Widespread effect of N-acetyl-d-glucosamine assimilation on the metabolisms of amino acids, purines, and pyrimidines in Scheffersomyces stipitis

Abstract

BackgroundFollowing cellulose, chitin is the most abundant renewable resource and is composed of the monomeric amino sugar N-acetyl-d-glucosamine (GlcNAc). Although many yeasts, including Saccharomyces cerevisiae, have lost their ability to utilize GlcNAc, some yeasts are able to use GlcNAc as a carbon source. However, our understanding of the effects of GlcNAc on the intracellular metabolism of nitrogen-containing compounds in these yeast species is limited.ResultsIn the present study, we quantitatively investigated the metabolic responses to GlcNAc in the GlcNAc-assimilating yeast Scheffersomyces stipitis (formerly known as Pichia stipitis) using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). The comprehensive analysis of the metabolites extracted from S. stipitis cells grown in glucose, xylose, or GlcNAc revealed increased intracellular accumulation of a wide range of nitrogen-containing compounds during GlcNAc assimilation in this yeast. The levels of aromatic, branched-chain, and sulfur-containing amino acids and adenine, guanine, and cytosine nucleotides were the highest in GlcNAc-grown cells.ConclusionsThe CE-TOFMS analysis revealed a positive effect for GlcNAc on the intracellular concentration of a wide range of nitrogen-containing compounds. The metabolomic data gathered in this study will be useful for designing effective genetic engineering strategies to develop novel S. stipitis strains for the production of valuable nitrogen-containing compounds from GlcNAc.