State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Bioresour Technol. 2023 Jun;378:128991. doi: 10.1016/j.biortech.2023.128991. Epub 2023 Mar 31.
Corynebacterium glutamicum was developed for efficient production of succinic acid from corn stover (CS) pretreated by concentrated-alkali under steam-assistant (CASA) conditions. First, C. glutamicum was engineered by 1) blocking the by-products pathways (deletion of ldh, pta-ackA, and cat), 2) enhancing the carbon flux to succinate (overexpression of pyc and ppc), and 3) releasing the end-product inhibition (overexpression of Ncgl0275). The recombinant strain produced 117.8 g/L succinate in fed-batch fermentation. Second, to fully utilize xylose in lignocellulosic hydrolysate, two xylose utilization pathways-the isomerase pathway and the Weimberg pathway-were introduced into the recombinant strain. Third, CS was pretreated by CASA with a higher sugars yield and a lower black liquid. Finally, 64.16 g/L of succinic acid was obtained from 150 g/L CASA-pretreated CS by engineered C. glutamicum. These results showed a succinate high-producing C. glutamicum strain using glucose and xylose simultaneously as well as an effective and environmentally acceptable pretreatment strategy.
谷氨酸棒杆菌被开发用于从经过蒸汽辅助浓碱预处理的玉米秸秆（CS）中高效生产琥珀酸。首先，通过 1）阻断副产物途径（ldh、pta-ackA 和 cat 的缺失），2）增强碳通量到琥珀酸（pyc 和 ppc 的过表达），3）释放终产物抑制（Ncgl0275 的过表达），对谷氨酸棒杆菌进行工程改造。重组菌在分批补料发酵中生产了 117.8 g/L 的琥珀酸。其次，为了充分利用木质纤维素水解液中的木糖，引入了两条木糖利用途径——异构酶途径和魏因伯格途径——到重组菌中。第三，采用 CASA 对 CS 进行预处理，提高了糖的得率，降低了黑液的含量。最后，通过工程化的谷氨酸棒杆菌从 150 g/L 的 CASA 预处理 CS 中获得了 64.16 g/L 的琥珀酸。这些结果表明，该方法利用葡萄糖和木糖同时生产琥珀酸，同时提供了一种有效且环境友好的预处理策略。
