知识与财富的链接
发酵初期在米根霉菌发酵培养基中添加L-乳酸可以调控发酵产物乳酸的光学纯度。随着L-乳酸添加量的增加,所产L-乳酸的光学纯度随之增加,当L-乳酸的添加量≥1.5g/L时,D-乳酸不再产生。同时,L-乳酸的产量、生物量、糖转化率也随之降低。该调控方法对乳酸菌调控产L-乳酸光学纯度影响不大,对大肠杆菌发酵调控产D-乳酸光学纯度没有效果。
The effect of cultivation conditions on the optical purity of L(+)-lactic acid produced by Rhizopus oryzae HZS6 was investigated.The isomeric composition of lactic acid was influenced by the supplementation of L(+)-lactic acid to fermentation medium.L(+)-isomer increased with the dosage, no D(-)-lactic acid was observed when the concentration of supplemented L(+)-lactic acid in matrix was ≥ 1.5 g/L.However, the L(+)-lactic acid yield, biomass and glucose conversion rate decreased with the dosage.With the same method, the supplementation of L(+)-lactic to substrate had no influence on isomeric composition of lactic acid by Lactobacillus and Escherichia coli.
