代谢甘油高产乳酸的菌种选育及培养基优化

Strain Screening for Bioconversion of Glycerol to Lactic Acid and Optimization of Culture Medium

摘要:

分离出一株可高效利用甘油生产乳酸的菌株, 经过生理生化和16S rDNA分子鉴定, 确定其属于大肠埃希氏菌, 命名为Escherichia coli AC-521。通过五因素四水平正交试验, 优化了其最佳发酵培养基成分为初始甘油70 g/L, 酵母粉4 g/L, 蛋白胨7 g/L, (NH4)2SO4 10 g/L, K2HPO4 2.5 g/L。利用该最佳条件的5 L发酵罐批式补料发酵实验表明: 该菌株发酵80 h后, 乳酸产量可达到74.5 g/L, 得率为0.87 mol/mol甘油。

Abstract:

A strain, Escherichia coli AC-521, which could efficiently covert glycerol to lactic acid, was isolated from soil samples. A series of morphological and biochemical characteristics and sequence analysis of 16S rDNA reveal that it belongs to Escherichia coli. Through orthogonal experiment of L16(45), the optimum medium compositions were determined as initial glycerol 70 g/L, yeast extract 4 g/L, peptone 7 g/L, (NH4)2SO4 10 g/L, and K2HPO4 2.5 g/L. The 5L fermenter fed-batch fermentation was performed under optimal conditions, giving 74.5 g/L lactic acid with a yield of 0.87 mol/mol glycerol after 80 hours.