National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 6, Higashi 1-1-1, Tsukuba, Ibaraki, 305-8566, Japan.
Appl Microbiol Biotechnol. 2011 Sep;91(6):1593-600. doi: 10.1007/s00253-011-3410-4. Epub 2011 Jun 18.
When the cells of Saccharomyces cerevisiae are exposed to high concentration of ethanol, the content of oleic acid (C18:1n-9) increased as the initial concentration of ethanol increased. Based on this observation, we attempted to confer ethanol tolerance to S. cerevisiae by manipulating fatty acid composition of the cells. Rather than altering OLE1 expression [the desaturase making both C16:1n-7 (palmitoleic acid) and C18:1n-9], we introduced elongase genes. Introduction of rat elongase 1 gene (rELO1) into S. cerevisiae gave cis-vaccenic acid (cis-C18:1n-7) by conversion from C16:1n-7, and the increase in this C18:1 fatty acid did not confer ethanol tolerance to the cells. On the other hand, the introduction of rat elongase 2 gene (rELO2), which elongates C16:0 to C18:0, drastically increased C18:1n-9 content, and the cells acquired ethanol tolerance, emphasizing the specific role of C18:1n-9. Furthermore, the transformant of rELO2 also conferred tolerance to n-butanol, n-propanol, and 2-propanol.
当酿酒酵母的细胞暴露于高浓度乙醇时，随着乙醇初始浓度的增加，油酸（C18:1n-9）的含量增加。基于这一观察结果，我们试图通过操纵细胞的脂肪酸组成来赋予酿酒酵母乙醇耐受性。我们没有改变 OLE1 的表达[使 C16:1n-7（棕榈油酸）和 C18:1n-9 都具有去饱和酶的基因]，而是引入了延长酶基因。向酿酒酵母中引入大鼠延长酶 1 基因（rELO1）可通过将 C16:1n-7 转化为顺式vaccenic 酸（顺式 C18:1n-7），而这种 C18:1 脂肪酸的增加并不能赋予细胞乙醇耐受性。另一方面，大鼠延长酶 2 基因（rELO2）的引入将 C16:0 延长为 C18:0，大大增加了 C18:1n-9 的含量，细胞获得了乙醇耐受性，突出了 C18:1n-9 的特定作用。此外，rELO2 的转化体还赋予了对正丁醇、正丙醇和异丙醇的耐受性。
