Characterization of the xylose-transporting properties of yeast hexose transporters and their influence on xylose utilization
Characterization of the xylose-transporting properties of yeast hexose transporters and their influence on xylose utilization
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DOI：
10.1099/00221287-148-9-2783
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发表时间：
2002-09-01
期刊：
影响因子：
2.8
通讯作者：
Boles, E
中科院分区：
文献类型：
--
作者：
Hamacher, T;Becker, J;Boles, E
为了通过微生物细胞从植物生物量中经济可行的乙醇产生，木糖的发酵很重要。由于木糖的摄取可能是通过重组木糖利用酿酒酵母细胞进行木糖发酵的限制步骤，因此对木糖摄取的研究进行了研究。删除了所有18种己糖转运蛋白基因后，细胞占据木糖上的能力丧失了。在该菌株中重新引入单个己糖 - 转运蛋白基因表明，在中间木糖浓度下，酵母高和中间亲属转运蛋白HXT4，HXT5，HXT7和GA12是重要的木糖转移蛋白。来自细菌和植物细胞的几种异源单糖转运蛋白没有赋予足够的摄取活性来恢复木糖的生长。在有氧条件下，在木糖利用酵母菌菌株中的木糖转运蛋白的过表达不会导致木糖的生长更快，也不会在厌氧条件下提高木糖发酵速率。这项研究的结果表明，在研究的条件下和酵母菌菌株中，木糖的摄取并不能确定木糖通量。
For an economically feasible production of ethanol from plant biomass by microbial cells, the fermentation of xylose is important. As xylose uptake might be a limiting step for xylose fermentation by recombinant xylose-utilizing Saccharomyces cerevisiae cells a study of xylose uptake was performed. After deletion of all of the 18 hexose-transporter genes, the ability of the cells to take up and to grow on xylose was lost. Reintroduction of individual hexose-transporter genes in this strain revealed that at intermediate xylose concentrations the yeast high- and intermediate-affinity transporters Hxt4, Hxt5, Hxt7 and Ga12 are important xylose-transporting proteins. Several heterologous monosaccharide transporters from bacteria and plant cells did not confer sufficient uptake activity to restore growth on xylose. Overexpression of the xylose-transporting proteins in a xylose-utilizing PUA yeast strain did not result in faster growth on xylose under aerobic conditions nor did it enhance the xylose fermentation rate under anaerobic conditions. The results of this study suggest that xylose uptake does not determine the xylose flux under the conditions and in the yeast strains investigated.