Enriched hydrogen-oxidizing microbiomes show a high diversity of co-existing hydrogen-oxidizing bacteria

• Published in: Applied microbiology and biotechnology Vol. 103; no. 19; pp. 8241 - 8253
• Main Authors: Ehsani, Elham, Dumolin, Charles, Arends, Jan B. A., Kerckhof, Frederiek-Maarten, Hu, Xiaona, Vandamme, Peter, Boon, Nico
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-10-2019; Springer; Springer Nature B.V
• Subjects: Achromobacter; Ammonium; Ammonium Compounds - metabolism; Bacteria; Bacteria - classification; Bacteria - genetics; Bacteria - metabolism; Bacteriological Techniques; Biomedical and Life Sciences; Biotechnology; Carbon dioxide; Carbon Dioxide - metabolism; Carbon sources; Chemical properties; Cluster Analysis; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; Energy resources; Energy sources; Environmental Biotechnology; Heterotrophic organisms; Heterotrophs; Hydrogen; Hydrogen - metabolism; Hydrogen enrichment; Industrial applications; Inoculum; Life Sciences; Metagenomics; Microbial activity; Microbial colonies; Microbial Genetics and Genomics; Microbiology; Microbiomes; Microorganisms; Oxidation; Oxidation-Reduction; Oxygen; Oxygen - metabolism; Oxygen enrichment; Phylogeny; RNA, Ribosomal, 16S - genetics; rRNA 16S; Sequence Analysis, DNA; Soil bacteria; Soil Microbiology; Soils; Belgium; Heterotrophs; HOB enrichment; HOB isolation; Microbial composition; Hydrogen-oxidizing bacteria
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-019-10082-z

While numerous reports exist on the axenic culturing of different hydrogen-oxidizing bacteria (HOB), knowledge about the enrichment of microbial communities growing on hydrogen, oxygen, and carbon dioxide as sole carbon and energy sources remains negligible. We want to elucidate if in such enrichments, most enriched populations are HOBs or heterotrophic organisms. In the present study, bacteria enriched from a soil sample and grown over 5 transfers using a continuous supply of hydrogen, oxygen, and carbon dioxide to obtain an enriched autotrophic hydrogen-oxidizing microbiome. The success of the enrichment was evaluated by monitoring ammonium consumption and biomass concentration for 120 days. The shift in the microbial composition of the original soil inoculum and all transfers was observed based on 16S rRNA amplicon sequencing. The hydrogen-oxidizing facultative chemolithoautotroph
Hydrogenophaga electricum
was isolated and found to be one of the abundant species in most transfers. Moreover,
Achromobacter
was isolated both under heterotrophic and autotrophic conditions, which was characterized as a hydrogen-oxidizing bacterium. The HOB enrichment condition constructed in this study provided an environment for HOB to develop and conquer in all transfers. In conclusion, we showed that enrichments on hydrogen, oxygen, and carbon dioxide as sole carbon and energy sources contain a diverse mixture of HOB and heterotrophs that resulted in a collection of culturable isolates. These isolates can be useful for further investigation for industrial applications.