Lactobacillus fermentum F6的增殖培养基优化及高密度发酵的研究

对分离自少数民族传统乳制品中的Lactobacillus fermentum F6菌种的增殖培养基进行优化,并对其高密度发酵条件进行探索。通过测定不同组成培养基中菌体在600nm波长下的光密度和发酵液在不同发酵条件下的活菌数,得到最适增殖培养基配方及其高密度发酵条件。增殖培养基配方为:蔗糖62.0g/L、酵母粉35.5g/L、大豆蛋白胨12.0g/L、柠檬酸1.35g/L、柠檬酸钠22g/L、MgSO4·7H2O2g/L、MnSO4·5H2O100mg/L、Tween-801g/L。在5L发酵罐中,Lactobacillus fermentum F6经优化发酵条件,其活菌数可达到2.30×1010CFU/mL,加入保护剂经冷冻干燥后活菌数可达到1.45×1011CFU/g,存活率为79.11%。中试培养液中活菌数可达1.02×1010CFU/mL,存活率为58%。以上优化的增殖培养基和高密度发酵条件为Lactobacillus fermentum F6的工业化生产奠定了基础。

Study on the Optimization of Enrichment Medium of Lactobacillus fermentum F6 and its High-density Cultivation

To optimize the enrichment medium components and the high-density cultivation procedure of Lactobacillus fermentum F6,this was isolated from traditional dairy products of minority nationalities.Detected OD600 （optical density under 600 nm） in different medium and bacterial colonies were counted under different high-density cultivation conditions.The composition of enrichment medium for Lactobacillus fermentum F6 was as follows： sucrose 62.0 g/L,yeast extract 35.5 g/L,soy peptone 12.0 g/L,citric acid 1.35 g/L,citrate sodium 22 g/L,MgSO4·7H2O 2 g/L,MnSO4·5H2O 100 mg/L,and Tween-80 1.0 g/L.After high-density cultivation in enrichment medium with optimized conditions,the living cells of fermentation broth and powder were 2.30×1010 CFU/mL and 1.45×10^11 CFU/g,respectively.The survival rate after freeze-drying with cryoprotector was 79.11 %.The count of living cells in fermentation broth of plot plant scale test could reach to 1.02×10^10 CFU/mL,the survival rate was 58 %.The result can provide some useful data to the industrial application of Lactobacillus fermentum F6.