초록
<P><B>Background</B></P><P>Bioethanol obtained by fermenting cellulosic fraction of biomass holds promise for blending in petroleum. Cellulose hydrolysis yields glucose while hemicellulose hydrolysis predominantly yields xylose. Economic feasibility of bioethanol depends on complete utilization of biomass carbohydrates and an efficient co-fermenting organism is a prerequisite. While hexose fermentation capability of <I>Saccharomyces cerevisiae</I> is a boon, however, its inability to ferment pentose is a setback.</P><P><B>Results</B></P><P>Two xylose fermenting <I>Kodamaea ohmeri</I> strains were isolated from <I>Lagenaria siceraria</I> flowers through enrichment on xylose. They showed 61% glucose fermentation efficiency in fortified medium. Medium engineering with 0.1% yeast extract and peptone, stimulated co-fermentation potential of both strains yielding maximum ethanol 0.25 g g<SUP>−1</SUP> on mixed sugars with ~ 50% fermentation efficiency. Strains were tolerant to inhibitors like 5-hydroxymethyl furfural, furfural and acetic acid. Both <I>K. ohmeri</I> strains grew well on biologically pretreated rice straw hydrolysates and produced ethanol.</P><P><B>Conclusions</B></P><P>This is the first report of native <I>Kodamaea</I> sp. exhibiting notable mixed substrate utilization and ethanol fermentation. <I>K. ohmeri</I> strains showed relevant traits like utilizing and co-fermenting mixed sugars, exhibiting excellent growth, inhibitor tolerance, and ethanol production on rice straw hydrolysates.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (10.1186/s13065-018-0375-8) contains supplementary material, which is available to authorized users.</P>