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

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16SrDNA分子鉴定,确定其属于大肠埃希氏菌,命名为Escherichia coliAC-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70g/L,酵母粉4g/L,蛋白胨7g/L,(NH4)2SO410g/L,K2HPO42.5g/L。利用该最佳条件的5L发酵罐批式补料发酵实验表明:该菌株发酵80h后,乳酸产量可达到74.5g/L,得率为0.87mol/mol甘油。

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 opti- mum 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 5 L fermenter fed-batch fermentation was performed under op- timal conditions, giving 74.5 g/L lactic acid with a yield of 0.87 mol/mol glycerol after 80 hours.