The production of lactic acid from glucose and xylose by thermophilic Lactobacillus (LG-1-5 and LG-2-2) was investigated. Batch experiments were carried out under facultative anaerobic conditions. When 180 g/L of glucose was used as the single carbon source, the concentration of L-lactic acid increased significantly and could achieved as high as 144 g/L after 72 h of fermentation by thermophilic Lactobacillus LG-1-5. While in the case of using 80 g/L xylose as the single carbon source, L-lactic acid just reached 64 g/L by thermophilic Lactobacillus LG-2-2. The conversion rate was 85.2% and 86.5% , respectively. When both of glucose and xylose were used as co-substrate (20 g/L glucose and 40 g/L xylose) , 25 g/L of L-lactic acid was obtained. The results showed that the reason for the lower yield and productivity of L-lactic from the co-fermentation with glucose and xylose due to the competitive inhibition, if compared with that of only using glucose or xylose as the fermentation substrate.%对两株嗜热乳杆菌thermophilic Lactobacillus LG-1-5、LG-2-2利用木糖和葡萄糖发酵生产L-乳酸进行了研究.菌株LG-1-5利用180 g/L葡萄糖发酵72 h后,其L-乳酸浓度达到144 g/L.而菌株LG-2-2发酵80 g/L木糖,其L-乳酸的产量为64 g/L.两株菌的糖酸转化率分别为85.2％和86.5％.共发酵葡萄糖(20g/L)和木糖(40 g/L)时,LG-1-5的L-乳酸的产量为25 g/L.实验表明,由于抑制因子的存在,在共发酵葡萄糖和木糖时,乳酸的产率明显低于以葡萄糖或木糖作为唯一碳源,但对葡萄糖和木糖的高效利用使菌株LG-1-5和LG-2-2仍有很大的工业应用价值.
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