Ma Ning, Zhu Kangjia, Mao Yin, Deng Yu
National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, Jiangsu, China.
Sheng Wu Gong Cheng Xue Bao. 2018 Feb 25;34(2):224-234. doi: 10.13345/j.cjb.170209.
Glycolic acid is an important industrial compound. To improve glycolic acid yield, we knocked out ldhA (lactate dehydrogenase) in Escherichia coli MG1655 (DE3) to get the strain Mgly1. Then, we regulated expression levels of isocitrate lyase (aceA), glyoxylic acid reductase (ycdW) and isocitrate dehydrogenase kinase/phosphorylase (aceK) that are key enzymes of glycolate synthesis pathway. The yield of glycolic acid increased to 0.326 g/g glucose (38.3% of the theoretical yield) by overexpressing citrate synthase (gltA). Then we knocked out glcB and aceB (malate synthase) in Mgly1. The engineering strain Mgly335 was obtained and the yield of glycolic acid reached 0.522 g/g glucose (61.4% of the theoretical yield).
乙醇酸是一种重要的工业化合物。为提高乙醇酸产量，我们敲除了大肠杆菌MG1655(DE3)中的ldhA(乳酸脱氢酶)以获得菌株Mgly1。然后，我们调节了乙醇酸合成途径关键酶异柠檬酸裂解酶(aceA)、乙醛酸还原酶(ycdW)和异柠檬酸脱氢酶激酶/磷酸酶(aceK)的表达水平。通过过表达柠檬酸合酶(gltA)，乙醇酸产量提高到0.326 g/g葡萄糖(理论产量的38.3%)。然后我们在Mgly1中敲除了glcB和aceB(苹果酸合酶)。获得了工程菌株Mgly335，乙醇酸产量达到0.522 g/g葡萄糖(理论产量的61.4%)。
