L-赖氨酸全营养流加发酵工艺的研究

Study on Technology of Total Nutrient Feeding Fermentation of L-Lysine

为解决谷氨酸棒杆菌LS260发酵产L-赖氨酸后期产率下降的问题,全营养流加策略是在发酵过程中向发酵液中流加菌体生长及生产所需的全部营养物质以维持菌体活力的一种方法。实验采用梯度浓度全营养恒速流加策略,解决了发酵中后期菌体产酸能力不足的问题,在发酵底料培养基浓度不变的情况下,采用流加浓度为50%底料培养基的方法,L-赖氨酸产量提升到235 g/L;然后分析在菌体生长的不同阶段流加全营养对发酵过程中产酸速率的影响,为提高菌体快速生长期的生长速率和高速产酸期的产酸速率,分别在发酵5,10,15,20 h流加全营养,在发酵10 h流加50%全营养,菌体的高速产酸期延长了3 h,L-赖氨酸产量达到255 g/L,较优化前提高了52.7%,糖酸转化率为67%,较优化前提高了13%。

In order to solve the problem of the decline of yield of L-lysine produced by Corynebacterium glutamicum LS260 in the late stage of fermentation,the total nutrient feeding strategy is a method to maintain the vitality of bacteria by adding all the nutrients required for bacteria growth and production into the fermentation broth in the process of fermentation.In the experiment,the gradient concentration total nutrient constant speed feeding strategy is adopted to solve the problem of insufficient acid production capacity of bacteria in the middle and late stages of fermentation.Under the condition of constant fermentation substrate medium concentration,the L-lysine yield increases to 235 g/L by feeding 50%substrate medium,and then the effect of feeding total nutrient at different stages of bacteria growth on the acid production rate in the fermentation process is analyzed,in order to improve the growth rate of the bacteria in the rapid growth period and the acid production rate in the high-speed acid production period,feeding total nutrient at 5,10,15,20 hours of fermentation and 50%total nutrient at 10 hours of fermentation respectively,the high-speed acid production period of the bacteria is prolonged by 3 hours,the L-lysine yield reaches 255 g/L,which is 52.7%higher than that before optimization,and the sugar and acid conversion rate is 67%,which is 13%higher than that before optimization.