BACKGROUND AND OBJECTIVE: Gamma-aminobutyric acid (GABA) is a non-protein amino acid that can be found broadly in all organisms. GABA is synthesized by glutamate decarboxylase (GAD). Therefore, GABA production depends on biochemical properties of this enzyme. GABA has several physiological functions such as hypotensive activity, insomnia, depression, as well as diuretic effects. Bacteria, fungi and yeast produce considerable amount of GABA. Among bacteria, acid lactic bacteria due to their physiological and safety properties have been considered. These bacteria are used in food industry and act as probiotics in digestive system. The aim of this study was to identify and introduce GABA producing acid lactic bacteria.

METHODS: In this paper using data banks such as PubMed and Google scholar and key words such as GABA producing acid lactic bacteria, isolation sources of them, factors that affect GABA production, acid lactic bacteria glutamate decarboxylase properties, glutamate decarboxylase gene cloning and regulation of them, the potential applications of GABA producing acid lactic bacteria and strain screenings have been reviewed.

FINDINGS: Data from variety of papers showed that production of GABA using acid lactic bacteria is safe and biocompatible. This may lead to GABA rich fermented products.

CONCLUSION: Results of this study showed that natural GABA has significant effects on human health. Therefore it seems acid lactic bacteria are the most suitable sources for GABA production.