The simultaneous sacchari®cation and fermentation was used to produce ethanol from raw starch of damaged quality wheat and sorghum grains by utilising crude amylase preparation from B. subtilis VB2 and an amylolytic yeast strain S. cerevisiae VSJ4. Various concentrations of damaged wheat and sorghum starch from 10% to 30%W/V were used and 25% was found to be optimum for damaged wheat and sorghum starch yielding 4.40%V/V and 3.50%V/V ethanol respectively. Whereas 25% raw starch of ®ne quality wheat and sorghum grains gave an yield of 5.60%V/V and 5.00%V/V respectively. The process was carried out at 35°C, 5.8 pH and 200 rpm for 4 days.

Of the four thermotolerant, osmotolerant, occulating yeasts (VS 1 , VS 2 , VS 3 and VS 4 ) isolated from the soil samples collected within the hot regions of Kothagudem Thermal Power Plant, located in Khammam Dt., Andhra Pradesh, India, VS 1 and VS 3 were observed as better performers. They were identi®ed as Saccharomyces cerevisiae. VS 1 and VS 3 were tested for their growth characteristics and fermentation abilities on various carbon sources including molasses at 30°C and 40°C respectively. More biomass and fermentation was observed in sucrose, fructose and glucose. Maximum amount of ethanol produced by VS 3 containing 150 (g/l) of these substrates were 74, 73, and 72 (g/l) at 30°C and 64, 61 and 63 (g/l) at 40°C respectively. With molasses containing 14% sugar, the amount of ethanol produced by VS 3 was 53.2 and 45 (g/l) at 30°C and 40°C respectively. VS 3 strain showed 12% W/V ethanol tolerance. VS 3 strain was also characterised for its ethanol producing ability using various starchy substrates in solid state and submerged fermentation. More ethanol was produced in submerged than solid state fermentation.