Abstract
Aim: Palm wine and burukutu are indigenous fermented beverages that serve as a rich source of microorganisms with probiotic potentials, which may proffer many health benefits when consumed. Hence, this study was designed to isolate and characterize yeast and bacteria with probiotic potential from indigenous fermented beverages.
Methods: Yeasts and lactic acid bacteria were isolated from locally sourced palm wine, burukutu, and milk using YEA and MRS media, respectively. The potential probiotic properties of the yeast and bacterial isolates were evaluated following their ability to grow at an elevated temperature, tolerate high osmotic pressure (NaCl), and survive at low pH. Safety assessment of yeast isolates was carried out based on DNase production and hemolytic activities following standard microbiological methods. Molecular characterization of the best-performing yeast isolate was carried out using the highly conserved D1/D2 domain of the 26S rDNA.
Results: A total of ten (10) yeast and four (4) bacteria were isolated, and biochemical characteristics showed that the yeast isolates belonged to the genera Saccharomyces and Pichia, while the bacterial isolates belonged to the genus Lactobacillus. All the isolates could grow at 37±2 oC. The highest salt (NaCl) tolerance concentration for both the yeast and bacterial isolates was 12% and 9%, respectively. The survivability of yeasts and bacterial isolates at pH 2.5 after 2 hrs showed that one yeast strain (PWY4) had vigorous growth after 24 hrs of incubation, while the growth rate of the bacterial isolates was moderate to slow. The best-performing yeast strain was further identified as Saccharomyces cerevisiae AZ71, and the safety assessment of the strain showed that it was negative for both DNase production and hemolytic activity.
Conclusion: Saccharomyces cerevisiae AZ71, isolated from indigenous fermented beverages, demonstrated strong tolerance to heat, acid, and salt, alongside the absence of DNase and hemolytic activity. This provides preliminary evidence that indicates its safe probiotic potential and supports traditional palm wine and burukutu as valuable sources of functional microorganisms.

Key words: Probiotics, yeast, lactic acid bacteria, probiotic potentials.