Enhancing High-Level Food-Grade Expression of Glutamate Decarboxylase and Its Application in the Production of γ-Aminobutyric Acid
Year: 2024
Type: article
Abstract: Gamma-aminobutyric acid (GABA), a non-proteinogenic amino acid, exhibits diverse physiological functions and finds extensive applications in food, medicine, and various industries.Glutamate decarboxylase (GAD) can effectively convert L-glutamic acid (L-Glu) or monosodium glutamate (MSG) into GABA.However, the low food-grade expression of GAD has hindered large-scale GABA production.In this study, we aimed to elevate GAD expression in Bacillus subtilis through cofactor synthesis enhancement, CRISPRi-based host strain modification, and fermentation optimization.In a 3-L fermenter, the optimized strain achieved a remarkable GAD activity of 319.62 U/ml without antibiotic selection pressure, representing the highest reported food-grade expression to date.Subsequently, enzymatic property analysis facilitated the optimization of GABA production using MSG and L-Glu as substrates, achieving 100% molar conversion yields of 274.40 g/l and 481.62 g/l, respectively, with the latter yielding an unprecedented productivity of 48.16 g/l/h.Finally, in vitro fermentation demonstrated that GABA supplementation promoted gut microbial growth and increased the relative abundance of Actinobacteriota and Bacteroidota.
Institution: Jiangnan University
Language: English
Topic: GABA and Rice Research
Subfield: Plant Science
Domain: Life Sciences
Open Access status: bronze
Awards: G2132924444, G3504941352, G7173455368
OpenAlex ID: W4406807740