PHO4 is identified as a promising candidate target for improving high concentration ethanol fermentation efficiency and provides a framework to understand the phosphate-dependent regulatory effects of PHO4 allelic variation and offer a transferable strategy for strain improvement.
Abstract
During high-concentration ethanol fermentation, Saccharomyces cerevisiae often faces multiple stresses, such as high osmotic pressure, ethanol toxicity, and nutrient limitation. These factors collectively limited the production of ethanol. To identify novel targets related to fermentation performance, we employed SHPERM- bCGHR strategy (a marker free allele replacement strategy based on comparative genomics and homologous recombination). We replaced the endogenous PHO4 of the high-producing strain MF01 with the PHO4 allele from MC15, thereby constructing a novel engineered strain MF01-PHO4. Under low-phosphate conditions, compared with the wildtype strain, the PHO5/11/12 genes and ribosomal protein genes showed significant upregulation in MF01-PHO4. These changes were associated with enhanced phosphorus uptake and protein synthesis. Under high phosphate conditions, the PHO4 expression and glycolytic enzyme gene expression in MF01-PHO4 were both lower than MF01, indicating that the substitution of the PHO4 allele may be associated with the coordinated changes in phosphate signal-mediated carbon phosphorus metabolism. This study identifies PHO4 as a promising candidate target for improving high concentration ethanol fermentation efficiency. These findings provide a framework to understand the phosphate-dependent regulatory effects of PHO4 allelic variation and offer a transferable strategy for strain improvement.
Abstract Organisms that thrive in extreme environments provide natural experiments in evolution, revealing the genetic regulators that orchestrate complex phenotypic change. Wine yeast (WY) are specialized strains that are adapted to survive in the wine making environment while producing high concentrations of ethanol. In addition to large genomic changes that differentiate WY from yeast used in other industries, SNP and polyglutamine tract polymorphism in the transcriptional regulator Med15 are associated with the fermentation efficiency and stress response phenotypes of WY. In this study, we investigated the transcriptional differences during wine fermentation in transgenic lab strain yeast having integrated WY MED15 alleles. Compared to the unmodified lab strain (MED15LAB), the same strain in which the MED15 locus was replaced with a MED15 allele from yeast isolated from palm wine, the fermented sap of palm (oil, date, coconut) trees (MED15WY23), exhibited enhanced expression of amino acid biosynthesis genes as well as stress resistance and metabolic adaptation genes. Our experimental data confirm the role of arginine in efficient fermentation and suggest that certain MED15 alleles alter the expression patterns of arginine pathway genes in some cases improving carbon flux under nitrogen stress. The global benefits conferred by natural polymorphisms in a single transcriptional regulator highlight Med15 as a target for engineering of strains devoted to various types of alcohol production.
David G. Cooper, Emma Grunkemeyer, Jan S. Fassler· Microbial Genomics· 0 citations
Saccharomyces cerevisiae is an essential fermentation ingredient in the brewing industry, where its genomic information and fermentation traits profoundly influence final product characteristics. Here, a comprehensive phenotypic and genomic characterisation of the ale yeast strain (CGMCC 2.0002) was performed under simulated brewing conditions. Microscopic observations revealed that the strain exhibits an ellipsoidal morphology with smooth cell surfaces. During brewing, fermentation at 20 °C resulted in accelerated sugar depletion and significantly higher alcohol production compared with fermentation at 11 °C, although its flocculation properties were weaker at the higher temperature. Sensory evaluation indicated that the beer produced at 20 °C exhibited improved colour and taste. Meanwhile, the concentrations of ethyl acetate, isoamyl acetate, catechin, and salicylic acid in the beer all increased. Whole-genome resequencing using the S. cerevisiae S288C reference genome identified 42 711 single nucleotide polymorphisms, 4 725 insertions and deletions, and 562 structural variations in ale yeast. Notably, 21 mutated loci were situated within the essential genes of the glycolytic pathway. These findings establish a solid genomic and physiological baseline for optimising the application of this strain in craft beer production.
Yong-Peng Jia, Hui-Xing Li, Bin Xu et al.· Journal of Food and Nutritio...· 0 citations
This study investigated how syringaldehyde affects Saccharomyces cerevisiae by combining fermentation analysis, cellular characterization, and gene expression analysis, finding that syringaldehyde strongly impaired ethanol production while only slightly affecting biomass accumulation.
60 candidate key genes associated with high xylose-to-ethanol yield in S. stipitis are identified, predominantly involved in the cell cycle pathway, including CDC15 and PHO81.
Hao Zou, Yuan-Jie Zhou, Sui-Yin Lin et al.· Life· 0 citations
This review addresses current knowledge on the regulatory networks controlling glycerol metabolism in yeasts, compassing transport mechanisms, metabolic pathways, transcriptional control and enzyme regulation, and pointed out promising avenues for future research and biotechnological innovation.
Juliana Silva Carneiro Fonseca, W. B. da Silveira· World Journal of Microbiolog...· 0 citations
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