Glucose is a preferred carbon source for most living organisms. The metabolism and regulation of glucose utilization are well studied mostly for Saccharomyces cerevisiae. Xylose is the main pentose sugar released from the lignocellulosic biomass, which has a high potential as a renewable feedstock for bioethanol production. The thermotolerant yeast Ogataea (Hansenula) polymorpha, in contrast to S. cerevisiae, is able to metabolize and ferment not only glucose but also xylose. However, in non-conventional yeasts, the regulation of glucose and xylose metabolism remains poorly understood. In this study, we characterize the role of transcriptional factors Mig1, Mig2, Tup1 and Hap4 in the natural xylose-fermenting yeast O. polymorpha. The deletion of MIG1 had no significant influence on ethanol production either from xylose or glucose, however the deletion of both MIG1 and MIG2 reduced the amount of ethanol produced from these sugars. The deletion of HAP4-A and TUP1 genes resulted in increased ethanol production from xylose. Inversely, the overexpression of HAP4-A and TUP1 genes reduced ethanol production during xylose alcoholic fermentation. Thus, HAP4-A and TUP1 are involved in repression of xylose metabolism and fermentation in yeast O. polymorpha and their deletion could be a viable strategy to improve ethanol production from this pentose.

中文翻译：

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Mig1、Mig2、Tup1 和 Hap4 转录因子在调节耐热酵母 Ogataea polymorpha 木糖和葡萄糖发酵中的作用

葡萄糖是大多数生物体的首选碳源。葡萄糖利用的代谢和调节主要针对酿酒酵母进行了充分研究。木糖是木质纤维素生物质释放的主要戊糖，它作为生物乙醇生产的可再生原料具有很高的潜力。的耐热性酵母Ogataea属（汉逊酵母）多形，而相比之下，酿酒酵母，是能够代谢和发酵不仅葡萄糖而且木糖。然而，在非常规酵母中，葡萄糖和木糖代谢的调节仍然知之甚少。在这项研究中，我们描述了转录因子 Mig1、Mig2、Tup1 和 Hap4 在天然木糖发酵酵母中的作用。. MIG1的缺失对木糖或葡萄糖的乙醇生产没有显着影响，但是MIG1和MIG2的缺失减少了这些糖产生的乙醇量。的缺失HAP4-A和TUP1基因导致由木糖增加的乙醇生产。相反，HAP4-A和TUP1基因的过表达降低了木糖酒精发酵过程中的乙醇产量。因此，HAP4-A和TUP1涉及木糖代谢和发酵的抑制在酵母O.多形 并且它们的缺失可能是提高这种戊糖乙醇产量的可行策略。