초록
<P><B>Background</B></P><P>As one of the best xylose utilization microorganisms, <I>Scheffersomyces stipitis</I> exhibits great potential for the efficient lignocellulosic biomass fermentation. Therefore, a comprehensive understanding of its unique physiological and metabolic characteristics is required to further improve its performance on cellulosic ethanol production.</P><P><B>Results</B></P><P>A constraint-based genome-scale metabolic model for <I>S. stipitis</I> CBS 6054 was developed on the basis of its genomic, transcriptomic and literature information. The model <I>i</I>TL885 consists of 885 genes, 870 metabolites, and 1240 reactions. During the reconstruction process, 36 putative sugar transporters were reannotated and the metabolisms of 7 sugars were illuminated. Essentiality study was conducted to predict essential genes on different growth media. Key factors affecting cell growth and ethanol formation were investigated by the use of constraint-based analysis. Furthermore, the uptake systems and metabolic routes of xylose were elucidated, and the optimization strategies for the overproduction of ethanol were proposed from both genetic and environmental perspectives.</P><P><B>Conclusions</B></P><P>Systems biology modelling has proven to be a powerful tool for targeting metabolic changes. Thus, this systematic investigation of the metabolism of <I>S. stipitis</I> could be used as a starting point for future experiment designs aimed at identifying the metabolic bottlenecks of this important yeast.</P>