Synthesis of gentiobiose by β-glucosidase and separation of the product

ZHANG Lin;WANG Lei;WU Guangxing;YONG Qiang;YU Shiyuan;College of Chemical Engineering,Nanjing Forestry University;

gentiobiose;;β-glucosidase;;cation exchange resin;;Bifidobacterium adolescentis

Gentiobiose was prepared by glucose catalyzed by β-glucosidase via transglycosylation. The effects of the source of the β-glucosidase,reaction temperature,pH,β-glucosidase dose,substrate concentration and reaction time on the gentiobiose were analyzed. The enzyme produced by Nanjing Forestry University was selected for the synthesis of gentiobiose. It was found that optimal conditions for synthesis were as follows: glucose at a concentration of 900 g/L was added with β-glucosidase at a dosage of 60 U/g glucose; the mixture was incubated at pH 5,temperature of 60℃w ith a shaking speed of 80 r/min; after 24 h,46. 9 g/L of gentiobiose was obtained. Anion exchange chromatography was used to quantitatively detected gentiobiose. Separation and purification of the gentiobiose product was completed by ion chromatography. Cation exchange resin was used in 2-step separation. The results showed that the gentiobiose was well separated from glucose after 2 times elution,getting a purity of 97. 0%. The prepared gentiobiose was used for the proliferation of Bifidobacterium adolescentis. Sugar source containing 74. 9 mmol/L of carbon was metabolized for 36 h,generating organic acids of 62. 1 mmol/L carbon and bacterium biomass of 7. 1 mmol/L carbon. The concentration of bacterium biomass increased by 3. 8 times,indicating that the gentiobiose prepared in this study was an effective inducer for B. adolescentis which was beneficial to human health.