Fermentative production of γ-aminobutyric acid (GABA) by Lactobacillus brevis using wheat bran as raw material and purification of GABA from fermentation broth were studied. Six kinds of macroporous resins and activated carbon were screened and the results indicated that resin ADS -7 had the highest decolorization ability and GABA yield. The optimal ADS -7 decolorization conditions were as follows: pH 5.0, decolorization temperature 25 ℃, decolorization
time 1 h. Under these conditions, the decolorizing efficiency was more than 95%, and the GABA yield reached up to 93%. The purification conditions of GABA by D001 cation exchange resin were optimized as follows: temperature 25 ℃, fermentation broth pH 5.0, flow rate 1 BV/h, elution with deionized water and 1 mol/L ammonia. Needle GABA crystal was obtained through concentration and crystallization, and confirmed by 1H NMR analysis.