An organic acid-tolerant HAA1 -overexpression mutant of an industrial bioethanol strain of Saccharomyces cerevisiae and its application to the production of bioethanol from sugarcane molasses

摘要: Bacterial contamination is known as a major cause of the reduction in ethanol yield during bioethanol production by Saccharomyces cerevisiae. Acetate an effective agent for prevention bacterial contamination, but it negatively affects fermentation ability S. We have proposed that combined use organic acids including acetate and lactate yeast strains tolerant to may be elimination principally lactic acid (LAB) contamination. In previous study employing laboratory cerevisiae strains, we showed overexpression HAA1 gene, which encodes transcriptional activator, could useful molecular breeding method acetate-tolerant strains. present study, constructed HAA1-overexpressing diploid strain (MAT a/α, named ER HAA1-OP) derived from industrial Ethanol Red (ER). HAA1-OP tolerance not only also lactate, this was dependent on increased expression gene. The almost equivalent parent process sugarcane molasses absence acetate. addition at 0.5% (w/v, pH 4.5) inhibited strain, such inhibition observed using HAA1-OP.