Isolation, identification and potential probiotic characterization of lactic acid bacteria from Thai traditional fermented food

Abstract

<abstract> <p>The probiotic potential of lactic acid bacteria (LAB) isolated from Thai traditional fermented food was investigated. Forty-two samples were collected from four markets in Phra Nakhon Si Ayutthaya Province. Out of 50 isolated LAB, 6 (a3, f4, f8, K1, K4 and K9) obtained from pla-ra and bamboo shoot pickle samples showed high tolerance to gastrointestinal tract conditions. These isolates were selected to identify and characterize their probiotic properties. Isolate a3 was identified as <italic>Weissella thailandensis</italic>, isolates f4 and f8 were identified as belonging to <italic>Enterococcus thailandicus</italic> and isolates K1, K4 and K9 were determined as <italic>Limosilactobacillus fermentum</italic>. All six LAB exhibited high autoaggregation ability (93.40–95.01%), while <italic>W. thailandensis</italic> isolate a3 showed potential for coaggregation in almost all the pathogenic bacteria tested. Cell-free supernatant (CFS) obtained from all isolates did not inhibit <italic>Staphylococcus aureus</italic>. CFS derived from <italic>L. fermentum</italic> isolate K4 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria, while <italic>L. fermentum</italic> isolate K4 presented high surface hydrophobicity in the presence of xylene and n-hexane. All LAB isolates were found to be resistant to clindamycin and nalidixic acid, whereas <italic>E. thailandicus</italic> isolate f8 exhibited resistance to most of the antibiotics tested. <italic>L. fermentum</italic> isolate K4 showed promise as a suitable probiotic candidate for future applications in the food industry due to tolerance to gastrointestinal tract conditions with high surface hydrophobicity and inhibited most of the pathogens tested.</p> </abstract>