State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, People's Republic of China.
J Ind Microbiol Biotechnol. 2014 Sep;41(9):1443-50. doi: 10.1007/s10295-014-1476-6. Epub 2014 Jul 6.
L-Serine is a nonessential amino acid, but plays a crucial role as a building block for cell growth. Currently, L-serine production is mainly dependent on enzymatic or cellular conversion. In this study, we constructed a recombinant Escherichia coli that can fermentatively produce L-serine from glucose. To accumulate L-serine, sdaA encoding the L-serine dehydratase, iclR encoding the isocitrate lyase regulator, and arcA encoding the aerobic respiration control protein were deleted in turn. In batch fermentation, the engineered E. coli strain YF-5 exhibited obvious L-serine accumulation but poor cell growth. To restore cell growth, aceB encoding the malate synthase was knocked out, and the engineered strain was then transformed with plasmid that overexpressed serA (FR) , serB, and serC genes. The resulting strain YF-7 produced 4.5 g/L L-serine in batch cultivation and 8.34 g/L L-serine in fed-batch cultivation.
L-丝氨酸是一种非必需氨基酸，但作为细胞生长的构建块起着至关重要的作用。目前，L-丝氨酸的生产主要依赖于酶或细胞转化。在这项研究中，我们构建了一株能够从葡萄糖发酵生产 L-丝氨酸的重组大肠杆菌。为了积累 L-丝氨酸，依次敲除编码 L-丝氨酸脱水酶的 sdaA、编码异柠檬酸裂解酶调节蛋白的 iclR 和编码需氧呼吸控制蛋白的 arcA。在分批发酵中，工程大肠杆菌菌株 YF-5 表现出明显的 L-丝氨酸积累，但细胞生长不良。为了恢复细胞生长，敲除编码苹果酸合酶的 aceB，并将过表达 serA（FR）、serB 和 serC 基因的质粒转入工程菌。得到的菌株 YF-7 在分批培养中产生 4.5 g/L 的 L-丝氨酸，在补料分批培养中产生 8.34 g/L 的 L-丝氨酸。
