乳酸菌发酵甘蔗糖蜜产乳酸的培养条件优化

乳酸是有广泛应用的有机酸，廉价原料是降低乳酸生产成本的重要因素。以实验室前期筛选的植物乳杆菌sy4为出发菌株研究了利用甘蔗糖蜜生产乳酸的培养条件。在确定发酵温度和初始pH后，通过Plackett-Burman实验和中心复合实验优化乳酸发酵条件。结果表明：植物乳杆菌sy4乳酸发酵的最适条件为温度32℃、60h、初始pH 6.5；Plackett-Burman实验表明酵母提取物、糖蜜和碳酸钙是影响乳酸产量的主要因素；中心复合实验得到三因素的最优组合为：酵母提取物13.19g/L、糖蜜476.63g/L和碳酸钙134.82g/L，确定了最适发酵培养基。在此条件下乳酸产量为（145.53±1.24） g/L，与模型预测值147.23g/L接近。本研究为以甘蔗糖蜜为原料生产乳酸提供了技术支持。

Fermentation condition optimization for lactic acid production with cane molasses by Lactobacillus

Lactic acid is a widely used organic acid. Using the cheap raw material is the key factor for reducing the production cost of the lactic acid. Lactobacillus plantarum sy4, which was screened in our previous work, was used as an original strain for the lactic acid production with cane molasses. The fermentation conditions of the lactic acid were optimized with the Placket-Burman Design and the Central Composite Design after studying the fermentation temperatures and initial pH. The results showed that the optimal fermentation conditions for sy4 were 32℃, 60h, and initial pH 6.5. The results of Placket-Burman Design showed that the yeast extract, cane molasses and calcium carbonate were the main factors for the lactic acid production. And the results of the Central Composite Design showed that the optimal combination of those three factors were yeast extract 13.19g/L, cane molasses 476.63g/L and calcium carbonate 134.82g/L. The optimal fermentation medium was confirmed and the lactic acid production was (145.53±1.24)g/L, which was closed to the predicted value 147.23g/L. The research provided the technical support for future lactic acid production with the cane molasses.