Co-production of Nisin and γ-Aminobutyric Acid by Engineered Lactococcus lactis for Potential Application in Food Preservation

Jiaheng Liu; Furong Meng; Yuhui Du; Edwina Nelson; Guangrong Zhao; Hongji Zhu; Qinggele Caiyin; Zhijun Zhang; Jianjun Qiao

doi:10.3389/fmicb.2020.00049

Co-production of Nisin and γ-Aminobutyric Acid by Engineered Lactococcus lactis for Potential Application in Food Preservation

Front Microbiol. 2020 Jan 29:11:49. doi: 10.3389/fmicb.2020.00049. eCollection 2020.

Authors

Jiaheng Liu^{1

2

3}, Furong Meng^{1

2

3}, Yuhui Du⁴, Edwina Nelson^{1

2}, Guangrong Zhao^{1

2

3}, Hongji Zhu^{1

2}, Qinggele Caiyin^{1

2}, Zhijun Zhang⁵, Jianjun Qiao^{1

2

3}

Affiliations

¹ Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, China.
² School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.
³ SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China.
⁴ Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, Beijing, China.
⁵ Key Laboratory of Storage of Agricultural Products, Ministry of Agriculture and Rural Affairs, Tianjin, China.

Abstract

Microbiological contamination and oxidative damage are the two main challenges in maintaining quality and improving shelf-life of foods. Here, we developed a Lactococcus lactis fermentation system that could simultaneously produce nisin, an antimicrobial peptide, and γ-aminobutyric acid (GABA), an antioxidant agent. In this system, we metabolically engineered a nisin producing strain L. lactis F44 for GABA production by expression of glutamate decarboxylase and glutamate/GABA antiporter. GABA biosynthesis could facilitate nisin production through enhancing acid resistance of the strain. By applying a two-stage pH-control fermentation strategy, the engineered strain yielded up to 9.12 g/L GABA, which was 2.2 times higher than that of pH-constant fermentation. Furthermore, we demonstrated the potential application of the freeze-dried fermentation product as a preservative to improve the storage performance of meat and fruit. These results suggested that the fermentation product of nisin-GABA co-producing strain could serve as a cost-effective, easily prepared, and high-performance food preservative.

Keywords: GABA; Lactococcus lactis; food preservative; metabolic engineering; nisin.