ISOLATION OF THERMOTOLERANT, FERMENTATIVE YEASTS GROWING AT 52-DEGREES-C AND PRODUCING ETHANOL AT 45-DEGREES-C AND 50-DEGREES-C

Five thermotolerant, alcohol-producing yeast cultures were isolated from samples obtained from India. Two were identified as of Kluyveromyces marxianus. All five grew on plate-cultures up to 52-degrees-C, with maximum growth rates in liquid culture at 40-degrees-C. All produced relatively high alcohol concentrations: 5.7 to 7.0% (w/v) at 45-degrees-C and 5.0 to 5.5% (w/v) at 50-degrees-C when growing on 14.0% (w/v) glucose. All five isolates fermented diluted molasses containing 16.0% (w/v) total sugars, producing 5.6 to 6.0% (w/v) alcohol concentrations. Supplementing the molasses with P, K, Mg and Mn resulted in a 13 to 20% increase in alcohol production at 40-degrees-C. The maximum amounts of alcohol produced on supplemented molasses were 7.5 to 8.0 and 6.5 to 7.0% (w/v) at 37-degrees-C and 40-degrees-C, respectively.