Extraction and identification of probiotic bacteria with potential of GABA production from traditional West Azarbaijan diary of Iran

Abstract

Lactic acid bacteria play a critical role in fermentation courses. One of the metabolites produced by this bacterial strain is Gamma Amino Butyric Acid (GABA). The objective of this research was extraction and identification of probiotic bacteria with potential of GABA production from traditional West Azarbaijan dairy of Iran and optimization of GABA production conditions in culture. In this study, 30 bacterial samples from indigenous dairy products (yogurt, dough, cheese and butter) were isolated from West Azarbaijan of Iran. Initial diagnostic tests including gram stain, oxidase and catalase tests were performed to detect Lactic Acid Bacteria (LAB). Results showed that only 6 strains were gram-positive, negative catalase and negative oxidase, and were known as LAB. Then, investigation of probiotic properties including acid resistance, bile, gastric juice, and hemolysis inactivity and L- arginine hydrolysis were evaluated. Two LAB samples with strong probiotic properties were selected, followed by identification of the primers with 16SrDNA by sequencing and drawing phylogeny tree. The results showed that L. lactis subspecies Lactis, L. delbrucius subspecies Bulgaricus strains isolated from cheese and butter had the highest probiotic properties. In the second part, the concentration of GABA production by probiotic bacteria was evaluated by HPLC in media of MRS Broth. Based on HPLC results, L. delbrucius subspecies Bulgaricus, grown in MRS broth had shown the highest concentration of GABA production with 377.54 ppm.