{"doi":"10.1128/aem.65.3.1009-1014.1999","title":"High-Affinity Methane Oxidation by a Soil Enrichment Culture Containing a Type II Methanotroph","abstract":"<jats:title>ABSTRACT</jats:title>\n          <jats:p>\n            Methanotrophic bacteria in an organic soil were enriched on gaseous mixing ratios of &lt;275 parts per million of volume (ppmv) of methane (CH\n            <jats:sub>4</jats:sub>\n            ). After 4 years of growth and periodic dilution (&gt;10\n            <jats:sup>20</jats:sup>\n            times the initial soil inoculum), a mixed culture was obtained which displayed an apparent half-saturation constant [\n            <jats:italic>\n              K\n              <jats:sub>m(app)</jats:sub>\n            </jats:italic>\n            ] for CH\n            <jats:sub>4</jats:sub>\n            of 56 to 186 nM (40 to 132 ppmv). This value was the same as that measured in the soil itself and about 1 order of magnitude lower than reported values for pure cultures of methane oxidizers. However, the\n            <jats:italic>\n              K\n              <jats:sub>m(app)</jats:sub>\n            </jats:italic>\n            increased when the culture was transferred to higher mixing ratios of CH\n            <jats:sub>4</jats:sub>\n            (1,000 ppmv, or 1%). Denaturing gradient gel electrophoresis of the enrichment grown on &lt;275 ppmv of CH\n            <jats:sub>4</jats:sub>\n            revealed a single gene product of\n            <jats:italic>pmoA</jats:italic>\n            , which codes for a subunit of particulate methane monooxygenase. This suggested that only one methanotroph species was present. This organism was isolated from a sample of the enrichment culture grown on 1% CH\n            <jats:sub>4</jats:sub>\n            and phylogenetically positioned based on its 16S rRNA,\n            <jats:italic>pmoA</jats:italic>\n            , and\n            <jats:italic>mxaF</jats:italic>\n            gene sequences as a type II strain of the\n            <jats:italic>Methylocystis/Methylosinus</jats:italic>\n            group. A coculture of this strain with a\n            <jats:italic>Variovorax</jats:italic>\n            sp., when grown on &lt;275 ppmv of CH\n            <jats:sub>4</jats:sub>\n            , had a\n            <jats:italic>\n              K\n              <jats:sub>m(app)</jats:sub>\n            </jats:italic>\n            (129 to 188 nM) similar to that of the initial enrichment culture. The data suggest that the affinity of methanotrophic bacteria for CH\n            <jats:sub>4</jats:sub>\n            varies with growth conditions and that the oxidation of atmospheric CH\n            <jats:sub>4</jats:sub>\n            observed in this soil is carried out by type II methanotrophic bacteria which are similar to characterized species.\n          </jats:p>","journal":"Applied and Environmental Microbiology","year":1999,"id":682320,"datarank":0.7886243058041673,"base_score":5.2574953720277815,"endowment":5.2574953720277815,"self_citation_contribution":0.7886243058041673,"citation_network_contribution":0.0,"self_endowment_contribution":0.7886243058041673,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":191,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1743936,"name":"Werner Liesack","orcid":null,"position":1,"is_corresponding":false},{"id":1782573,"name":"Thilo Henckel","orcid":null,"position":2,"is_corresponding":false},{"id":1782574,"name":"Roger Knowles","orcid":null,"position":3,"is_corresponding":false},{"id":1782575,"name":"Ralf Conrad","orcid":null,"position":4,"is_corresponding":false},{"id":1782572,"name":"Peter F. Dunfield","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"High-Affinity Methane Oxidation by a Soil Enrichment Culture Containing a Type II Methanotroph","abstract":"<jats:title>ABSTRACT</jats:title>\n          <jats:p>\n            Methanotrophic bacteria in an organic soil were enriched on gaseous mixing ratios of &lt;275 parts per million of volume (ppmv) of methane (CH\n            <jats:sub>4</jats:sub>\n            ). After 4 years of growth and periodic dilution (&gt;10\n            <jats:sup>20</jats:sup>\n            times the initial soil inoculum), a mixed culture was obtained which displayed an apparent half-saturation constant [\n            <jats:italic>\n              K\n              <jats:sub>m(app)</jats:sub>\n            </jats:italic>\n            ] for CH\n            <jats:sub>4</jats:sub>\n            of 56 to 186 nM (40 to 132 ppmv). This value was the same as that measured in the soil itself and about 1 order of magnitude lower than reported values for pure cultures of methane oxidizers. However, the\n            <jats:italic>\n              K\n              <jats:sub>m(app)</jats:sub>\n            </jats:italic>\n            increased when the culture was transferred to higher mixing ratios of CH\n            <jats:sub>4</jats:sub>\n            (1,000 ppmv, or 1%). Denaturing gradient gel electrophoresis of the enrichment grown on &lt;275 ppmv of CH\n            <jats:sub>4</jats:sub>\n            revealed a single gene product of\n            <jats:italic>pmoA</jats:italic>\n            , which codes for a subunit of particulate methane monooxygenase. This suggested that only one methanotroph species was present. This organism was isolated from a sample of the enrichment culture grown on 1% CH\n            <jats:sub>4</jats:sub>\n            and phylogenetically positioned based on its 16S rRNA,\n            <jats:italic>pmoA</jats:italic>\n            , and\n            <jats:italic>mxaF</jats:italic>\n            gene sequences as a type II strain of the\n            <jats:italic>Methylocystis/Methylosinus</jats:italic>\n            group. A coculture of this strain with a\n            <jats:italic>Variovorax</jats:italic>\n            sp., when grown on &lt;275 ppmv of CH\n            <jats:sub>4</jats:sub>\n            , had a\n            <jats:italic>\n              K\n              <jats:sub>m(app)</jats:sub>\n            </jats:italic>\n            (129 to 188 nM) similar to that of the initial enrichment culture. The data suggest that the affinity of methanotrophic bacteria for CH\n            <jats:sub>4</jats:sub>\n            varies with growth conditions and that the oxidation of atmospheric CH\n            <jats:sub>4</jats:sub>\n            observed in this soil is carried out by type II methanotrophic bacteria which are similar to characterized species.\n          </jats:p>","is_dataset_classified":null,"base_score":5.2574953720277815,"endowment":5.2574953720277815,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"10049856","pmcid":"PMC91137","openalex_id":"https://openalex.org/W1578036325","authors":[],"funders":[],"total_grants":0,"fwci":4.3075,"citation_percentile":0.94980019,"influential_citations":0,"citation_trend":[{"year":2012,"count":4},{"year":2013,"count":6},{"year":2014,"count":7},{"year":2015,"count":14},{"year":2016,"count":5},{"year":2017,"count":6},{"year":2018,"count":9},{"year":2019,"count":5},{"year":2020,"count":9},{"year":2021,"count":1},{"year":2022,"count":2},{"year":2023,"count":4},{"year":2024,"count":6},{"year":2026,"count":2}],"oa_status":"bronze","license":"https://journals.asm.org/non-commercial-tdm-license","oa_locations":[{"url":"https://aem.asm.org/content/aem/65/3/1009.full.pdf","host_type":"journal"},{"url":"https://aem.asm.org/content/aem/65/3/1009.full.pdf","host_type":"publisher"},{"url":"https://journals.asm.org/doi/pdf/10.1128/AEM.65.3.1009-1014.1999","host_type":"publisher"},{"url":"https://doi.org/10.1128/aem.65.3.1009-1014.1999","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/10049856","host_type":"repository"},{"url":"http://europepmc.org/pmc/articles/PMC91137","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/91137","host_type":"repository"}],"fields_of_study":["Microbial metabolism and enzyme function","Microbial bioremediation and biosurfactants","Anaerobic Digestion and Biogas Production"],"mesh_terms":["Culture Media","DNA, Bacterial","Electrophoresis, Polyacrylamide Gel","Kinetics","Methane","Methylococcaceae","Molecular Sequence Data","Oxidation-Reduction","Oxygenases","Phylogeny","RNA, Ribosomal, 16S","Soil Microbiology","Polymerase Chain Reaction","Genes, rRNA"],"keywords":["Methanotroph","Methane monooxygenase","Anaerobic oxidation of methane","Enrichment culture","Bacteria","Methane","Temperature gradient gel electrophoresis","Chemistry","Environmental chemistry","Soil microbiology","Microorganism","Biology","16S ribosomal RNA","Organic chemistry"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Life in Land"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[{"name":"gen"}],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-17T20:04:55.940372Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}