Isolation and characterization of osmophilic fermentative yeasts from Bangladeshi honeys

Despite the medicinal values and economic importance, honey is also a source of osmophilic fermentative yeasts. So, it can be utilized for the isolation of local fermentative yeast. Here, 1 ml honey was inoculated in YPD (Yeast extract peptone dextrose) broth containing 4% dextrose. After overnight incubation, the broth was streaked on an YPD agar plate to purify yeast colonies. In this study, total eight strains were isolated from seven physio-chemically defined florally diversified honey samples of Bangladesh. Microscopic morphology, plasmid profile, growth pattern and fermentative capacity of these isolates were determined. Under light microscope, these yeasts had one of three distinct shapes: ovoid, spherical, or cylindrical. The cytoplasm in young, actively reproducing cells occupied most of the interior and looked homogeneous. Two plasmids of around 3kb and 2.1 kb were common in these strains except for one. While compared with Baker’s yeast, these strains showed faster growth. Five of them were attributed to high fermentative potency. Yeast 2 showed the highest fermentative potency yielding 33.48% (v/v) ethanol. We suggest that these strains have potentialities for efficient bioethanol production to meet the increasing demand of biofuel.