删除odhA或pyc可提高重组谷氨酸棒杆菌中γ-氨基丁酸及其前体L-谷氨酸的产量。
Deletion of odhA or pyc improves production of γ-aminobutyric acid and its precursor L-glutamate in recombinant Corynebacterium glutamicum.
作者信息
Wang Nannan, Ni Yalan, Shi Feng
机构信息
State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China,
出版信息
Biotechnol Lett. 2015 Jul;37(7):1473-81. doi: 10.1007/s10529-015-1822-4. Epub 2015 Mar 24.
OBJECTIVES
To enhance γ-aminobutyric acid (GABA) production in recombinant Corynebacterium glutamicum, metabolic engineering strategies were used to improve the supply of the GABA precursor, L-glutamate.
RESULTS
C. glutamicum ATCC13032 co-expressing two glutamate decarboxylase genes (gadB1 and gadB2) was constructed in a previous study Shi et al. (J Ind Microbiol Biotechnol 40:1285-1296, 2013) to synthesize GABA from endogenous L-glutamate. To improve its L-glutamate supply, new strains were constructed here. First, the odhA and pyc genes were deleted separately. Then, a gadB1-gadB2 co-expression plasmid was transferred into ΔodhA, Δpyc, and ATCC13032, resulting in recombinant strains SNW201, SNW202, and SNW200, respectively. After fermenting for 72 h, GABA production increased to 29.5 ± 1.1 and 24.9 ± 0.7 g/l in SNW201 and SNW202, respectively, which was significantly higher than that in SNW200 (19.4 ± 2.6 g/l). The GABA conversion ratios of SNW201 and SNW202 reached 0.98 and 0.96 mol/mol, respectively.
CONCLUSION
The recombinant strains SNW201 and SNW202 can be used as candidates for GABA production.
目的
为提高重组谷氨酸棒杆菌中γ-氨基丁酸（GABA）的产量，采用代谢工程策略来改善GABA前体L-谷氨酸的供应。
结果
在之前的一项研究中（Shi等人，《工业微生物与生物技术杂志》40:1285 - 1296，2013年）构建了共表达两个谷氨酸脱羧酶基因（gadB1和gadB2）的谷氨酸棒杆菌ATCC13032，用于从内源性L-谷氨酸合成GABA。为改善其L-谷氨酸供应，在此构建了新菌株。首先，分别缺失odhA和pyc基因。然后，将gadB1 - gadB2共表达质粒转入ΔodhA、Δpyc和ATCC13032，分别得到重组菌株SNW201、SNW202和SNW200。发酵72小时后，SNW201和SNW202中的GABA产量分别增加到29.5±1.1和24.9±0.7 g/l，显著高于SNW200（19.4±2.6 g/l）。SNW201和SNW202的GABA转化率分别达到0.98和0.96 mol/mol。
结论
重组菌株SNW201和SNW202可作为GABA生产的候选菌株。
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