产共轭亚油酸瑞士乳杆菌L7固定化条件的研究

摘要

Immobilized Lactobacillus helveticus L7 was used for biosynthesizing c9,t11-CLA from linoleic acid.The immobilization conditions were optimized by response surface methodology.The optimal conditions for the preparation of immobilized cells required 1.78 g/100 mL sodium alginate,3.13 g/100 mL calcium chloride and 30 min immobilization time.The fermentation of immobilized cells under the optimal conditions could result in the highest accumulation of c9,t11-CLA up to 561 μg/mL.Meanwhile,the immobilized strain displayed good transformation properties.No obvious change in the activity of the immobilized strain was observed after reuse for five times,and the yield of c9,t11-CLA remained up to 549 μg/mL.Examined by scanning electron microscope(ESEM),the internal structure and surface of immobilized bead were observed,and were suitable for the mass transfer.Therefore,sodium alginate-immobilized cells had a good performance in improving the recycling rate of cells,reducing the production costs of c9,t11-CLA,and improving economic efficiency of enterprises.%对瑞士乳杆菌（Lactobacillus helveticus）L7发酵生产c9,t11-CLA的固定化条件进行研究。应用响应面法对细菌固定化的条件进行优化,得到的优化条件为：海藻酸钠质量浓度1.78g/100mL、氯化钙质量浓度3.13g/100mL、固定化时间60.30min,利用在此条件下制备所得的固定化胶珠发酵,c9,t11-CLA的产量达到561μg/mL。固定化细胞重复利用5次后活力没有明显变化,c9,t11-CLA产量保持在549μg/mL。电镜观察发现,固定化胶珠表面及内部为错综复杂的网状通道结构,能够很好的满足物质的传递。结果表明菌体细胞经海藻酸钠固定,可以有效提高菌体的重复利用率,从而降低c9,t11-CLA的生产成本。