초록
<P><B>Abstract</B></P> <P> <I>Phlebia</I> sp. MG-60 is a white-rot fungus that produces ethanol with high efficiency from lignocellulosic biomass without additional enzymes. Through engineering of this powerful metabolic pathway for fermentation in <I>Phlebia</I> sp. MG-60, chemical compounds other than ethanol could be produced. Here, we demonstrate sugar accumulation from unbleached hardwood kraft pulp and conversion of xylose to xylitol by pyruvate decarboxylase (<I>pdc</I>)-negative <I>Phlebia</I> sp. MG-60. We isolated <I>Phlebia</I> sp. strain MG-60-P2 from protoplasts to unify the protoplast phenotypes of the regenerated strains. Homologous recombination achieved a stable <I>pdc</I>-knockout line, designated KO77. The KO77 line produced traces of ethanol, but accumulated xylitol from xylose or glucose from unbleached hardwood kraft pulp. These metabolic changes in the <I>pdc</I>-knockout strain reflect the potential of metabolic engineering in <I>Phlebia</I> sp. MG-60 for direct production of chemical compounds from lignocellulosic biomass.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Regenerated strains from <I>Phlebia</I> sp. MG-60-P2 show the uniform phenotypes. </LI> <LI> Homologous recombination achieved a stable <I>pdc</I>-knockout line (KO77). </LI> <LI> Production of ethanol was inhibited successfully at strain KO77. </LI> <LI> KO77 accumulated xylitol from xylose or glucose from cellulose. </LI> <LI> Metabolic engineering of <I>Phlebia</I> sp. MG-60 can directly convert lignocellulose. </LI> </UL> </P>