Abstract
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.
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Acknowledgments
The authors thank the ‘‘Program of State Key Laboratory of Food Science and Technology” (contract no. SKLF-ZZB-201405) and ‘‘Fundamental Research Funds for the Central Universities” (contract no. JUSRP51303A) for financial support.
Supporting information
Supplementary Table 1—Primers used in this study. The restriction sites are in boldface. The start and stop codons are underlined.
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Wang, N., Ni, Y. & Shi, F. Deletion of odhA or pyc improves production of γ-aminobutyric acid and its precursor l-glutamate in recombinant Corynebacterium glutamicum . Biotechnol Lett 37, 1473–1481 (2015). https://doi.org/10.1007/s10529-015-1822-4
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DOI: https://doi.org/10.1007/s10529-015-1822-4