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Feng X, Kazama D, He S, Nakayama H, Hayashi T, Tokunaga T, Sato K, Kobayashi H. Enrichment of halotolerant hydrogen-oxidizing bacteria and production of high-value-added chemical hydroxyectoine using a hybrid biological-inorganic system. Front Microbiol 2023; 14:1254451. [PMID: 37711693 PMCID: PMC10497747 DOI: 10.3389/fmicb.2023.1254451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/15/2023] [Indexed: 09/16/2023] Open
Abstract
Hybrid biological-inorganic (HBI) systems show great promise as CO2 conversion platforms combining CO2 fixation by hydrogen-oxidizing bacteria (HOB) with water splitting. Herein, halotolerant HOB were enriched using an HBI system with a high-ionic-strength medium containing 180 mM phosphate buffer to identify new biocatalysts. The reactors were inoculated with samples from saline environments and applied with a voltage of 2.0 V. Once an increase in biomass was observed with CO2 consumption, an aliquot of the medium was transferred to a new reactor. After two successive subcultures, Achromobacter xylosoxidans strain H1_3_1 and Mycolicibacterium mageritense strain H4_3_1 were isolated from the reactor media. Genome sequencing indicated the presence of genes for aerobic hydrogen-oxidizing chemolithoautotrophy and synthesis of the compatible solute hydroxyectoine in both strains. Furthermore, both strains produced hydroxyectoine in the reactors under the high-ionic-strength condition, suggesting the potential for new HBI systems using halotolerant HOB to produce high-value-added chemicals.
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Affiliation(s)
- Xiang Feng
- Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Daichi Kazama
- Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Sijia He
- Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Hideki Nakayama
- Department of Environmental Science, Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
| | - Takeshi Hayashi
- Department of Regional Studies and Humanities, Faculty of Education and Human Studies, Akita University, Akita, Japan
| | - Tomochika Tokunaga
- Department of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Kozo Sato
- Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
- Frontier Research Center for Energy and Resource, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Hajime Kobayashi
- Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
- Frontier Research Center for Energy and Resource, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
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