Title : Evaluation of the probiotic properties of lactic acid bacteria isolated from ethiopian honey wine (‘Tej’)
Abstract:
Ethiopian honey wine (‘Tej’) is a popular and widely consumed local beverage. ‘‘Tej’’ is known to pose health problems such as toxicity due to the high alcoholic content, undesirable additives, and hazardous metabolites. Lactic acid bacteria (LAB) and yeasts have been frequently identified from ‘Tej’, however, the impact of which on human health is not yet understood. Therefore, it is essential to identify and investigate the health impact of probiotics properties of LAB. The aim of this research is to identify and investigate the probiotic properties of LAB from ‘Tej’ samples.
Material and methods: ‘Tej’ samples were collected from Addis Ababa and LABs were identified following morphological, physiological, and biochemical analysis. The probiotic properties of identified LAB were determined following a basic property assay starting with low pH tolerance. Subsequently, the safety of a probiotic LAB was assessed based on its antibiotic susceptibility and haemolysis properties. Finally, MALDI-TOF MS was used to identify species of probiotic LAB and results were presented as mean ± standard deviations (SD).
Result: A total of 280 LABs were identified from 53 ‘Tej’ samples. The 54% and 46 % of the isolates were found to be rod and coccoid-shaped, respectively. Based on the morphological, biochemical, and physiological results, the isolates were temporarily grouped into five genera. These were Lactobacillus, Lactococcus, Leuconostocs, Enterococcus, and Streptococcus. The pH tolerance at pH 2.0 and 3.0 was found to be in the range of 23.0 - 84.6% and 17.9 - 72.7%, respectively. The LAB isolates tolerant to 0.3% were found to be in the range of 21.8±0.02 % to 92.5±0.03 % survival rate, respectively. Consequently, LAB isolates showed microbial cell adhesion to hydrocarbons with a range of 11.2 - 77.9% considered for the radical scavenging activity test and their cholesterol-lowering ability. Most LAB isolates were sensitive to six to eight antibiotics. The 36.7 % of probiotic LAB isolates exhibit non-haemolytic activity. All of the Non-haemolytic and antibiotic-sensitive probiotic LABs are lactobacillus from which Levilactobacillus paracasei is the most dominant probiotic LAB species while Levilactobacillus parabuchneri is the least dominant probiotic LAB species.
Conclusion: among the identified 280 LABs; 34 isolates revealed potential probiotic properties under in vitro experimental conditions and will be further tested for in-vivo probiotic assays in the future.
Keywords: Lactic acid bacteria, probiotic properties, ‘Tej’, MALDI-TOF MS
