文献类型：期刊文献

英文题名：Stepwise metabolic engineering of a plasmid-free Corynebacterium glutamicum for efficient production of γ-aminobutyric acid (GABA) by co-utilizing lignocellulosic feedstock-derived sugars

作者：Wang, Jie[1];Xu, Yingying[1];Song, Zhuolin[1];Zhang, Bin[1];Bao, Jie[1]

机构：[1]East China Univ Sci & Technol, State Key Lab Bioreactor Engn, 130 Meilong Rd, Shanghai 200237, Peoples R China

年份：2025

卷号：406

起止页码：281

外文期刊名：JOURNAL OF BIOTECHNOLOGY

收录：;EI(收录号：20253118887400);WOS:【SCI-EXPANDED(收录号:WOS:001542800100001)】；

基金：This research was supported by the National Key R & D Program of China (2023YFA0914400) , National Natural Science Foundation of China (32301269) , and the Yangfan Project of Science and Technology Committee of Shanghai Municipality (23YF1409900) , and the Key Technology R & D Program of the Science and Technology Commission of Shanghai Municipality 25HC2820200.

语种：英文

外文关键词：gamma-aminobutyric acid; Corynebacterium glutamicum; Plasmid free; Multiple-copy integration; Lignocellulose

摘要：gamma-aminobutyric acid (GABA) can be synthesized through plasmid-based expression of glutamate decarboxylase in L-glutamic acid producing Corynebacterium glutamicum strain. However, the addition of antibiotic to maintain the expression plasmid during the fermentation not only increases production and recovery costs, but also poses potential food safety hazards. In this study, a plasmid-free GABA producing C. glutamicum strain was constructed from C. glutamicum GJ04 chassis, which can produce L-glutamate by co-utilizing lignocellulose-derived glucose and xylose. Secretory glutamate decarboxylase was integrated into the genome of C. glutamicum GJ04 in three copies by replacing ldh, gabT, gabD genes. The metabolic flux in engineered C. glutamicum was further fine-tuned by knocking out aceA and gabP genes to enhance GABA production. The recombinant strain C. glutamicum GJ09 can produce 44.3 +/- 3.8 g/L GABA from 15 % (w/w) solids loading corncob residues hydrolysate with the yield and productivity of 0.45 g/g and 0.74 g/L/h. The highest GABA titer reached 63.4 g/L by fed-batch fermentation using corncob residues-derived syrup. This study provided a robust and plasmid-free C. glutamicum strain by stepwise metabolic engineering for industrial production of GABA from lignocellulosic feedstocks.