Inherited loss-of-function mutations in the Rim15p-mediated stress-response pathway contribute to the high fermentation rate of sake yeast strains. In the present study, we found that disruption of the RIM15 gene in ethanol-producing Saccharomyces cerevisiae strain PE-2 accelerated molasses fermentation through enhanced sucrose utilization following glucose starvation. (C) 2013, The Society for Biotechnology, Japan. All rights reserved.