1株能利用高粱汁产L-乳酸的菌株鉴定及培养基优化

Optimization of Media and Identification of Microorganism Utilizing Sorghum Juice to Produce L-Lactic Acid

以产L-乳酸的菌株A2为对象,采用16S rRNA基因测序法结合菌株的表型特征进行鉴定,以甜高粱汁为主要培养基质,采用响应面设计软件对该菌种的发酵培养基进行优化。结果表明,A2菌株为Lactobacillus plantarum S4,优化得到的甜高粱汁培养基配比为甜高粱汁327. 83 g/L,蛋白胨1. 67 g/L,磷酸氢二钾4. 7 g/L,硫酸锰0. 17 g/L,在此培养基配比下,Lactobacillus plantarum S4厌氧发酵68 h后,L-乳酸产量达(61. 20±1. 36) g/L,L-乳酸/葡萄糖转化率(90. 74±2. 28)%,L-乳酸/蔗糖转化率(47. 20±1. 81)%。

In this study a L-lactic acid producing strain A2 was used as a target to carry out phenotypic characterization adopting 16S rRNA gene sequencing, and carried out the fermentation medium optimization taking sweet sorghum juice as main culturing stroma, and using Response Surface Designing Software. The results showed that the strain A2 was Lactobacillus plantarum S4. The optimized media proportion of different elements contained： sweet sorghum juice 327.83 g/L, peptone 1.67 g/L, K 2HPO 4 4.7 g/L, MnSO 4·4H 2O 0.17 g/L. Based on this proportion of media, 68 h after anaerobic fermentation, the yield of L-lactic acid was as high as（61.20±1.36） g/L, the L-lactic acid/glucose conversion rate was （90.74±2.28）%, L-lactic acid/sucrose conversion rate was （47.20±1.81）%.