Interest in sustainable energy sources and bio-fuels has increased significantly in recent years. Amongst those, ethanol is one of the main substitutes considered as an alternate fuel to the oil based fuels of today, especially in the context of transportation. This clear, colorless, biodegradable, non-toxic liquid can be used in regular gasoline and diesel engines as an additive or in modified engines in its pure form, reducing emission parameters. Ethanol can be produced biologically by fermentation of various sugars found in biomass, and yeasts are the most well-established ethanol producing microorganisms. Yeast strains currently in use by the bio-ethanol industry mainly utilize glucose from sugar cane molasses (in Brazil) or the breakdown product of starch acquired from corn (in the U.S.A) or wheat (Europe). Here we depict the isolation and characterization of novel fermenting yeasts from different habitats and the evaluation of these isolates' ethanol production traits (resistance to, and production of, ethanol as well as utilization of alternative sugars). We are also investigating the effect of different plant extracts, known from previous works to be influential on metabolism and sugar uptake, in order to find potential fermentation enhancers to improve production efficiency. To date, 34 isolates from 15 habitats were tested, out of them, 18 demonstrated preferable properties in comparison to industrial strains (better ethanol resistance, higher ethanol yield, growth on pentoses). Of the three plant extracts tested, two enhanced yeast growth and ethanol production.
