GABA is a non-protein amino acid with extensive applications in functional foods and fermented products due to its physiological regulatory functions. While microbial fermentation is a preferred production method for its safety and mild conditions, natural lactic acid bacteria often suffer from low biosynthetic capacity and poor tolerance to high substrate concentrations. To address these industrial bottlenecks, a research team utilized Enterococcus faecalis as a chassis organism to develop a high-efficiency GABA production system.
The study employed a multi-step strain improvement strategy. Initially, the researchers applied ARTP mutagenesis combined with gradient resistance screening. This process yielded a mutant strain, En1203, which exhibited a GABA production increase of over 100% compared to the parental strain. To further enhance the strain's tolerance to high concentrations of monosodium glutamate (MSG), the team implemented an adaptive evolution strategy using a MMC system. This rigorous selection process resulted in the isolation of strain EM05, a genetically stable mutant under high substrate loading.
Beyond strain engineering, the researchers systematically optimized the fermentation medium. Key adjustments included the use of a mixed substrate of L-glutamic acid and MSG. In shake-flask fermentation, these optimizations allowed strain EM05 to reach a GABA concentration of 60.7 g/L. These findings demonstrate that the integration of ARTP mutagenesis, adaptive evolution, and medium optimization provides a robust framework for enhancing GABA production.
The work entitled “Enhancing γ-aminobutyric acid production by Enterococcus faecalis through atmospheric and room temperature plasma mutagenesis, adaptive evolution, and systematic fermentation optimization” was published on Systems Microbiology and Biomanufacturing (published on April 13, 2026).
DOI：10.1007/s43393-026-00464-6