2,3-丁二醇生产菌株生产能力的比较和培养基优化

对5株克雷伯氏肺炎杆菌 (包括两株乳酸途径被敲除的工程菌株) 发酵生产2,3-丁二醇能力进行了比较，其中K. pneumonia HR521 LDH (乳酸合成途径中ldhA基因被敲除) 具有最佳的发酵性能。通过正交试验优化了其发酵培养基的主要组分，优化后的培养基组成为：葡萄糖 90 g/L，(NH4)2HPO4 3 g/L，玉米浆 (CLSP) 6 g/L，乙酸钠 5 g/L，KCl 0.4 g/L，MgSO4 0.1 g/L，FeSO4·7H2O 0.02 g/L，MnSO4 0.01 g/L。在优化后的发酵培养基中进行摇瓶发酵，24 h发酵乙偶姻和2,3-丁二醇的终浓度为37.46 g/L，比未优化前增加了10 g/L，2,3-丁二醇得率达到了理论得率的90.53％，生产强度1.56 g/(L·h)，检测不到副产物乳酸的生成，利于后提取工艺的进行和工业生产的应用。

Comparison of 2,3-butanediol production by several strains and optimization of the fermentation medium

Five Klebsiella pneumonia strains (including two strains whose genes for lactic acid were knocked out) were used to produce 2,3-butanediol, in which K. pneumonia HR521 LDH (gene for lactic acid was knocked out) was the best for the production, and then the fermentation medium was optimized by orthogonal design. The optimum compositions were as follows: glucose 90 g/L, (NH4)2HPO4 3 g/L, CLSP 6 g/L, sodium acetate 5 g/L, KCl 0.4 g/L, MgSO4 0.1 g/L, FeSO4·7H2O 0.02 g/L, MnSO4 0.01 g/L. Under the above conditions, final concentration of acetone and 2,3-butanediol could reach 37.46 g/L, 10 g/L higher than that under the initial conditions, the yield was 90.53% of the theory, and the productivity was 1.5 g/(L·h), and no lactic acid was detected, which could be benefit for the downstream processing and industrial application.