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Influence of pH on Inulin Conversion to 2,3-Butanediol by Bacillus licheniformis 24: A Gene Expression Assay

2,3-Butanediol (2,3-BD) is an alcohol highly demanded in the chemical, pharmaceutical, and food industries. Its microbial production, safe non-pathogenic producer strains, and suitable substrates have been avidly sought in recent years. The present study investigated 2,3-BD synthesis by the GRAS Bac...

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Autores principales: Tsigoriyna, Lidia, Arsov, Alexander, Gergov, Emanoel, Petrova, Penka, Petrov, Kaloyan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10531509/
https://www.ncbi.nlm.nih.gov/pubmed/37762368
http://dx.doi.org/10.3390/ijms241814065
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author Tsigoriyna, Lidia
Arsov, Alexander
Gergov, Emanoel
Petrova, Penka
Petrov, Kaloyan
author_facet Tsigoriyna, Lidia
Arsov, Alexander
Gergov, Emanoel
Petrova, Penka
Petrov, Kaloyan
author_sort Tsigoriyna, Lidia
collection PubMed
description 2,3-Butanediol (2,3-BD) is an alcohol highly demanded in the chemical, pharmaceutical, and food industries. Its microbial production, safe non-pathogenic producer strains, and suitable substrates have been avidly sought in recent years. The present study investigated 2,3-BD synthesis by the GRAS Bacillus licheniformis 24 using chicory inulin as a cheap and renewable substrate. The process appears to be pH-dependent. At pH 5.25, the synthesis of 2,3-BD was barely detectable due to the lack of inulin hydrolysis. At pH 6.25, 2,3-BD concentration reached 67.5 g/L with rapid hydrolysis of the substrate but was accompanied by exopolysaccharide (EPS) synthesis. Since inulin conversion by bacteria is a complex process and begins with its hydrolysis, the question of the acting enzymes arose. Genome mining revealed that several glycoside hydrolase (GH) enzymes from different CAZy families are involved. Five genes encoding such enzymes in B. licheniformis 24 were amplified and sequenced: sacA, sacB, sacC, levB, and fruA. Real-time RT-PCR experiments showed that the process of inulin hydrolysis is regulated at the level of gene expression, as four genes were significantly overexpressed at pH 6.25. In contrast, the expression of levB remained at the same level at the different pH values at all-time points. It was concluded that the sacC and sacA/fruA genes are crucial for inulin hydrolysis. They encode exoinulinase (EC 3.2.1.80) and sucrases (EC 3.2.1.26), respectively. The striking overexpression of sacB under these conditions led to increased synthesis of EPS; therefore, the simultaneous production of 2,3-BD and EPS cannot be avoided.
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spelling pubmed-105315092023-09-28 Influence of pH on Inulin Conversion to 2,3-Butanediol by Bacillus licheniformis 24: A Gene Expression Assay Tsigoriyna, Lidia Arsov, Alexander Gergov, Emanoel Petrova, Penka Petrov, Kaloyan Int J Mol Sci Article 2,3-Butanediol (2,3-BD) is an alcohol highly demanded in the chemical, pharmaceutical, and food industries. Its microbial production, safe non-pathogenic producer strains, and suitable substrates have been avidly sought in recent years. The present study investigated 2,3-BD synthesis by the GRAS Bacillus licheniformis 24 using chicory inulin as a cheap and renewable substrate. The process appears to be pH-dependent. At pH 5.25, the synthesis of 2,3-BD was barely detectable due to the lack of inulin hydrolysis. At pH 6.25, 2,3-BD concentration reached 67.5 g/L with rapid hydrolysis of the substrate but was accompanied by exopolysaccharide (EPS) synthesis. Since inulin conversion by bacteria is a complex process and begins with its hydrolysis, the question of the acting enzymes arose. Genome mining revealed that several glycoside hydrolase (GH) enzymes from different CAZy families are involved. Five genes encoding such enzymes in B. licheniformis 24 were amplified and sequenced: sacA, sacB, sacC, levB, and fruA. Real-time RT-PCR experiments showed that the process of inulin hydrolysis is regulated at the level of gene expression, as four genes were significantly overexpressed at pH 6.25. In contrast, the expression of levB remained at the same level at the different pH values at all-time points. It was concluded that the sacC and sacA/fruA genes are crucial for inulin hydrolysis. They encode exoinulinase (EC 3.2.1.80) and sucrases (EC 3.2.1.26), respectively. The striking overexpression of sacB under these conditions led to increased synthesis of EPS; therefore, the simultaneous production of 2,3-BD and EPS cannot be avoided. MDPI 2023-09-14 /pmc/articles/PMC10531509/ /pubmed/37762368 http://dx.doi.org/10.3390/ijms241814065 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Tsigoriyna, Lidia
Arsov, Alexander
Gergov, Emanoel
Petrova, Penka
Petrov, Kaloyan
Influence of pH on Inulin Conversion to 2,3-Butanediol by Bacillus licheniformis 24: A Gene Expression Assay
title Influence of pH on Inulin Conversion to 2,3-Butanediol by Bacillus licheniformis 24: A Gene Expression Assay
title_full Influence of pH on Inulin Conversion to 2,3-Butanediol by Bacillus licheniformis 24: A Gene Expression Assay
title_fullStr Influence of pH on Inulin Conversion to 2,3-Butanediol by Bacillus licheniformis 24: A Gene Expression Assay
title_full_unstemmed Influence of pH on Inulin Conversion to 2,3-Butanediol by Bacillus licheniformis 24: A Gene Expression Assay
title_short Influence of pH on Inulin Conversion to 2,3-Butanediol by Bacillus licheniformis 24: A Gene Expression Assay
title_sort influence of ph on inulin conversion to 2,3-butanediol by bacillus licheniformis 24: a gene expression assay
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10531509/
https://www.ncbi.nlm.nih.gov/pubmed/37762368
http://dx.doi.org/10.3390/ijms241814065
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