Probiotic Properties of Lactic Acid Bacteria Isolated from Tella Produced in Adama City and Asella Town, Oromia, Ethiopia

Abstract

Probiotics are live microorganisms when taken in sufficient amounts, provide unlimited benefits to the host. Thus, this study aimed to evaluate the probiotic properties of LAB isolated from Tella produced in Adama City and Asella Town, Oromia, Ethiopia. The collected Tella samples were processed for isolation of LAB on suitable culture media following standard methods. Of 90 isolates, six LAB isolates were screened and identified as P. pentosaceus LABADI6, L. mesenteroides LABADI17, L. lactis LABADI31, L. paracasei LABASI49, L. plantarum LABASI54, and L. mesenteroides LABASI83 using MALDI-TOF-MS system. The isolates were tested for their probiotic properties, including acid and bile salt resistance, auto-aggregation, co-aggregation, hydrophobicity, antibacterial activity, antioxidant activities, and antibiotic susceptibility. The data was analyzed using spss version 27 and version 27 excel spreadsheet. Among LAB isolates, specifically L. lactis LABADI31 showed a higher degree of pH tolerance that ranged from 2 to 3 for 0, 6, and 24 h, with survival rates of 76, 66, 58, 77.6, 72.7, 66, 85, 79, and 77.3%, respectively. All the isolates survived well at lower bile salt concentrations (0.75, & 0.3% ox gal). Nevertheless, the four isolates (L. lactis LABADI31, L. paracasei LABASI49, L. plantarum LABASI54, and L. mesenteroides LABASI83) tolerated even the highest bile salt concentration content of 1.0% ox gall with the survival rate of ≥69.67 %. Among the isolates, L. lactis LABADI31 demonstrated the highest auto-aggregation with survival rates of 74.2, 85.26, and 93.23% at 0, 6, and 24 h, respectively. The co-aggregation values of the LAB isolates ranged from 44.9% (L. mesenteroides LABADI17 with P. aeruginosa ATCC 43895) at 0 h to 96.56% (L. lactis LABADI31 with E. coli ATCC 25923) at 24 h. The cell-free supernatant of the isolates exhibited antibacterial activity against foodborne pathogens of E. coli ATCC 25922, P. aeruginosa ATCC 27853, S. pyogenes ATCC 13311, and S. aureus ATCC 25923. Each isolate exhibited resistance, intermediate, and susceptibility levels to six antibiotics. Resistance was observed against two antibiotics tested, erythromycin and kanamycin. The six isolates were potentially useful in producing probiotic products for health applications. Finally, more investigation is required to assess their probiotics potential and possible in vivo effects.