Method for producing gamma-aminobutyric acid

The invention discloses a method for producing gamma-aminobutyric acid, which comprises the following steps of: (a) treating soybean milk with protease to obtain enzymatic soybean milk; (b) inoculating Lactobacillus plantarum (CGMCC (China General Microbiological Culture Collection Center) No. 1.557) to a fermentation culture medium, and keeping stand and culturing at the temperature of 20 to 50 DEG C for 30-60h to obtain gamma-aminobutyric acid. The preparation method of the fermentation culture medium comprises the following steps that: 10-40g of glucose, 10-40g of peptone, 10-40g of sodium glutamate, and 0.001-0.004g of pyridoxal hydrochloride are taken to be dissolved in the enzymatic soybean milk and be dilute to 1L. According to the method provided by the invention, the enzymatic soybean milk is creatively used as a solvent of the fermentation culture medium (a nitrogen source is provided at the same time), so that the yield of the gamma-aminobutyric acid can be greatly improved. The method lays a theor