The maximum ethanol concentration produced from glucose in defined media at 45°C by the thermotolerant yeast Kluyveromyces marxianus IMB3 was 44 g L−1. Acclimatisation of the strain through continuous culture at ethanol concentrations up to 80 g L−1, shifted the maximum ethanol concentration at which growth was observed from 40 g L−1 to 70 g L−1. Four isolates were selected from the continuous culture, only one of which produced a significant increase in final ethanol concentration (50 ± 0.4 g L−1), however in subsequent fermentations, following storage on nutrient agar plates, the maximum ethanol concentration was comparable with the original isolate. The maximum specific ethanol production rates (approximately 1.5 g (gh)−1) were also comparable with the original strain except for one isolate (0.7 g (gh)−1). The specific ethanol productivity decreased with ethanol concentration; this decrease correlated linearly (rval 0.92) with cell viability. Due to the transience of induced ethanol tolerance in the strain it was concluded that this was not a valid method for improving final ethanol concentrations or production rates.
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Received 18 July 1997/ Accepted in revised form 19 February 1998
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Hack, C., Marchant, R. Ethanol adaptation in a thermotolerant yeast strain Kluyveromyces marxianus IMB3. J Ind Microbiol Biotech 20, 227–231 (1998). https://doi.org/10.1038/sj.jim.2900511
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DOI: https://doi.org/10.1038/sj.jim.2900511