在燃料乙醇发酵生产过程中,酿酒酵母经常会受到高浓度乙醇的胁迫,导致乙醇转化率和产量降低。面对高浓度乙醇的胁迫,酿酒酵母也具有应对胁迫的应激机制。在对这种应激机制进行了解的基础上,如能提高酿酒酵母对乙醇的耐受性,对于燃料乙醇生产具有重要意义。在高浓度乙醇胁迫下,酿酒酵母细胞会产生一系列保护性物质,如海藻糖、热激蛋白、脯氨酸等,这些物质能够提高酿酒酵母细胞对乙醇的耐受性。海藻糖作为一种重要的碳源、能量贮藏物质,不仅能稳定细胞膜、蛋白质和核酸等大分子物质,还可增强酿酒酵母对高浓度乙醇的耐受性。此外,酿酒酵母还可以产生大量的热激蛋白,增强酿酒酵母的抗逆性。从海藻糖和热激蛋白在乙醇胁迫下对酿酒酵母细胞保护作用的研究方面进行了综述,并对存在的问题进行了讨论与展望。
During the process of bioethanol production, Saccharomyces cerevisiae cells are often stressed by the accumulated ethanol, which can lead to inhibition of S. cerevisiae growth and low bioethanol yield. To maintain the survival, S. cerevisiae cells have evolved a set of stress responses to environmental stimuli including ethanol stress. Fully understanding the mechanism of S. cerevisiae responses to ethanol will facilitate the development of strategies to improve the ethanol tolerance of S. cerevisiae and contribute to the construction of industrial feasible strains with high bioethanol yield. Under the stress of accumulated ethanol, some protectants, such as trehalose, heat shock proteins (HSPs) , and proline can improve the ethanol tolerance of S. cerevisiae cells. As an important carbon source and energy storage material, trehalose can not only stabilize the cell membranes, proteins and nucleic acids, but also enhance the ethanol tolerance of S. cerevisiae. Furthermore, the up-regulation of HSPs can also improve the ethanol tolerance of S. cerevisiae cells. The progresses of protective roles of trehalose and HSPs for enhancing the ethanol tolerance of S. cerevisiae were focused on.