Biotechnological Potential of Lactic Acid Bacteria Isolated From Ethiopian Honey Wine, <i>Tej</i>

Some members of the lactic acid bacteria (LAB) have been used as probiotics. Ethiopian honey wine, <i>Tej</i>, may be a useful source of potential probiotic bacteria. However, LABs from this source have not yet been evaluated for their probiotic properties. This study was conducted to evaluate the <i>in vitro</i> probiotic properties of LAB isolated from Ethiopian honey wine, <i>Tej</i>. For this purpose, 30 samples were collected from Southwest Ethiopia. LAB isolates were first tested for their antimicrobial activity and those with this property were evaluated for probiotic properties, such as tolerance to acid, salt, and bile, adherence properties, anticholesterol activity, antioxidant activity, and antibiotic susceptibility. The antibacterial activity of the LAB isolates against test organisms was assessed by the agar well diffusion method. Acid, salt, and bile tolerance were evaluated by the plate count method. Adhesion properties were assessed by the determination of bacterial hydrophobicity to the nonpolar solvent p-xylene. Anticholesterol was determined by measuring the remaining cholesterol in the spent broth. The antioxidant capacity was assessed by the 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging capacity, and the antibiotic susceptibility of isolates was tested by the disk diffusion method. A total of 143 LABs were isolated from <i>Tej</i> samples. The LAB count was ranged between 7.4 and 6.5 log cfu/mL. Of the 143 LAB isolates, 37 exhibited different levels of antimicrobial activity. Eight of these were identified to species level by 16S ribosomal genes sequence analysis. The greatest inhibition was against <i>Shigella boydii</i> ATCC 25931 with 19 ± 4.2 mm, and the least inhibitory activity was against <i>Escherichia coli</i> ATTC 25922 and <i>Staphylococcus aureus</i> ATTC 25913 with 8.0 ± 1.4. All except two isolates survived at pH 2 and pH 3 (18.4%-89.6%). Then, 37 isolates survived in more than 50% bile and 54%-67% adhesion capacity. The cholesterol-lowering and 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging capacities ranged from 8% to 54% and 13% to 33%, respectively. Most isolates were susceptible to antibiotics, except for one isolate that resisted all tested antibiotics. This study shows that many LABs isolated from Ethiopian honey wine, <i>Tej</i> have probiotic properties and they can be considered as probiotic candidates. We recommend evaluation of <i>in vivo</i> probiotic properties of the LAB isolates to provide strong supporting evidence.