大肠杆菌利用木糖发酵产琥珀酸的研究

Xylose Fermentation for Succinic Acid Production by Escherichia coli

目的:研究大肠杆菌以木糖为碳源发酵产琥珀酸。方法:首先比较了实验室保藏的7种野生型大肠杆菌利用木糖发酵产琥珀酸的产量和得率,结果:表明野生型菌株琥珀酸对木糖的得率集中在0.34g/g^0.53g/g之间,得率较低,副产物主要为乳酸、乙酸。然后选取其中2株菌(E.coli MG1655与E.coli C-1)进行基因敲除,构建了ldhA和pflB双基因缺失的MLB和CLB菌株,以减少副产物的积累。两阶段摇瓶发酵结果表明,琥珀酸得率从0.40g/g分别提高到了0.89g/g及0.90g/g,而产量分别从4.92g/L、5.58g/L提高到11.52g/L、11.81g/L。结论:通过基因敲除后,大肠杆菌能够利用木糖发酵产琥珀酸,琥珀酸得率可以达到0.90g/g。

Objective：The study was to produce succinic acid by xylose fermentation. Method： First, the production of succinic acid by seven kinds of wild - type E. coli preserved in our laboratory were compared. Result： It showed that the yield of succinic acid mainly con- centrated on O. 34g/g -0. 53g/g. The yield was quite low and the main byproducts were lactic acid and acetic acid. Then E. coli MG1655 and E. coli C - 1 were selected for gene knockout to reduce the accumulation of byproducts. The strains MLB （E. coli MG1655 A/dhA, Ap- fiB） and CLB（ E. coli C - 1 AldhA, ApflB） were construct. The two - stage fermentation showed the yield of succinic acid improved from 0. 40 g/g,0. 47 g/g to 0. 89 g/g,0. 90 gig while the production improved from 4. 92 g/L,5.58 g/L to 11.52 g/L,11.81 g/L, respective- ly. Conclusion ：It showed that through the gene knockout, succinic acid can be produced by Escherichia coli using xylose as the carbon source and the succinic acid yield was 0. 90 gig.