Optimisation of Fermentative Parameters for GABA Enrichment by Lactococcus lactis

Lu X.X., Xie Ch., Gu Z.X. (2009): Optimisation of fermentative parameters for GABA enrichment by Lactococcus lactis. Czech J. Food Sci., 27: 433–442. Gamma-aminobutyric acid (GABA) has antihypertensive and anti-stress functions on humans. Submerged fermentation of Lactoccocus lactis was regarded as an effective method to obtain GABA. In this study, the effects of fermentative parameters on the production of GABA was investigated. Firstly, one-variable-at-a-time experiments were performed in order to investigate the effects of significant factors influencing the GABA yield and monosodium glutamate (MSG) mole transformation percentage, i.e, the culture temperature, initial pH of the medium, MSG addition, and MSG addition time. Then, the response surface methodology (RSM) was applied to determine the optimum fermentative parameters. The results indicated that MSG addition was the most significant factor influencing GABA yield and MSG mole transformation percentage. The optimum parameters obtained by RSM for GABA enrichment by Lactoccocus lactis subsp. lactis (L. lactis) are listed as follows: temperature 31.8°C, pH 7.1 and MSG addition 15 g/l. Under these conditions, the predicted values were: GABA maximum 7.2 g/l and MSG mole transformation percentage 68.4%.