Fig. 3

Optimization of recombinant biocatalyst preparation for rutin biotransformation. A Fed-batch fermentation for the production of recombinant biocatalysts. The recombinant biocatalysts were tested for the enzyme activities of rhamnosidase and glucosidase, and the quercetin yields were quantified by HPLC. B Rutin biotransformation using different amounts of the recombinant biocatalysts. Rutin was supplied to the biotransformation system at 30 g/L and 40 g/L, with varied amounts of wet-weight recombinant biocatalyst. The substrate residues and product quercetin were analyzed by HPLC to evaluate the performance of the recombinant biocatalysts. C Performance of the recombinant biocatalysts prepared from optimized fed-batch fermentation. Fed-batch fermentation was conducted to boost biomass formation and enzyme production. The enzyme activities, substrate consumption, and product formation were measured after 25 and 37 h. D HPLC analysis of the performance of recombinant biocatalysts in rutin biotransformation prepared using various methods. a The recombinant biocatalysts produced by flask fermentation using SDM1 with an initial rutin concentration of 10 g/L; b the recombinant biocatalysts produced by scale-up production using SDM2 with an initial rutin concentration of 40 g/L; and c the recombinant biocatalysts produced by optimized fed-batch fermentation using SDM3 with an initial rutin concentration of 40 g/L. Error bars represent standard deviations