大肠杆菌突变株QQS101发酵生产琥珀酸初步研究

琥珀酸是一种具有重要应用价值的生物基平台化合物。对大肠杆菌focA-pflB ldhA突变株QQS101在严格厌氧条件下生长和葡萄糖代谢能力进行了考察,比较分析了葡萄糖与大肠杆菌混合酸发酵产物的单位碳的还原程度,认为非严格厌氧条件有利于QQS101发酵葡萄糖积累琥珀酸,进一步对有氧生长碳源进行了对比试验的结果表明,以木糖支持有氧生长,QQS101摇瓶发酵39 h消耗葡萄糖37.6 g/L,琥珀酸的产量达到31.01 g/L,摩尔产率为1.258 mol Succinate/mol Glucose。发酵过程中,丙氨酸的添加能够提高琥珀酸的摩尔产率。

Succinate Production from Escherichia coli Mutant QQS101 Fermentation

Succinate is an important bio-based platform molecule. In the present work, the growth and glucose metabolism of Escherichia coli mutant QQS101 with the deficiency of formate transporter A (focA), formate-pyruvate lyase (pflB) and lactate dehydrogenase (ldhA) under strict anaerobic condition were investigated. The degree of reduction per carbon of glucose and the products of E. coli mix-acids fermentation were compared, and then recognized that non-strict anaerobic condition favored QQS101 producing succinate from glucose. Furthermore, effects of the carbon sources for aerobic growth on fermentation were performed. Results showed that QQS101 could accumulate succinate with a concentration of 31.01 g/L with a yield of 1.258 mol Succinate/mol Glucose, when growing on xylose as the aerobic substrate. During the fermentation, addition of alanine could enhance the molar yield of succinate to glucose utilized.