基于底物消耗规律优化乳酸乳球菌增殖发酵工艺  

Optimization of Lactococcus lactis enrichment fermentation process based on substrate consumption law

作　　者：胡双露 毛丙永[1] 唐鑫 张秋香[1] 崔树茂[1] 张灏[1] HU Shuanglu;MAO Bingyong;TANG Xin;ZHANG Qiuxiang;CUI Shumao;ZHANG Hao(School of Food Science and Technology,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学食品学院,江苏无锡214122

出　　处：《食品与发酵工业》2023年第23期41-49,共9页Food and Fermentation Industries

基　　金：国家自然科学基金项目(32172173)。

摘　　要：为了提高乳酸乳球菌发酵生物量,该文首先筛选了最优碳氮源,分析了乳酸乳球菌偏好利用的氮源特征,定向制备了酪蛋白肽,进一步分析酪蛋白肽的添加对菌株增殖的影响;然后通过测定菌株生长速率被抑制时的碳氮消耗比和耐渗透压能力确定了初始发酵培养基的碳氮源添加比例和添加量。结果表明,葡萄糖是乳酸乳球菌的最佳碳源,酪蛋白肽和酵母浸粉FM 803以1∶2的质量比复合为最佳氮源,进一步优化微量元素的添加量和恒pH分批培养策略,得到最优培养基和培养工艺。乳酸乳球菌CCFM 1093的最优培养基:葡萄糖137 g/L、复合氮源53 g/L、MgSO_(4)·7H_(2)O 0.043 g/L、MnSO_(4)·H_(2)O 0.03 g/L、吐温-801 mL/L;乳酸乳球菌CCFM 1032最优培养基:葡萄糖106 g/L、复合氮源51 g/L、MgSO_(4)·7H_(2)O 0.043 g/L、MnSO_(4)·H_(2)O 0.03 g/L、吐温-801 g/L,活菌数分别可达到(1.01±0.06)×10^(12)CFU/mL和(9.78±0.38)×10^(11)CFU/mL,是MRS培养基静置培养的12.6倍和12倍。该研究结果将会显著提高乳酸乳球菌的工业生产效率。Lactococcus lactis is widely used in food,medicine and other fields,which is also one of the common starters in the dairy industry.The strains must reach a certain number of viable bacteria in order to exert the corresponding effect in vivo,which requires high culture density by optimizing the culture medium and culture process.Most of the traditional culture models are constant pH batch culture,but this model has two major problems:low substrate utilization and osmolarity inhibition.This leads to the difficulty of breaking the 1011 CFU/mL level of viable bacteria in the fermentation broth.The amount of substrate in the medium is a direct determinant of the final biomass,but when the concentration of substrate in the initial medium is too high,the osmotic pressure inhibition may result in slow or even stopped growth of the strain.Finding a balance between the two factors has become a key issue.Therefore,two strains of Lactococcus lactis were selected to study the effects of substrate type,substrate amount and culture process to improve the fermentation biomass.In this study we firstly screened the carbon and nitrogen sources in the medium and found that glucose is the most suitable carbon source for strain proliferation.Monosaccharides are more easily absorbed and utilized.The characteristics of nitrogen source were then studied to find that L.lactis prefers to utilize.The results showed that L.lactis preferred to use Angel®yeast extract FM803,which is rich in peptides with small molecules.In order to prepare the nitrogen source rich in small molecular peptides,casein was chosen as a substrate and trypsin and papain complex were chosen as enzymes for enzymatic digestion.Further analysis of the effect of casein peptide addition on strain proliferation were studied.When casein peptide and yeast extract FM803 were compounded in the ratio of 1∶2,the highest biomass was achieved.The above strategy resulted in the viable counts of(6.80±0.46)×1011 and(6.31±0.29)×1011 CFU/mL of the two strains,respectively,which w

关 键 词：乳酸乳球菌 氮源 高密度培养 渗透压 

分 类 号：TS201.3[轻工技术与工程—食品科学]