利用糖蜜和玉米浆作为唯一营养源，通过工程改造和适应性进化生产 L-乳酸的大肠杆菌 W。
Engineering and adaptive evolution of Escherichia coli W for L-lactic acid fermentation from molasses and corn steep liquor without additional nutrients.
机构信息
Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Key Laboratory of Fermentation Engineering, Ministry of Education, College of Bioengineering, Hubei University of Technology, Wuhan 430068, PR China.
出版信息
Bioresour Technol. 2013 Nov;148:394-400. doi: 10.1016/j.biortech.2013.08.114. Epub 2013 Aug 27.
The D-lactic acid producing strain, Escherichia coli HBUT-D, was reengineered for L(+)-lactic acid fermentation by replacing the D-lactate dehydrogenase gene (ldhA) with an L(+)-lactate dehydrogenase gene (ldhL) from Pedicoccus acidilactici, followed by adaptive evolution in sucrose. The resulting strain, WYZ-L, has enhanced expression of the sucrose operon (cscA and cscKB). In 100 g L(-1) of sucrose fermentation using mineral salt medium, WYZ-L produced 97 g L(-1) of l(+)-lactic acid, with a yield of 90%, a maximum productivity of 3.17 g L(-1)h(-1) and an optical purity of greater than 99%. In fermentations using sugarcane molasses and corn steep liquor without additional nutrients, WYZ-L produced 75 g L(-1) of l(+)-lactic acid, with a yield of 85%, a maximum productivity of 1.18 g L(-1)h(-1), and greater than 99% optical purity. These results demonstrated that WYZ-L has the potential to use waste molasses and corn steep liquor as a resource for L(+)-lactic acid fermentation.
产 D-乳酸的大肠杆菌 HBUT-D 菌株通过用来自戊糖片球菌的 L(+)-乳酸脱氢酶基因（ldhL）替换 D-乳酸脱氢酶基因（ldhA），并在蔗糖中进行适应性进化，被重新设计用于 L(+)-乳酸发酵。得到的菌株 WYZ-L 蔗糖操纵子（cscA 和 cscKB）的表达增强。在使用无机盐培养基的 100 g/L 蔗糖发酵中，WYZ-L 生产了 97 g/L 的 L(+)-乳酸，得率为 90%，最大生产力为 3.17 g/L/h，光学纯度大于 99%。在不添加额外营养物质的甘蔗废糖蜜和玉米浆发酵中，WYZ-L 生产了 75 g/L 的 L(+)-乳酸，得率为 85%，最大生产力为 1.18 g/L/h，光学纯度大于 99%。这些结果表明，WYZ-L 有可能利用废糖蜜和玉米浆作为 L(+)-乳酸发酵的资源。
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