Medium optimization for γ-aminobutyric acid production by response surface methodology

Abstract

In this work, the fermentation medium for γ-Aminobutyric acid (GABA) production by Enterococcus raffinosus TCCC11660 in shaken flasks was studied by the Plackett-Burman design. In the preliminary single-factor experiments, sucrose, pyridoxal 5′-phosphate (PLP) and glycine were found to have significant effects on GABA production at the suitable concentration ranges. Subsequently, the screened factors were optimized using Box-Behnken design of response surface methodology. The results showed that the optimal key medium compositions for GABA production by E. raffinosus TCCC11660 were 8.9 g/L citric acid, 0.82 g/L glycine and 0.21 mmol/L PLP, respectively. By fermentation medium optimization, GABA production reached 77.5 g/L, which was enhanced by 103.9% compared to the initial medium.