催化蔗糖-6-乙酸酯合成的微生物筛选和培养条件优化

Screening of strains for sucrose-6-acetate synthesis and optimization of culture conditions

三氯蔗糖是目前最优秀的功能性甜味剂之一,其合成的关键步骤是蔗糖-6-乙酸酯的合成。从土壤中分离到一株能够在有机溶剂中催化合成蔗糖-6-乙酸酯的杆状细菌,命名为WZS01。对该菌株的培养基和培养条件进行了初步优化,在2.5%葡萄糖,1%蛋白胨,0.1%酵母粉培养基中,以聚氨酯泡沫作为菌体固定化基质,30℃培养18 h。将吸附有菌体的聚氨酯泡沫干燥后作为催化剂,在2%底物浓度下,在二甲基甲酰胺/叔丁醇反应介质中催化18 h,蔗糖-6-乙酸酯的摩尔产率达到83.3%,并通过红外和核磁确认了产物结构。

Sucralose is one of the best functional sweeteners currently. The key step of sucralose synthesis is preparation of sucrose-6-acetate. An organic solvent tolerant and rod-shaped bacterium WZS01, which can synthesize sucrose-6-aeetate with sucrose as substrate was isolated. The media and culture conditions were optimized. The cells were immobilized on polyurethane foam after cultured 18 h in sterile medium containing glucose 2.5%, peptone 1%, and yeast extract 0.1%. The dried immobilized cells were used for sucrose-6-aeetate synthesis in dimethyl formamide/tert butyl alcohol and the yield of suerose-6-aeetate reached 83.3% with 2% sucrose after 18 h reaction. The structure of sucrose-6-acetate was confirmed by IR and NMR.