Separation and purification of Gamma-aminobutyric acid fermentation broth by ultrafiltration

By selecting and optimising lactic acid bacteria, maximum amount of gamma-aminobutyric acid (GABA) in fermentation broth can reach 0.54 g/100 ml, which is very low. Ultrafiltration (UF) process can effectively separate and purify GABA fermentation broth, so as to increase the GABA content. After pre-treatment with high speed centrifugation, the optimal operation pressure and circulation velocity of UF process are obtained according to the testing result of flux and the observation of membrane under scanning electron microscopy (SEM). Under the optimal operation pressure and circulation velocity, the optimal concentration rate is studied, considering the performance of UF process and the request of GABA recycle rate. Under the optimal operation pressure, the optimal circulation velocity and the optimal concentration rate, after high speed centrifugation and UF 64% of the protein can be retained. The purity of GABA will be increased to 6.2 g/100 ml and recycle rate increased to 88.6%.