产高光学纯度L-乳酸菌株HY-38发酵培养基优化

以产L-乳酸光学纯度为99.3%的粪肠球菌（Enterococcus faecium）HY-38作为出发菌株，通过Plackett-Burman试验设计确定影响L-乳酸的产量的主要因素，筛选出3个有显著影响效应的因素，分别为葡萄糖、酵母膏及乙酸钠，最陡爬坡试验逼近影响因素最佳值区域，采用Box-Behnken设计及响应面分析对L-乳酸发酵培养基成分进行优化。结果表明，L-乳酸发酵培养基成分确定为葡萄糖148 g/L、酵母膏12.4 g/L、碳酸钙80 g/L、乙酸钠5.0 g/L、磷酸二氢钾1.0 g/L、硫酸镁1.2 g/L、硫酸锰0.04 g/L，在此条件下，L-乳酸的产量达到134.7g/L，比优化前（108.3 g/L）提高了24.3%。

Optimization of fermentation medium for high optical purity L-lactic acid production by strain HY-38

Using the Enterococcus faecium HY-38 with 99.3% optical purity L-lactic acid as original strain, the main factors influencing the L-lactic acid yield were determined by Plackett-Burman experiments. The three factors with significant effect were screened, including glucose, yeast extract and sodium acetate, and optimum value of the main factors were determined steepest ascent path experiments. The results showed that the optimum components of L-lactic acid fermentation medium were as followed: glucose 148 g/L, yeast extract 12.4 g/L, CaCO3 80 g/L, sodium acetate 5.0 g/L, KH2PO4 1.0 g/L, MgSO4 1.2 g/L and MnSO4 0.04 g/L. Under the conditions, the yield of L-lactic acid could reach 134.7 g/L, which was 24.3% higher than that of before optimization (108.3 g/L).