS) was applied to optimize the reaction conditions for leucrose production. With a substrate mixture of 0.5 M sucrose + 1.0 M fructose, the greatest yield (ca. 24.5%) of leucrose was obtained by SmDS treatment at 30°C for 120h. When preadipocyte 3T3-L1 cells were treated with leucrose, this disaccharide inhibited intracellular lipid accumulation in a dose-dependent manner and significantly suppressed mRNA levels of major adipogenic genes, including CCAT/enhancer-binding protein α (C/EBPα), peroxisome proliferator-activated receptor-γ (PPARγ), fatty acid synthase (FAS), and sterol regulatory element-binding protein-1C (SREBP-1C). Phosphorylation of PI3 kinase/Akt/mTOR was also reduced with leucrose treatment. These results suggest that leucrose has a potential in regulating adipogenesis.