Molecular Identification of Yeast Strains with High Fermentation Capacity Isolated from Kırkağaç Melon Varieties

The yield of fermentation process, bioethanol, is one of the important product obtained from renewable energy sources. Yeasts are commonly used in ethanol production due to their high ethanol tolerance, high ethanol productivity, and their ability to ferment different kinds of simple sugars. Saccharomyces cerevisiae yeast species is the most commonly used in industrial ethanol production. Therefore, isolation and identification of new yeast strains with high fermentation capacity is very important for the bioethanol industry. The aim of this study was isolation of novel and industrially applicable yeast species that can be used in bioethanol production. Yeast strains were isolated from the Dalaman, Altınbaş and Kıvırcık sarı dilim melon varieties that are unique to Kırkağaç district of Manisa province. The fermentation ability of yeast strains was evaluated and the selected yeast strains were identified by PCR-RFLP analysis of 26S and ITS1-5.8S-ITS2 rDNA gene regions. Sequence analysis of the 26S rDNA-D1/D2 gene region was used for molecular identification of yeast strains. The phylogenetic analysis of identified yeast strains was carried out using the MEGA XI phylogenetic analysis tool. It was determined that 14 of the 53 yeast strains isolated were able to ferment glucose and sucrose, and four of them were able to ferment lactose. The yeast strains having the fermentation capacity were identified as Pichia kluyverii, Lachancea thermotolerans, Pichia kudriavzevii, Saccharomyces cf. cerevisiae/paradoxus and Saccharomyces cerevisiae. These yeast strains have the potential to be used in the bioethanol industry after other physiological and biochemical tests are complete