干酪乳杆菌产L-乳酸发酵条件的研究

Studies on L-Lactic acid fermention conditions of lactobacillus casei

通过单因子实验和正交试验确定干酪乳杆菌突变菌株LAB3的最佳培养基和最佳培养条件,优化该菌株的生长条件.优化发酵培养基为(g/L):蔗糖120,玉米浆25,MgSO4.7H2O 0.3,MnSO4.4 H2O 0.01,FeSO4.7H2O 0.01,乙酸钠5,吐温80 1 mL.优化培养条件为:10%接种量,温度42℃,装液量50 mL/250 mL.静置培养72 h,一次性添加碳酸钙5%.在此优化基础上进行发酵,LAB3产乳酸量为85 g/L,产量较优化前提高了63%.

The optimal fermentation medium and fermentation conditions of the strain LAB3 were studied by means of single factor and the orthogonal design, that to optimize best condition of the strain. The optimal fermentation medium is consisted of the following composition（g/L） ：cane sugar 120,corn steep liquor 25, MgSO4 · 7H2O 0. 3,MnSO4 · 4H2O 0.01 ,FeSO4 · 7H2O 0.01 ,Sodium acetate 5,Polysorbate 80 1 mL. The optimal fermentation conditions are： 10% inoculum,42℃,50 mL in 250 mL total volum,still-culture 72 hours, CaCO3 5.9% which is added to the broth one-off. Fermentation on this optimal condition, the output of lactic acid is 85 g/L,the yield increases 63% as before optimize.