Selection and Development of Stress-tolerant Yeasts for Bioethanol Production

Abstract

Yeast is the major microorganism used to produce ethanol by fermentation. Because fermentation environments are stressful, the fermentation ability of yeast depends greatly on the yeast’s stress tolerance. Stress-tolerant yeasts can produce ethanol in a harsh environment. During the fermentation process of ethanol production, yeasts can be exposed to various stresses, including high temperature, hyperosmolarity, and/or inhibitory substances. The isolation of yeasts tolerant to these stresses and the clarification of their tolerance mechanisms are important for the development of stress-tolerant yeasts for efficient ethanol production. This review focuses on the stress tolerance of yeasts and the use of self-cloning-based gene modification to enhance yeast stress tolerance. We first conducted a search for stress-tolerant yeasts among our stock strains. We also identified stress tolerance-related genes using a Saccharomyces cerevisiae gene deletion strain collection. We then investigated the effects of stress tolerance-related gene overexpression on yeast growth and ethanol production.