Efficient substrate utilization is the first and most important prerequisite for economically viable production of biofuels and chemicals by microbial cell factories. However, production rates and yields are often compromised by low transport rates of substrates across biological membranes and their diversion to competing pathways. This is especially true when common chassis organisms are engineered to utilize nonphysiological feedstocks. Here, we addressed this problem by constructing an artificial complex between an endogenous sugar transporter and a heterologous xylose isomerase in Saccharomyces cerevisiae. Direct feeding of the enzyme through the transporter resulted in acceleration of xylose consumption and substantially diminished production of xylitol as an undesired side product, with a concomitant increase in the production of ethanol. This underlying principle could also likely be implemented in other biotechnological applications.

有效利用底物是微生物细胞工厂经济可行地生产生物燃料和化学品的首要条件。然而，底物跨生物膜的低运输速率及其转移至竞争途径常常会损害生产率和产量。当常见的底盘生物被设计为利用非生理性原料时，尤其如此。在这里，我们通过在酿酒酵母中构建内源糖转运蛋白和异源木糖异构酶之间的人工复合物来解决此问题。。通过转运蛋白直接进料酶导致木糖消耗的加速，并且作为不希望的副产物的木糖醇的生产大大减少，同时乙醇的产量增加。该基本原理也可能在其他生物技术应用中实现。