Quantitative analysis of amino acid excretion by Methanothermobacter marburgensis under N2-fixing conditions
Abstract Methanogenic archaea (methanogens) possess fascinating metabolic characteristics, such as the ability to fix molecular nitrogen (N2). Methanogens are of biotechnological importance due to the ability to produce methane (CH4) from molecular hydrogen (H2) and carbon dioxide (CO2) and to excre...
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Nature Portfolio
2025-01-01
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| Online Access: | https://doi.org/10.1038/s41598-025-87686-1 |
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| author | Barbara Reischl Benjamin Schupp Hayk Palabikyan Barbara Steger-Mähnert Christian Fink Simon K.-M. R. Rittmann |
| author_facet | Barbara Reischl Benjamin Schupp Hayk Palabikyan Barbara Steger-Mähnert Christian Fink Simon K.-M. R. Rittmann |
| author_sort | Barbara Reischl |
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| description | Abstract Methanogenic archaea (methanogens) possess fascinating metabolic characteristics, such as the ability to fix molecular nitrogen (N2). Methanogens are of biotechnological importance due to the ability to produce methane (CH4) from molecular hydrogen (H2) and carbon dioxide (CO2) and to excrete proteinogenic amino acids. This study focuses on analyzing the link between biological methanogenesis and amino acid excretion under N2-fixing conditions. Among five hydrogenotrophic, autotrophic methanogens, Methanothermobacter marburgensis was prioritized and further cultivated in closed batch cultivation mode under N2-fixing conditions. M. marburgensis was grown on chemically defined minimal medium with different concentrations of ammonium in a H2/CO2/N2 atmosphere. This enabled the quantification of ammonia uptake, N2-fixation, amino acid excretion and the conversion of H2/CO2 to CH4. To quantify N2-fixation rates in a mass balance setting a novel method has been established. The method utilizes the pressure drop below a certain threshold pressure in closed batch cultivation mode – the threshold pressure for N 2 -fixation (THpN2fix). Using the THpN2fix method, volumetric N2-fixation rates of M. marburgensis as high as 0.91 mmol L−1 h−1 were determined. Excretion of amino acids was found with highest detected values of glutamic acid, alanine, glycine and asparagine. The highest total amino acid excretion of 7.5 µmol L−1 h−1 was detected with H2/CO2/N2 at an ammonium concentration of 40 mmol L−1. This study sheds light on the link between methanogenesis, biological N2-fixation, and proteinogenic amino acid excretion. The concomitant production of amino acids and CH4 could become of biotechnological relevance in an integrated approach coupling biomethanation and N2-fixation in a biorefinery concept. |
| format | Article |
| id | doaj-art-73f79374b93b454b868e4fa247d26fe3 |
| institution | Kabale University |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Nature Portfolio |
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| series | Scientific Reports |
| spelling | doaj-art-73f79374b93b454b868e4fa247d26fe32025-02-02T12:17:34ZengNature PortfolioScientific Reports2045-23222025-01-0115111310.1038/s41598-025-87686-1Quantitative analysis of amino acid excretion by Methanothermobacter marburgensis under N2-fixing conditionsBarbara Reischl0Benjamin Schupp1Hayk Palabikyan2Barbara Steger-Mähnert3Christian Fink4Simon K.-M. R. Rittmann5Archaea Physiology & Biotechnology Group, Department of Functional and Evolutionary Ecology, University of ViennaArchaea Physiology & Biotechnology Group, Department of Functional and Evolutionary Ecology, University of ViennaArchaea Physiology & Biotechnology Group, Department of Functional and Evolutionary Ecology, University of ViennaBioOceanography and Marine Biology, Department of Functional and Evolutionary Ecology, University of ViennaArkeon GmbHArchaea Physiology & Biotechnology Group, Department of Functional and Evolutionary Ecology, University of ViennaAbstract Methanogenic archaea (methanogens) possess fascinating metabolic characteristics, such as the ability to fix molecular nitrogen (N2). Methanogens are of biotechnological importance due to the ability to produce methane (CH4) from molecular hydrogen (H2) and carbon dioxide (CO2) and to excrete proteinogenic amino acids. This study focuses on analyzing the link between biological methanogenesis and amino acid excretion under N2-fixing conditions. Among five hydrogenotrophic, autotrophic methanogens, Methanothermobacter marburgensis was prioritized and further cultivated in closed batch cultivation mode under N2-fixing conditions. M. marburgensis was grown on chemically defined minimal medium with different concentrations of ammonium in a H2/CO2/N2 atmosphere. This enabled the quantification of ammonia uptake, N2-fixation, amino acid excretion and the conversion of H2/CO2 to CH4. To quantify N2-fixation rates in a mass balance setting a novel method has been established. The method utilizes the pressure drop below a certain threshold pressure in closed batch cultivation mode – the threshold pressure for N 2 -fixation (THpN2fix). Using the THpN2fix method, volumetric N2-fixation rates of M. marburgensis as high as 0.91 mmol L−1 h−1 were determined. Excretion of amino acids was found with highest detected values of glutamic acid, alanine, glycine and asparagine. The highest total amino acid excretion of 7.5 µmol L−1 h−1 was detected with H2/CO2/N2 at an ammonium concentration of 40 mmol L−1. This study sheds light on the link between methanogenesis, biological N2-fixation, and proteinogenic amino acid excretion. The concomitant production of amino acids and CH4 could become of biotechnological relevance in an integrated approach coupling biomethanation and N2-fixation in a biorefinery concept.https://doi.org/10.1038/s41598-025-87686-1BiotechnologyMicrobiologyArchaeaAnaerobesMethanogensDiazotrophy |
| spellingShingle | Barbara Reischl Benjamin Schupp Hayk Palabikyan Barbara Steger-Mähnert Christian Fink Simon K.-M. R. Rittmann Quantitative analysis of amino acid excretion by Methanothermobacter marburgensis under N2-fixing conditions Scientific Reports Biotechnology Microbiology Archaea Anaerobes Methanogens Diazotrophy |
| title | Quantitative analysis of amino acid excretion by Methanothermobacter marburgensis under N2-fixing conditions |
| title_full | Quantitative analysis of amino acid excretion by Methanothermobacter marburgensis under N2-fixing conditions |
| title_fullStr | Quantitative analysis of amino acid excretion by Methanothermobacter marburgensis under N2-fixing conditions |
| title_full_unstemmed | Quantitative analysis of amino acid excretion by Methanothermobacter marburgensis under N2-fixing conditions |
| title_short | Quantitative analysis of amino acid excretion by Methanothermobacter marburgensis under N2-fixing conditions |
| title_sort | quantitative analysis of amino acid excretion by methanothermobacter marburgensis under n2 fixing conditions |
| topic | Biotechnology Microbiology Archaea Anaerobes Methanogens Diazotrophy |
| url | https://doi.org/10.1038/s41598-025-87686-1 |
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