Diversity of Yeasts from Food Waste and Their Potential for Thermotolerance and Hydrolytic Enzyme Production

Abstract

The diversity of yeasts isolated from food waste at 40 °C was investigated and a total of 393 isolates were obtained. Yeasts were identifi ed using the D1/D2 domain of the large subunit (LSU) rRNA gene analysis. Only one (0.25%) basidiomycetous yeast was found, whereas the rest of the yeast isolates (99.75%) were ascomycetous. Candida tropicalis was the most prevalent species, with the highest frequency of occurrence, 86.67%, and the highest relative frequency, 26.97%. The yeast community in food waste exhibits great species diversity and evenness, as shown by the Shannon– Wiener index of 3.03 and Shannon’s Equitability index of 0.89. All yeast isolates were screened for their thermotolerance. Among 393 yeast isolates, 114 were found to be thermotolerant. Three yeasts, viz. Candida parapsilosis JS2-5, Wickerhamiella infanticola JS2-2, and C. parapsilosis JED8-65 were found to be high amylase, lipase, and protease producers on agar plates, yielding 946.97 ± 29.35 amylase U/mL, 153.93 ± 5.43 lipase U/mL, and 7.86 ± 0.02 protease U/mL under submerged cultivation at 40 °C. The overall fi ndings emphasize the species diversity of the yeast community and hydrolytic enzyme-producing capabilities within the thermotolerant yeast of food waste.