The use of a thermotolerant fermentative <i>Kluyveromyces marxianus</i> IMB3 yeast strain for ethanol production

Abstract

Abstract An investigation was carried out on the growth and ethanol production of a novel thermotolerant ethanol‐producing Kluyveromyces marxianus IMB3 yeast strain. It grew aerobically on glucose, lactose, cellobiose, xylose and whey permeate and fermentad all the above carbon sources to ethanol at 45°C. This strain was capable of growing under anaerobic chemostat fermentation conditions at 45°C and a dilution rate of 0.15 h −1 and produced ≤ 0.9 g/l biomass and 1.8% (v/v) ethanol. An increase in biomass (up to 10.0 g/l) and ethanol (up to 4.3% v/v at 45°C and 7.7% v/v at 40°C) were achieved by applying a continuous two‐stage fermentation in sequence (one aerobic and one anaerobic stage) or a two‐stage anaerobic fermentation with cell recycling. Potential applications, involving alcohol production systems, for use in dairy and wood related industries, were discussed.