Xylan represents a major component of lignocellulosic biomass, and its utilization by Saccharomyces cerevisiae is crucial for the cost effective production of ethanol from plant biomass. A recombinant xylan-degrading and xylose-assimilating Saccharomyces cerevisiae strain was engineered by co-expression of the xylanase (xyn2) of Trichoderma reesei, the xylosidase (xlnD) of Aspergillus niger, the Scheffersomyces stipitis xylulose kinase (xyl3) together with the codon-optimized xylose isomerase (xylA) from Bacteroides thetaiotaomicron. Under aerobic conditions, the recombinant strain displayed a complete respiratory mode, resulting in higher yeast biomass production and consequently higher enzyme production during growth on xylose as carbohydrate source. Under oxygen limitation, the strain produced ethanol from xylose at a maximum theoretical yield of ~90 %. This study is one of only a few that demonstrates the construction of a S. cerevisiae strain capable of growth on xylan as sole carbohydrate source by means of recombinant enzymes.

中文翻译：

---

通过共表达内切木聚糖酶，木糖苷酶和细菌木糖异构酶将酿酒酵母工程化为利用木聚糖作为唯一的碳水化合物来源。

木聚糖代表木质纤维素生物质的主要成分，酿酒酵母的利用对于从植物生物质中经济高效地生产乙醇至关重要。通过共同表达里氏木霉的木聚糖酶（xyn2），黑曲霉的木糖苷酶（xlnD），裂殖酵母的木脂多糖木酮糖激酶（xyl3）共同构建重组木聚糖降解和木糖同化的酿酒酵母菌株。拟杆菌（Bacteroides thetaiotaomicron）的最佳木糖异构酶（xylA）。在有氧条件下，重组菌株表现出完全的呼吸模式，导致在以木糖为碳水化合物源生长的过程中产生更高的酵母生物量，从而产生更高的酶。在氧气限制下，该菌株从木糖生产乙醇，最大理论收率约为90％。这项研究是少数证明重组酿酒酵母能够在木聚糖上生长的唯一糖源的菌株之一。