caa a22 4500 605503761 CHVBK 20210128100612.0 cr unu---uuuuu 210128e20150201xx s 000 0 eng 10.1007/s00253-014-6243-0 doi (NATIONALLICENCE)springer-10.1007/s00253-014-6243-0 l -Serine overproduction with minimization of by-product synthesis by engineered Corynebacterium glutamicum [Elektronische Daten] [Qinjian Zhu, Xiaomei Zhang, Yuchang Luo, Wen Guo, Guoqiang Xu, Jinsong Shi, Zhenghong Xu] The direct fermentative production of l-serine by Corynebacterium glutamicum from sugars is attractive. However, superfluous by-product accumulation and low l-serine productivity limit its industrial production on large scale. This study aimed to investigate metabolic and bioprocess engineering strategies towards eliminating by-products as well as increasing l-serine productivity. Deletion of alaT and avtA encoding the transaminases and introduction of an attenuated mutant of acetohydroxyacid synthase (AHAS) increased both l-serine production level (26.23g/L) and its productivity (0.27g/L/h). Compared to the parent strain, the by-products l-alanine and l-valine accumulation in the resulting strain were reduced by 87% (from 9.80 to 1.23g/L) and 60% (from 6.54 to 2.63g/L), respectively. The modification decreased the metabolic flow towards the branched-chain amino acids (BCAAs) and induced to shift it towards l-serine production. Meanwhile, it was found that corn steep liquor (CSL) could stimulate cell growth and increase sucrose consumption rate as well as l-serine productivity. With addition of 2g/L CSL, the resulting strain showed a significant improvement in the sucrose consumption rate (72%) and the l-serine productivity (67%). In fed-batch fermentation, 42.62g/L of l-serine accumulation was achieved with a productivity of 0.44g/L/h and yield of 0.21g/g sucrose, which was the highest production of l-serine from sugars to date. The results demonstrated that combined metabolic and bioprocess engineering strategies could minimize by-product accumulation and improve l-serine productivity. Springer-Verlag Berlin Heidelberg, 2014 l -Serine production nationallicence Acetohydroxyacid synthase nationallicence Transaminases nationallicence Corn steep liquor nationallicence Corynebacterium glutamicum nationallicence Zhu Qinjian School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut Zhang Xiaomei School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut Luo Yuchang School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut Guo Wen School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut Xu Guoqiang School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut Shi Jinsong School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut Xu Zhenghong School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/4(2015-02-01), 1665-1673 0175-7598 99:4<1665 2015 99 253 https://doi.org/10.1007/s00253-014-6243-0 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00253-014-6243-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhu Qinjian School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut NATIONALLICENCE 700 1- Zhang Xiaomei School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut NATIONALLICENCE 700 1- Luo Yuchang School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut NATIONALLICENCE 700 1- Guo Wen School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut NATIONALLICENCE 700 1- Xu Guoqiang School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut NATIONALLICENCE 700 1- Shi Jinsong School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut NATIONALLICENCE 700 1- Xu Zhenghong School of Pharmaceutics Science, Jiangnan University, 214122, Wuxi, People's Republic of China aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/4(2015-02-01), 1665-1673 0175-7598 99:4<1665 2015 99 253