School of Life Science and Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
J Biotechnol. 2010 Oct 15;150(2):209-14. doi: 10.1016/j.jbiotec.2010.09.932. Epub 2010 Sep 17.
Ethanol plays an important role in substituting the increasingly limited oil as the high-value, renewable fuel. In our previous studies, we successfully established the conversion of glycerol to ethanol by overexpression of pGcyaDak with pGup1Cas in Saccharomyces cerevisiae. In addition to increasing ethanol production using glycerol as substrate, we minimized the synthesis of glycerol, which is the main by-product in ethanol fermentation processing. The glycerol production pathway was impaired by deletion of the genes FPS1 and GPD2. Strains deleted for both FPS1 and GPD2 reduce glycerol production and become highly sensitive to osmotic stress. We provide osmotic protection in YPH499fps1Δgpd2Δ by overexpression of Gup1. In this study, S. cerevisiae using glycerol as substrate was modified through one-step gene disruption for redirection of glycerol carbon flux into ethanol by the deletion of two glycerol production genes, FPS1 and GPD2. The overall ethanol production in the modified strain YPH499fps1Δgpd2Δ (pGcyaDak, pGupCas) was about 4.4 gl⁻¹. These results demonstrate the possibility of providing protection against osmotic stress while simultaneously increasing ethanol and reducing glycerol production in S. cerevisiae strains using glycerol as a carbon source.
乙醇在替代日益有限的石油作为高价值可再生燃料方面发挥着重要作用。在我们之前的研究中，我们通过在酿酒酵母中过表达 pGcyaDak 和 pGup1Cas，成功地将甘油转化为乙醇。除了利用甘油作为底物增加乙醇产量外，我们还最大限度地减少了甘油的合成，甘油是乙醇发酵过程中的主要副产物。甘油生产途径通过缺失 FPS1 和 GPD2 基因而受到损害。缺失 FPS1 和 GPD2 的菌株减少了甘油的产生，并且对渗透压胁迫高度敏感。我们通过过表达 Gup1 在 YPH499fps1Δgpd2Δ 中提供渗透压保护。在这项研究中，通过一步基因敲除，使用甘油作为底物的酿酒酵母被修饰，通过缺失两个甘油生产基因 FPS1 和 GPD2，将甘油碳通量重新定向为乙醇。修饰菌株 YPH499fps1Δgpd2Δ（pGcyaDak，pGupCas）中的总乙醇产量约为 4.4 gl⁻¹。这些结果表明，在使用甘油作为碳源的酿酒酵母菌株中，有可能在提供渗透压保护的同时，增加乙醇产量并减少甘油生产。
