Isolation and characterization of ethanol-producing yeasts from fruits and tree barks

Aims: Isolation and identification of yeasts converting xylose to ethanol. Methods and Results: A total of 374 yeasts were isolated from a variety of rotten fruits and barks of trees. Out of these, 27 yeast strains were able to assimilate xylose and produce 0.12-0.38 g of ethanol per gram of xylose. Based on phylogenetic analysis of D1/D2 domain sequence of LSU (Large Subunit) rRNA gene and phenotypic characteristics the ethanol-producing strains were identified as member(s) of the genera Pichia, Candida, Kluyveromyces, Issatchenkia, Zygosacchraomyces, Clavispora, Debaryomyces, Metschnikowia, Rhodotorula and Cryptococcus. Conclusion: Yeast strains producing ethanol from xylose have been isolated from a variety of rotten fruits and barks of trees and identified. Significance and Impact of the Study: Environmental isolates of yeasts which could convert xylose to ethanol could form the basis for bio-fuel production and proper utilization of xylan rich agricultural and forest wastes.