<abstract xmlns="http://www.w3.org/1999/xhtml">

Acetic acid (AC) is a major by-product from fermentation processes for producing succinic acid (SA) using <italic>Actinobacillus succinogenes</italic>. Previous experiments have demonstrated that sodium bisulfate (NaHSO3) can significantly decrease AC production by <italic>A. succinogenes</italic> GXAS137 during SA fermentation. However, the mechanism of AC reduction is poorly understood. In this study, the transcriptional profiles of the strain were compared through Illumina RNA-seq to identify differentially expressed genes (DEGs). A total of 210 DEGs were identified by expression analysis: 83 and 127 genes up-regulated and down-regulated, respectively, in response to NaHSO3 treatment. The functional annotation analysis of DEGs showed that the genes were mainly involved in carbohydrates, inorganic ions, amino acid transport, metabolism, and energy production and conversion. The mechanisms of AC reduction might be related to two aspects: (i) the lipoic acid synthesis pathway (LipA, LipB) was significantly down-regulated, which blocked the pathway catalyzed by pyruvate dehydrogenase complex to synthesize acetyl-coenzyme A (acetyl-CoA) from pyruvate; (ii) the expression level of the gene encoding bifunctional acetaldehyde-alcohol dehydrogenase was significantly up-regulated, and this effect facilitated the synthesis of ethanol from acetyl-CoA. However, the reaction of NaHSO3 with the intermediate metabolite acetaldehyde blocked the production of ethanol and consumed acetyl-CoA, thereby decreasing AC production. Thus, our study provides new insights into the molecular mechanism of AC decreased underlying the treatment of NaHSO3 and will deepen the understanding of the complex regulatory mechanisms of <italic>A. succinogenes</italic>.
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</abstract>

Acetic acid (AC) is a major by-product from fermentation processes for producing succinic acid (SA) using Actinobacillus succinogenes. Previous experiments have demonstrated that sodium bisulfate (NaHSO3) can significantly decrease AC production by A. succinogenes GXAS137 during SA fermentation. However, the mechanism of AC reduction is poorly understood. In this study, the transcriptional profiles of the strain were compared through Illumina RNA-seq to identify differentially expressed genes (DEGs). A total of 210 DEGs were identified by expression analysis: 83 and 127 genes up-regulated and down-regulated, respectively, in response to NaHSO3 treatment. The functional annotation analysis of DEGs showed that the genes were mainly involved in carbohydrates, inorganic ions, amino acid transport, metabolism, and energy production and conversion. The mechanisms of AC reduction might be related to two aspects: (i) the lipoic acid synthesis pathway (LipA, LipB) was significantly down-regulated, which blocked the pathway catalyzed by pyruvate dehydrogenase complex to synthesize acetyl-coenzyme A (acetyl-CoA) from pyruvate; (ii) the expression level of the gene encoding bifunctional acetaldehyde-alcohol dehydrogenase was significantly up-regulated, and this effect facilitated the synthesis of ethanol from acetyl-CoA. However, the reaction of NaHSO3 with the intermediate metabolite acetaldehyde blocked the production of ethanol and consumed acetyl-CoA, thereby decreasing AC production. Thus, our study provides new insights into the molecular mechanism of AC decreased underlying the treatment of NaHSO3 and will deepen the understanding of the complex regulatory mechanisms of A. succinogenes.

Comparative Transcriptome Analysis Reveals the Molecular Mechanisms of Acetic Acid Reduction by Adding NaHSO3 in <italic>Actinobacillus succinogenes</italic> GXAS137

Polish Journal of Microbiology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Comparative Transcriptome Analysis Reveals the Molecular Mechanisms of Acetic Acid Reduction by Adding NaHSO in  GXAS137

Acetic acid (AC) is a major by-product from fermentation processes for producing succinic acid (SA) using Actinobacillus succinogenes. Previous experiments...

Comparative Transcriptome Analysis Reveals the Molecular Mechanisms of Acetic Acid Reduction by Adding NaHSO₃ in Actinobacillus succinogenes GXAS137

Article Category: ORIGINAL PAPER

Published Online: Dec 16, 2023

Page range: 399 - 411

Received: Jul 23, 2023

Accepted: Aug 28, 2023

DOI: https://doi.org/10.33073/pjm-2023-036

Keywords
RNA-seq, NaHSO treatment, acetic acid, reduction mechanism

© 2023 Shiyong Li et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Comparative Transcriptome Analysis Reveals the Molecular Mechanisms of Acetic Acid Reduction by Adding NaHSO3 in Actinobacillus succinogenes GXAS137

Article Category: ORIGINAL PAPER

Published Online: Dec 16, 2023

Page range: 399 - 411

Received: Jul 23, 2023

Accepted: Aug 28, 2023

DOI: https://doi.org/10.33073/pjm-2023-036

KeywordsRNA-seq, NaHSO treatment, acetic acid, reduction mechanism

© 2023 Shiyong Li et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Comparative Transcriptome Analysis Reveals the Molecular Mechanisms of Acetic Acid Reduction by Adding NaHSO₃ in Actinobacillus succinogenes GXAS137

Keywords
RNA-seq, NaHSO treatment, acetic acid, reduction mechanism