Abstract:

In this study, we optimized medium components and culture conditions of Candida sp. Y6, a γ-aminobutyric
acid (GABA)-producing strain isolated from the surface of pitaya, using response surface methodology (RSM). The
content of GABA in fermentation broth was analyzed by reversed phase high performance chromatography (RP-HPLC).
The optimal fermentation medium was found to consist of 23 g/L sucrose, 65 g/L wheat bran, 6 g/L L-glutamate, and 0.5 mmol/L
pyridoxal phosphate, and the optimal culture conditions were initial medium pH 4.5 and 28 ℃ for 3.5 d with a shaking speed of
200 r/min. Under the optimal conditions, the yield of GABA was increased 72% when compared with that before optimization.

Key words: γ-aminobutyric acid, Candida sp., response surface methodology, medium components