Department of Molecular Genetics and Biotechnology, Institute of Cell Biology, NAS of Ukraine, Drahomanov Street, 14/16, Lviv 79005, Ukraine.
Department of Microbiology and Molecular Genetics, University of Rzeszow, Cwiklinskiej 2D, Building D10, Rzeszow 35-601, Poland.
FEMS Yeast Res. 2021 May 18;21(4). doi: 10.1093/femsyr/foab029.
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.
葡萄糖是大多数生物的首选碳源。糖代谢和葡萄糖利用的调节在酿酒酵母(Saccharomyces cerevisiae)中得到了很好的研究。木糖是木质纤维素生物质中释放的主要戊糖，具有作为生物乙醇生产可再生原料的巨大潜力。与酿酒酵母不同，耐热酵母奥格特海默氏菌（Hansenula）polymorpha不仅能够代谢和发酵葡萄糖，还能够代谢和发酵木糖。然而，在非常规酵母中，糖代谢和发酵的调节仍然知之甚少。在本研究中，我们研究了转录因子 Mig1、Mig2、Tup1 和 Hap4 在天然木糖发酵酵母 O. polymorpha 中的作用。MIG1 的缺失对木糖或葡萄糖的乙醇生产没有显著影响，然而 MIG1 和 MIG2 的缺失都降低了这些糖的乙醇产量。HAP4-A 和 TUP1 基因的缺失导致木糖的乙醇产量增加。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 参与了酵母 O. polymorpha 中木糖代谢和发酵的抑制，其缺失可能是提高该戊糖乙醇产量的可行策略。
