Selection and identification of antibacterial and GABA-producing lactic acid bacteria from Vietnamese fermented meat

Abstract

This study aimed to screen the lactic acid bacteria (LAB) strain that has high potential in gamma-aminobutyric acid (GABA) production and antibacterial properties, which could be applied in Vietnamese fermented meat (Nem chua) fermentation. These bacterial strains were isolated from commercial Nem chua products and stored in the laboratory. GABA synthesized from 18 strains of LAB in the MRS media adding 3% MSG was qualitative and quantitative analyzed through thin layer chromatography (TLC) and its calibration curve equation, then antibacterial activity and lactic acid production were also tested by acidic titration method, and well diffusion method, respectively. The results showed that all LAB strains synthesized GABA with a concentration from 1.323 - 1.582 mg/mL; however, eight strains were recorded with higher potential, including VL1, XP1, TP1, HC2, CP2, LV2, TX7, and HK 162. These eight strains showed the inhibition zone to Escherichia coli indicator from 4.67 - 11.67 mm. Besides, they are capable of yielding lactic acid from 18.00 - 19.35 g/L after seven days of fermentation in MRS media. The strain VL1 with the highest potential was identified as Lactobacillus plantarum. This strain was suggested as a promising starter to be applied in the Nem chua fermentation process.