1株乳酸生产菌的筛选及发酵培养基的优化

Screen of the Bacterial Strains for Lacti Acid Production and Optimization of its Fermentation Medium

[目的]为乳酸菌的发酵生产奠定基础。[方法]从14株耐碱微生物中筛选出1株性能优良的产乳酸菌LP3-3,并通过单因素试验对该菌发酵生产乳酸的培养基进行优化。[结果]产乳酸菌LP3-3经16S rRNA序列测定初步鉴定为金橙黄微小杆菌(Exiguobacteriumaurantiacum)。经优化,产乳酸菌LP3-3培养基中最佳碳源是葡萄糖,最佳氮源是酵母膏,酵母膏用量为1%,碳氮比为5。确定了其最佳发酵培养基组成:葡萄糖50.0 g/L,酵母膏10.0 g/L,蛋白胨4.0 g/L,乙酸钠(无水)2.0 g/L,柠檬酸三铵2.0 g/L,K2HPO4.H2O 2.0g/L,MgSO4.7H2O 0.2 g/L,MnCl2o4H2O 0.05 g/L,吐温80 1 ml/L,NaCl 40 g/L,初始pH为9.0。[结论]通过培养基的优化提高了产乳酸菌LP3-3的活力。

[Objective] The basis of the lactic acid fermentation was laid.[Method The bacterial strain LP3-3,which had a higher yield of lactic acid,was obtained from 14 alkali-resistant microorganisms.The medium for the LP3-3 fermentation was optimized with single-factor experiment.[Results] The results indicated that the LP3-3 was confirmed to be Exiguobacterium aurantiacum C/N based on the preliminary identification of 16S rRNA sequencing.The optimal experiment in its fermentation medium indicated the glucose was used as the source of carbon,the yeast extract with the amount of 1% was used as nitrogen and the ratio of C/N was 5∶1.And the best component in medium was the glucose was 50.0 g/L,the yeast extract was 10.0 g/L,the peptone was 4.0 g/L,the sodium acetate（anhydrous）2.0 g/L,the ammonium citrate was 2.0 g/L,K2HPO4·H2O was 2.0 g/L,MgSO4·7H2O was 0.2 g/L,MnCl2·4H2O was 0.05 g/L,the Twain 80 was 1 ml/L,NaCl was 40 g/L and the initial pH value was 9.0.[Conclusion] The activity of LP3-3 in lactic acid fermentation was raised in the optimal medium.