Voronovsky Andriy Y, Ryabova Olena B, Verba Olena V, Ishchuk Olena P, Dmytruk Kostyantyn V, Sibirny Andriy A
Institute of Cell Biology, NAS of Ukraine, Drahomanov Street 14/16, Lviv 79005, Ukraine.
FEMS Yeast Res. 2005 Nov;5(11):1055-62. doi: 10.1016/j.femsyr.2005.09.001. Epub 2005 Oct 10.
The thermotolerant methylotrophic yeast Hansenula polymorpha is able to ferment xylose to ethanol at high temperatures. H. polymorpha xylose reductase and xylitol dehydrogenase are involved during the first steps of this fermentation. In this article, expression of bacterial xylA genes coding for xylose isomerases from Escherichia coli or Streptomyces coelicolor in the yeast H. polymorpha was shown. The expression was achieved by integration of the xylA genes driven by the promoter of the H. polymorpha glyceraldehyde-3-phosphate dehydrogenase gene ( HpGAP) into the H. polymorpha genome. Expression of the bacterial xylose isomerase genes restored the ability of the H. polymorpha Deltaxyl1 mutant to grow in a medium with xylose as the sole carbon source. This mutant has a deletion of the XYL1 gene encoding xylose reductase and is not able to grow in the xylose medium. The H. polymorpha Deltaxyl1(xylA) transformants displayed xylose isomerase activities, which were near 20% of that of the bacterial host strain. The transformants did not differ from the yeast wild-type strain with respect to ethanol production in xylose medium.
嗜热甲基营养酵母多形汉逊酵母能够在高温下将木糖发酵为乙醇。多形汉逊酵母木糖还原酶和木糖醇脱氢酶参与该发酵的第一步。在本文中，展示了编码来自大肠杆菌或天蓝色链霉菌的木糖异构酶的细菌木糖A基因在多形汉逊酵母中的表达。该表达通过将由多形汉逊酵母甘油醛-3-磷酸脱氢酶基因（HpGAP）启动子驱动的木糖A基因整合到多形汉逊酵母基因组中来实现。细菌木糖异构酶基因的表达恢复了多形汉逊酵母Deltaxyl1突变体在以木糖为唯一碳源的培养基中生长的能力。该突变体缺失编码木糖还原酶的XYL1基因，无法在木糖培养基中生长。多形汉逊酵母Deltaxyl1(xylA)转化体表现出木糖异构酶活性，其活性接近细菌宿主菌株的20%。在木糖培养基中，转化体在乙醇生产方面与酵母野生型菌株没有差异。
