Enhanced production of gamma-aminobutyrate (GABA) in recombinant Corynebacterium glutamicum by expressing glutamate decarboxylase active in expanded pH range

Microbial Cell Factories

Research

Seung Hwan Lee¹  Taek Jin Kang²  Jae Woong Choi³  Sung Sun Yim³  Ki Jun Jeong⁴  Si Jae Park⁵ 

[1] Department of Biotechnology and Bioengineering, Chonnam National University, 77 Yongbong-ro, 500-757, Buk-gu, Gwangju, Republic of Korea;Department of Chemical and Biochemical Engineering, Dongguk University-Seoul, 30 Pildong-ro 1-gil, 100-715, Jung-gu, Seoul, Republic of Korea;Department of Chemical and Biomolecular Engineering (BK21 Plus Program), KAIST, 335 Gwahagno, 305-701, Yuseong-gu, Daejeon, Republic of Korea;Department of Chemical and Biomolecular Engineering (BK21 Plus Program), KAIST, 335 Gwahagno, 305-701, Yuseong-gu, Daejeon, Republic of Korea;Institute for the BioCentury, KAIST, 335 Gwahagno, 305-701, Yuseong-gu, Daejeon, Republic of Korea;Department of Environmental Engineering and Energy, Myongji University, 116 Myongji-ro, Cheoin-gu, 449-728, Yongin, Gyeonggido, Republic of Korea;

关键词: Corynebacterium glutamicum;    Gamma-aminobutyrate;    Glutamate;    Glutamate decarboxylase;    Biotin;    Fed-batch cultivation;   

DOI  :  10.1186/s12934-015-0205-9

 received in 2014-10-13, accepted in 2015-02-05,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundGamma-aminobutylate (GABA) is an important chemical in pharmacetucal field and chemical industry. GABA has mostly been produced in lactic acid bacteria by adding L-glutamate to the culture medium since L-glutamate can be converted into GABA by inherent L-glutamate decarboxylase. Recently, GABA has gained much attention for the application as a major building block for the synthesis of 2-pyrrolidone and biodegradable polyamide nylon 4, which opens its application area in the industrial biotechnology. Therefore, Corynebacterium glutamicum, the major L-glutamate producing microorganism, has been engineered to achieve direct fermentative production of GABA from glucose, but their productivity was rather low.ResultsRecombinant C. glutamicum strains were developed for enhanced production of GABA from glucose by expressing Escherichia coli glutamate decarboxylase (GAD) mutant, which is active in expanded pH range. Synthetic PH36, PI16, and PL26 promoters, which have different promoter strengths in C. glutamicum, were examined for the expression of E. coli GAD mutant. C. glutamicum expressing E. coli GAD mutant under the strong PH36 promoter could produce GABA to the concentration of 5.89 ± 0.35 g/L in GP1 medium at pH 7.0, which is 17-fold higher than that obtained by C. glutamicum expressing wild-type E. coli GAD in the same condition (0.34 ± 0.26 g/L). Fed-bath culture of C. glutamicum expressing E. coli GAD mutant in GP1 medium containing 50 μg/L of biotin at pH 6, culture condition of which was optimized in flask cultures, resulted in the highest GABA concentration of 38.6 ± 0.85 g/L with the productivity of 0.536 g/L/h.ConclusionRecombinant C. glutamicum strains developed in this study should be useful for the direct fermentative production of GABA from glucose, which allows us to achieve enhanced production of GABA suitable for its application area in the industrial biotechnology.

【 授权许可】

Unknown   
© Choi et al.; licensee BioMed Central. 2015. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.