L-乳酸发酵的代谢调控育种及发酵影响因素的研究

The Metabolic Control Breeding of L-Lactic Acid Fermentation and Optimization of Media and Cultivation Conditions

摘要:

以嗜热乳杆菌(Lactobacillus Thermophilus ATCC8317)为出发菌，采用乙酸-乙酸钠平板为初筛方法，通过复合诱变乳酸产量提高到原来的3.1倍。培养基碳源为玉米粉糖化液，混合氮源为麦芽粉30g/L、蛋白胨5g/L。根据不同温度下细胞比生长速率及产物比生成速率的变化，确定了分阶段控制温度的策略：即在发酵前16h控制温度48℃、后44h控制温度54℃。L-乳酸产量达到135g/L，乳酸的对糖转化率为95%，平均产酸速率为2.25g/(L·h)。

Abstract:

Based on the strain breeding theory and metabolic engineering theory, A high-yield mutant of Lactobacillus Thermophilus ATCC8317 was obtained through the compound inducements by the original Acetic acid-Sodium acetate plate and the productivity increased 210%.The best media components included saccharifying corn,malt powder 30g/L,peptone 5g/L.Based on the variety of specific cell growth rate and specific L-lactic acid production rate at different temperatures, the strategy of temperature control was obtained. The total product of L-lactic acid reached 135g/L besides the rate of glucose consumed and the average L-lactic acid productivity were up to 95% and 2.25g/(L·h) respectively.