Decoloring Technology of the Conversion Solution for Producing γ-aminobutyric Acid by Whole-cell Catalysis

Aiming at a strain of colibacillus with high-yielding γ-aminobutyric acid (GABA) in our laboratory, the whole-cell catalysis method was used to produce GABA with glutamic acid as the substrate, and the decolorization process of the conversion solution for the production of GABA was studied. In the experiment, the decolorization method of active carbon combined with resin chromatography was used. Firstly, the decolorization ability of 14 kinds of decolorizing resins was screened. The results showed that the decolorization effect of FPA53 anion-exchange resin was significantly better than that of other resins. Through the single factor test, the decolorization temperature and pH of the resin were optimized, and the ideal decolorization condition of FPA53 resin was similar to the initial condition of the conversion solution, with a temperature of 40℃ and a pH of 6. Under these conditions, the decolorization rate of the conversion liquid reached over 85.1%, the recovery rate of GABA reached over 98%, and the removal rate of glutamic acid reached over 23%. The six kinds of activated carbons were screened, and the results showed that the decolorization effect of No.2 Zhuqing activated carbon was significantly better than that of other activated carbons. The appending proportion of activated carbon was optimized through the single factor experiment, and the appending proportion of 1% activated carbon was the ideal proportion of the test. Under these conditions, the decolorization rate of the conversion solution reached over 92.8%, the recovery rate of GABA reached 99%, and the liquid loss ratio was only 2%. Finally, the selected activated carbon was combined with the decolorizing resin, and the results showed that the decolorization rate of the conversion solution after the combined use could reach over 99.5%, the recovery rate of GABA could reach over 98%, and the crystalline particles were white and no variedness. The results of this study provided a basis for GABA refining and its large-scale industrial production.