Characterisation of thermotolerant, ethanol tolerant fermentative Saccharomyces cerevisiae for ethanol production

Of the four thermotolerant, osmotolerant, flocculating yeasts (VS1, VS2, VS 3 and VS4) isolated from the soil samples collected within the hot regions of Kothagudem Thermal Power Plant, located in Khammam Dt., Andhra Pradesh, India, VSI and VS, were observed as better performers. They were identified as Saccharomyces cerevisiae. VS, and VS3 were tested for their growth char acteristics and fermentation abilities on various carbon sources including molasses at 30 degrees C and 40 degrees C respectively. More biomass and fe rmentation was observed in sucrose, fructose and glucose. Maximum amount of ethanol produced by VS3 containing 150 (g/l) of these substrates were 74, 73, and 72 (g/l) at 30 degrees C and 64, 61 and 63 (g/l) at 40 degrees C re spectively. With molasses containing 14% sugar, the amount of ethanol produ ced by VS3 was 53.2 and 45 (g/l) at 30 degrees C and 40 degrees C respectiv ely. VS3 strain showed 12% W/V ethanol tolerance. VS3 strain was also chara cterised for its ethanol producing ability using various starchy substrates in solid state and submerged fermentation: More ethanol was produced in su bmerged than solid state fermentation.