Vol. 11, Issue 1 (2022)

Author(s):
P Jayamma, G Geeta Shirnalli, D Geeta Goudar and S Nagaratna Olekar

Abstract:
The application of high-potential thermotolerant yeasts is a key factor for successful ethanol production at high temperatures. In the present study, thermotolerant yeast strains were isolated from different fruit wastes. A total of 110 yeasts were isolated by an enrichment culture technique from different fruit wastes like sapota, papaya, mango, pineapple, banana, grapes and orange. Based on the typical colony characteristic on Yeast extract dextrose agar after 48 h of incubation, smooth, shiny, creamish colonies were picked up and purified and observed under a microscope based on the budding character, the colonies were selected. The selected isolates were screened to determine thermotolerance by growing at different temperatures viz. 35, 40 and 45 ^oC by using YPD broth. Among these, 20 isolates were capable of growing at 45 ^oC and 70 strains survived and grew at a temperature of 40 ^oC, while 30 strains could only endure a maximum of 35 ^oC. Finally, based on the results it was concluded that 20 yeast isolates grew satisfactorily at all three temperatures viz. 35, 40 and 45 ^oC.