谷氨酸棒杆菌工程菌产生L-苹果酸的发酵工艺优化

Optimization of fermentation conditions for L-malic acid produced by engineering Corynebacterium glutamicum M5

研究了碳源、氮源、乙酸盐、碳酸氢钠、温度、氧气等诸多因素和条件变化,对于谷氨酸棒杆菌工程菌株M5(C.glutamicum ATCC13032 M5)发酵产生L-苹果酸产量的影响。L-苹果酸的检测采用高效液相色谱法。实验结果显示,以5%葡萄糖、0.5%NaAce、0.5%(NH_4)_2SO_4、0.15%KH_2PO_4、0.05%Mg SO_4·7H_2O、0.02%CaCl_2为发酵培养基,NaHCO_3调节pH 7.0,接种量2.5%,30℃自控摇床好氧发酵36 h后,转换成限氧发酵72 h,L-苹果酸产量可达到25.2 g/L,糖酸转化率为72%。实验结果验证了工程菌M5的基因工程改造是成功的,有希望成为发酵生产L-苹果酸的新菌种。

In this paper,engineering strain C.glutamicum ATCC13032 M5 was taken as the experimental strain. In order to improve the yield of L-malic acid,the fermentation process and different nutritional conditions were studied,such as ：carbon source,nitrogen source,acetate,sodium bicarbonate,temperature,oxygen,etc. The L-malic acid was detected by high performance liquid chromatography. The results showed that the optimal medium composition were determined as follows（g/L）：glucose 50,Na Ace 5,（NH_4）_2SO_4 5,KH_2PO_4 1.5,MgSO_4· 7H_2O 0.5,CaCl_2 0.2,pH was adjusted to 7.0 with Na HCO_3,aerobic fermentation with 2.5% of inoculation,at 30℃ for 36 h by auto oxygen fermentation shaker,then changed into limited oxygen fermentation for 72 h by the controlled shaker. The yield of L-malic acid could reach to 25.2 g/L,sugar acid conversion was 72%. The results proved that the transformation of the engineering strain M5 was successful,and it has the potential to become a new strain used for fermenting L-malic acid.