用固定化氧化葡萄糖酸菌转化6-(N-羟乙基)胺基-6-脱氧-L-山梨呋喃糖

Biotransformation of 6-(N-hydroxyethyl)amino-6-deoxy-L-sorbofuranose by immobilized Gluconobacter oxydans

目的探索用固定化氧化葡萄糖酸菌转化6-(N-羟乙基)胺基-6-脱氧-L-山梨呋喃糖的最优条件。方法以海藻酸钠为载体把氧化葡萄糖酸菌固定化,考察固定化细胞在不同转化条件时对底物的转化率。结果通过条件优化,确定固定化细胞转化时间为24 h,底物质量浓度为10 g.L-1,采用的海藻酸钠质量浓度为40g.L-1,菌体包埋量为每g凝胶包埋3.1 g菌体,最适pH为7.0,最适温度为28℃,摇床转速要求高于100r.min-1;用60mmol.L-1的MnCl2替代原转化液中20mmol.L-1的MgSO4;固定化细胞与原游离细胞工艺相比,24h内底物转化率由原来的47%上升到93%,连续转化10次后,转化率仍为38%。结论用固定化氧化葡萄糖酸菌转化6-(N-羟乙基)胺基-6-脱氧-L-山梨呋喃糖,转化率提高46%并能连续转化约10次。

Objective To establish the optimal conditions for biotransformation of 6-（N-hydroxyethyl） amino-6-deoxy-L-sorbofuranose by immobilized Gluconobacter oxydans. Methods Gluconobacter oxydans was immobilized with sodium alginate, and the conversion rate towards the substrate were determined under different conditions. Results The optimal conditions were as follows：the conversion time was 24 h;the substrate concentration in the reaction solution was 10 g · L^-1; the concentration of sodium alginate was 40 g · L^-1 and the cell content in the immobilized beads was 3.1 g wet weight/g dry gel;the optimum pH and optimum temperature of the immobilized cells were pH 7.0 and 28 ℃, and the rotation speed of the rocking bed was above 100 r · min^- 1 ; 20 mmol· L^- 1 MgSO4 was substituted with 60 mmol·L^- 1 MnCl2 in the reaction solution. The conversion rate of 6-（ N-hydroxyethyl）arnino-6-deoxy-L-sorbofuranose by immobilized cell had increased to 93 96 and 38 96 of the conversion rate was obtained after 10 batches in continuous cycles. Conclusions The conversion rate of 6-（N-hydroxyethyl） amino-6-deoxy-L-sorbofuranose by immobilized Gluconobacter oxydans had increased 46 96 compared with free cells, the continuous cycles can remained about 10 batches.