Enzymatic Synthesis Of Alkyl Glycosides

As a biodegradable,environmentally friendly nonionic surfactant,alkyl glycosides have been widely used in the detergent industry.High-purity alkyl glycosides are of great value in many high-end fields such as household chemicals,pharmaceuticals and biological agents.Alkyl glycosides were synthesized from long chain alcohol and glucose using the whole cell of engineered bacterial strain expressing ?-glucosidase as catalyst.The reaction conditions and influencing factors and separation and purification methods of whole-cell catalytic synthesis of n-octyl glucoside and n-hexyl glucoside were studied.The main research contents and results are as follows:The feasibility of expression of ?-glucosidase in genetically engineered bacteria induced by lactose instead of IPTG(Isopropyl-beta-D-thiogalactoside)was studied.The composition and culture method of lactose-induced fermentation medium were optimized by shake flask experiments.The results showed that the optimal condition was 3% in seed solution,the lactose concentration was 2%,the lactose induction time was 2 h,the induction temperature was 34?,pH=7,and the induction time was 4 d,the enzyme activity reached 157.9 U/mL,which was about 5.42 times that induced by IPTG.n-Octyl glucoside and n-Hexyl glucoside was synthesized from n-octanol /n-hexanol and glucose using the whole cell of engineered bacterial strain expressing ?-glucosidase as catalyst.The reaction conditions were as follow: the quality ratio of glucose to n-octanol of 1:5(g/g),the catalyst amount of 2.0%,the reaction temperature of 52 ?,the reaction time of36 h,pH=6,vibration speed of 180 r/min,the glucose conversion rate could reach to 62.12%.The product is identified by infrared spectroscopy,Raman spectroscopy and nuclear magnetic resonance spectroscopy,and the synthesized product was determined to be n-octyl glucoside.The purity of n-octyl glucoside was determined by pre-column derivatization-gas chromatography.The reaction conditions were as follow: the quality ratio of glucose to n-hexanol of 1:5(g/g),the catalyst amount of 1.5%,the reaction temperature of 52 ?,the reaction time of36 h,pH=5,vibration speed of 180 r/min,the glucose conversion rate could reach to 73.27%.The product is identified by infrared spectroscopy and the synthesized product was determined to be n-hexyl glucoside.The purity of n-hexyl glucoside was determined by pre-column derivatization-gas chromatography.