Development of an integrated process for the production of high-purity γ-aminobutyric acid from fermentation broth

γ-Aminobutyric acid (GABA), a natural non-protein amino acid, plays an irreplaceable role in regulating the life activities of organisms. Nowadays, the separation and purification of food-grade GABA from fermentation broth is still a great challenge. This research utilized monosodium glutamate as a substrate for the production of high-purity GABA via an integrated process incorporating fermentation, purification, and crystallization. Firstly, 147 g·L−1 GABA with a yield of 99.8% was achieved through fed-batch fermentation by Lactobacillus brevis CE701. Secondly, three integrated purification methods by ethanol precipitation were compared, and crude GABA with a purity of 89.85% was obtained by the optimized method. Thirdly, GABA crystals with a purity of 98.69% and a yield of 60% were further obtained through a designed crystallization process. Furthermore, the GABA industrial production process model was established by Superproper Designer V10 software, and material balance and economic analysis were carried out. Ethanol used in the process was recovered with a recovery of 98.79% through Aspen simulated extractive distillation. Then the fixed investment (equipment purchase and installation costs) for an annual production of 80 t GABA will be about 833000 USD; the total annual production cost (raw material cost and utility cost) will be about 641000 USD. The annual sale of GABA may be at the range of 2400000–4000000 USD and the payback period will be about 1–2 year. This integrated process provides a potential way for the industrial-scale production of food-grade GABA.