Native Yeasts, Better Wines: Palm-Wine Isolates as Scalable Starters for Clean, Reproducible Fruit Fermentation

Abstract

Palm wine is a naturally fermented beverage that contains diverse yeast species important in food fermentation, with strainspecific properties influencing their applications. This study isolated and characterized yeasts from seven palm wine samples collected in Ibadan and assessed their potential in fruit wine production. A total of 101 isolates were obtained and phenotypically and biochemically characterized through sugar fermentation, urea hydrolysis, acid production, and acetic acid tolerance tests. Most isolates fermented glucose, fructose, and galactose but not maltose or mannitol. Screening for oenological properties identified strain PW10 as highly tolerant to ethanol (20%) and sugar (20%), making it suitable for watermelon must fermentation. Over a 3-day fermentation at 26–30 °C, pH declined, titratable acidity increased, specific gravity dropped from 1.055 to 1.006, and alcohol content reached 6.12%. Proximate analysis revealed significant changes in composition, microbial tests confirmed no contamination, and sensory evaluation showed good acceptability, demonstrating palm wine yeasts as promising starters for fruit wine production.