Characterization of Autochthonous Lactic Acid Bacteria Isolated from a Traditional Ethiopian Beverage, Tella

Abstract

This study aimed to isolate lactic acid bacteria (LAB) from a traditional Ethiopian fermented product, <i>Tella</i>, and evaluate their functional properties. Of forty-three isolates, seven LAB were screened and identified as <i>Pediococcus pentosaceus</i>, <i>Latilactobacillus curvatus</i>, <i>Leuconostoc mesenteroides</i>, and <i>Lactiplantibacillus plantarum</i> species. The isolates were tested for their alcohol tolerance, acid and bile resistance, auto-aggregation, co-aggregation, hydrophobicity, antibacterial activity, and antibiotic susceptibility. LAB isolates, specifically <i>P. pentosaceus</i> TAA01, <i>L. mesenteroides</i> TDB22, and <i>L. plantarum</i> TDM41, showed a higher degree of alcohol tolerance in 8% and 10% (<i>w</i>/<i>v</i>) ethanol concentrations. Additionally, these three isolates displayed survival rates >85% in both acidic pH and bile environments. Among the isolates, <i>L. plantarum</i> TDM41 demonstrated the highest auto-aggregation, co-aggregation, and hydrophobicity with (44.9 ± 1.7)%, (41.4 ± 0.2)%, and (52.1 ± 0.1)% values, respectively. The cell-free supernatant of the isolates exhibited antibacterial activity against foodborne pathogens of <i>Escherichia coli</i>, <i>Salmonella</i> Enteritidis, and <i>Staphylococcus aureus.</i> Each isolate exhibited various levels of resistance and susceptibility to seven antibiotics and resistance was observed against four of the antibiotics tested. After performing a principal component analysis, <i>Pediococcus pentosaceus</i> TAA01, <i>L. mesenteroides</i> TDB22, and <i>L. plantarum</i> TDM41 were selected as the most promising ethanol-tolerant probiotic isolates.