Response mechanism of Saccharomyces cerevisiae under benzoic acid stress in ethanol fermentation

Abstract Sugarcane molasses is an ideal economical raw material for ethanol production because of its wide availability, low cost and nutrient content. However, benzoic acid compounds with toxic effects on yeast cells are commonly found in sugarcane molasses. At present, the molecular mechanism of t...

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Main Authors: Long Xiu-Feng, Xu Yu-Lei, Zhao Xue-Mei
Format: Article
Language:English
Published: Nature Portfolio 2024-11-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-024-80484-1
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author Long Xiu-Feng
Xu Yu-Lei
Zhao Xue-Mei
author_facet Long Xiu-Feng
Xu Yu-Lei
Zhao Xue-Mei
author_sort Long Xiu-Feng
collection DOAJ
description Abstract Sugarcane molasses is an ideal economical raw material for ethanol production because of its wide availability, low cost and nutrient content. However, benzoic acid compounds with toxic effects on yeast cells are commonly found in sugarcane molasses. At present, the molecular mechanism of the toxic effects of benzoic acid on Saccharomyces cerevisiae has not been elucidated. Here, the toxic effect of exogenous benzoic acid on S. cerevisiae GJ2008 cells was studied, and the genes differentially expressed in S. cerevisiae GJ2008 after 1.2 g/L benzoic acid stress were identified via Illumina RNA-Seq technology. The results indicated that benzoic acid significantly inhibited yeast cell growth, prolonged their rapid growth period, and ultimately reduced their biomass. During ethanol fermentation using 250 g/L sucrose under 1.2 g/L benzoic acid stress, several adverse effects were observed, such as high residual sugar content, low ethanol concentration and low fermentation efficiency. In addition, the cell morphology was damaged, the cell membrane permeability increased, intracellular nucleic acid and protein leakage increased, and the malondialdehyde content significantly increased. Moreover, the cells protected themselves by significantly increasing the intracellular glycerol content. Fourier transform infrared spectroscopy proved that benzoic acid could reduce the degree of unsaturation and increase cell membrane permeability by changing the yeast cell wall and cell membrane composition, leading to cell damage and even death. Transcriptomic analysis revealed that under benzoic acid stress, the expression of genes associated with sucrose and starch metabolism, thiamine metabolism, the glycolysis pathway, fructose and mannose metabolism, galactose metabolism and ABC transporters was significantly downregulated. The expression of genes related to ribosomes, lipid metabolism, ribosome biosynthesis, nucleic acid metabolism, arginine and proline metabolism, RNA polymerase, metabolism related to cofactor synthesis, and biosynthesis of valine, leucine, and isoleucine was significantly upregulated. These results indicated that benzoic acid inhibited glycolysis and reduced sugar absorption and utilization and ATP energy supply in yeast cells. In response to stress, genes related to the ribosome bioanabolic pathway were upregulated to promote protein synthesis. On the other hand, the expression of ELO1, SUR4, FEN1 and ERG1 was upregulated, which led to extension of long-chain fatty acids and accumulation of ergosterol to maintain cell membrane structure. In conclusion, this paper provides important insights into the mechanism underlying the toxicity of benzoic acid to yeast cells and for realizing high-concentration ethanol production by sugarcane molasses fermentation.
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spelling doaj-art-8368d8faaea443daa0165e5cf99803302025-08-20T02:22:28ZengNature PortfolioScientific Reports2045-23222024-11-0114112010.1038/s41598-024-80484-1Response mechanism of Saccharomyces cerevisiae under benzoic acid stress in ethanol fermentationLong Xiu-Feng0Xu Yu-Lei1Zhao Xue-Mei2College of Biological and Chemical Engineering, Guangxi University of Science and TechnologyCollege of Biological and Chemical Engineering, Guangxi University of Science and TechnologyCollege of Biological and Chemical Engineering, Guangxi University of Science and TechnologyAbstract Sugarcane molasses is an ideal economical raw material for ethanol production because of its wide availability, low cost and nutrient content. However, benzoic acid compounds with toxic effects on yeast cells are commonly found in sugarcane molasses. At present, the molecular mechanism of the toxic effects of benzoic acid on Saccharomyces cerevisiae has not been elucidated. Here, the toxic effect of exogenous benzoic acid on S. cerevisiae GJ2008 cells was studied, and the genes differentially expressed in S. cerevisiae GJ2008 after 1.2 g/L benzoic acid stress were identified via Illumina RNA-Seq technology. The results indicated that benzoic acid significantly inhibited yeast cell growth, prolonged their rapid growth period, and ultimately reduced their biomass. During ethanol fermentation using 250 g/L sucrose under 1.2 g/L benzoic acid stress, several adverse effects were observed, such as high residual sugar content, low ethanol concentration and low fermentation efficiency. In addition, the cell morphology was damaged, the cell membrane permeability increased, intracellular nucleic acid and protein leakage increased, and the malondialdehyde content significantly increased. Moreover, the cells protected themselves by significantly increasing the intracellular glycerol content. Fourier transform infrared spectroscopy proved that benzoic acid could reduce the degree of unsaturation and increase cell membrane permeability by changing the yeast cell wall and cell membrane composition, leading to cell damage and even death. Transcriptomic analysis revealed that under benzoic acid stress, the expression of genes associated with sucrose and starch metabolism, thiamine metabolism, the glycolysis pathway, fructose and mannose metabolism, galactose metabolism and ABC transporters was significantly downregulated. The expression of genes related to ribosomes, lipid metabolism, ribosome biosynthesis, nucleic acid metabolism, arginine and proline metabolism, RNA polymerase, metabolism related to cofactor synthesis, and biosynthesis of valine, leucine, and isoleucine was significantly upregulated. These results indicated that benzoic acid inhibited glycolysis and reduced sugar absorption and utilization and ATP energy supply in yeast cells. In response to stress, genes related to the ribosome bioanabolic pathway were upregulated to promote protein synthesis. On the other hand, the expression of ELO1, SUR4, FEN1 and ERG1 was upregulated, which led to extension of long-chain fatty acids and accumulation of ergosterol to maintain cell membrane structure. In conclusion, this paper provides important insights into the mechanism underlying the toxicity of benzoic acid to yeast cells and for realizing high-concentration ethanol production by sugarcane molasses fermentation.https://doi.org/10.1038/s41598-024-80484-1Benzoic acidSaccharomyces cerevisiaeEthanol fermentationPhysicochemical propertiesTranscriptomic
spellingShingle Long Xiu-Feng
Xu Yu-Lei
Zhao Xue-Mei
Response mechanism of Saccharomyces cerevisiae under benzoic acid stress in ethanol fermentation
Scientific Reports
Benzoic acid
Saccharomyces cerevisiae
Ethanol fermentation
Physicochemical properties
Transcriptomic
title Response mechanism of Saccharomyces cerevisiae under benzoic acid stress in ethanol fermentation
title_full Response mechanism of Saccharomyces cerevisiae under benzoic acid stress in ethanol fermentation
title_fullStr Response mechanism of Saccharomyces cerevisiae under benzoic acid stress in ethanol fermentation
title_full_unstemmed Response mechanism of Saccharomyces cerevisiae under benzoic acid stress in ethanol fermentation
title_short Response mechanism of Saccharomyces cerevisiae under benzoic acid stress in ethanol fermentation
title_sort response mechanism of saccharomyces cerevisiae under benzoic acid stress in ethanol fermentation
topic Benzoic acid
Saccharomyces cerevisiae
Ethanol fermentation
Physicochemical properties
Transcriptomic
url https://doi.org/10.1038/s41598-024-80484-1
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