摘要
保加利亚乳杆菌是酸奶发酵剂和益生菌制剂的重要菌种,其高密度培养对于提高菌种在应用产品生产中的效率具有重要的现实意义。葡萄糖浓度和发酵pH是影响保加利亚乳杆菌生长的关键因子,底物葡萄糖被转化为细胞菌体和主要代谢产物乳酸,探究葡萄糖消耗速率与表征乳酸生成的发酵pH下降速率的关系,是研究保加利亚乳杆菌代谢流方向的重要方法。该实验通过培养基组成和培养条件对保加利亚乳杆菌生长的影响进行研究,同时对葡萄糖消耗速率-pH降低速率相关模型研究,并基于底物质量守恒定律建立了一条基于pH下降速率的保加利亚乳杆菌高密度培养的反馈补料发酵策略。通过化学中和法控制发酵pH为6.0~5.0,基于pH下降速率进行反馈补料将葡萄糖质量浓度控制在8~2 g/L,发酵液的活菌数达到3.6×10^(9)CFU/mL,是批次分批培养的2.4倍。该策略的应用结果为提高保加利亚乳杆菌的工业化生产效率提供参考。
Lactobacillus bulgaricus is an essential strain of yogurt starter and probiotic preparations.Its high-density culture has practical significance for improving production efficiency of the strain applied products.Glucose concentration and fermentation pH are key factors affecting the growth of Lactobacillus bulgaricus.The substrate glucose is converted into cellular bodies,and the main metabolite is lactic acid.In particular,the study of the rate of glucose consumption in relation to the rate of decrease in fermentation pH characterizing lactic acid production is an essential method to study the direction of metabolic flow in Lactobacillus bulgaricus.In this study,the effect of medium composition and culture conditions on the growth of Lactobacillus bulgaricus and the correlation model of glucose consumption ratepH decrease rate was studied.Based on the conservation law of substrate mass,a feedback strategy for a high-density culture of Lactobacillus bulgaricus based on the pH decrease rate was established.The pH of fermentation was controlled within the interval of 6.0-5.0 using the chemical neutralization method,and the glucose concentration was controlled within the interval of 8-12 g/L by feedback feeding based on the pH decrease rate.The number of live bacteria in the fermentation liquid reached 3.6×10^(9) CFU/mL,2.4 times that of batch culture.The application results of this strategy provide a reference for improving the industrial production efficiency of Lactobacillus bulgaricus.
作者
陈晓岑
徐岩
刘彦民
李晓军
穆晓清
CHEN Xiaocen;XU Yan;LIU Yanmin;LI Xiaojun;MU Xiaoqing(Laboratory of Brewing Microbiology and Applied Enzymology,Key Laboratory of Industrial Biotechnology of Ministry of Education,School of Biotechnology,Jiangnan University,Wuxi 214122,China;Suqian Jiangnan University Institute of Industrial Technology,Suqian 223800,China;Inner Mongolia Shuang Qi Pharmaceutical Co.Ltd.,Hohhot 010010,China)
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2024年第5期7-13,共7页
Food and Fermentation Industries
基金
国家重点研发计划项目(2021YFC2100100)
国家自然科学基金项目(21336009,21176103)
轻工业技术与工程国家一级学科计划项目(LITE2018-09)。
关键词
保加利亚乳杆菌
反馈补料策略
高密度培养
区间pH培养
比生长速率
Lactobacillus bulgaricus
feedback feeding strategy
high-density culture
interval pH culture
specific growth rate