Enhancement of γ-Amminobutyric Acid Production by Co-Culturing of Two Lactobacilli Strains

Abstract

The γ-Amino Butyric Acid (GABA) is a major inhibitory neurotransmitter in central nervous system and its application in drugs and functional foods has attracted great attention. Most of the fermented food products are known and proven for its high content GABA producer, which makes the food product as potential functional foods. Lactic acid bacteria possess special physiological activities and are generally regarded as safe. This study was aimed at evaluating GABA production ability of some lactic acid bacteria strains isolated from Egyptian dairy products and further to increase the production by combining the best GABA producers. The impacts of pH, temperature, incubation time, initial monosodium glutamate (MSG) concentration and pyridoxal-5'-phosphate (PLP) addition on growth and γ-aminobutyric acid production were investigated. By optimizing these factors at pH5, cultivation temperature of 35°C, cultivation time of 72 h in medium supplemented with 750 M of MSG and 200 μM of PLP, Lactobacillus brevis NM101-1 and Lactobacillus plantarum DSM749 accumulated 168.58 and 140.69 mM of GABA, respectively. Co-culturing of both strains was not only able to enhance GABA production but also producing it in a short time (48 h), reached 224.69 mM. It could be concluded that the use of LAB strains in combination with a high GABA producer strain is a successful approach for reaching a physiologically active concentration of GABA.