{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,17]],"date-time":"2025-10-17T14:12:33Z","timestamp":1760710353468,"version":"build-2065373602"},"reference-count":48,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2020,9,7]],"date-time":"2020-09-07T00:00:00Z","timestamp":1599436800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["POCI-01-0145-FEDER-016575","UIDB\/04469\/2020","SFRH\/BD\/122623\/2016","PD\/BD\/128030\/2016","SFRH\/BD\/147271\/2019"],"award-info":[{"award-number":["POCI-01-0145-FEDER-016575","UIDB\/04469\/2020","SFRH\/BD\/122623\/2016","PD\/BD\/128030\/2016","SFRH\/BD\/147271\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100008530","name":"European Regional Development Fund","doi-asserted-by":"publisher","award":["NORTE-01-0145-FEDER-000004"],"award-info":[{"award-number":["NORTE-01-0145-FEDER-000004"]}],"id":[{"id":"10.13039\/501100008530","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Long-chain fatty acids (LCFA) are common contaminants in municipal and industrial wastewater that can be converted anaerobically to methane. A low hydrogen partial pressure is required for LCFA degradation by anaerobic bacteria, requiring the establishment of syntrophic relationships with hydrogenotrophic methanogens. However, high LCFA loads can inhibit methanogens, hindering biodegradation. Because it has been suggested that anaerobic degradation of these compounds may be enhanced by the presence of alternative electron acceptors, such as iron, we investigated the effect of sub-stoichiometric amounts of Fe(III) on oleate (C18:1 LCFA) degradation by suspended and granular methanogenic sludge. Fe(III) accelerated oleate biodegradation and hydrogenotrophic methanogenesis in the assays with suspended sludge, with H2-consuming methanogens coexisting with iron-reducing bacteria. On the other hand, acetoclastic methanogenesis was delayed by Fe(III). These effects were less evident with granular sludge, possibly due to its higher initial methanogenic activity relative to suspended sludge. Enrichments with close-to-stoichiometric amounts of Fe(III) resulted in a microbial community mainly composed of Geobacter, Syntrophomonas, and Methanobacterium genera, with relative abundances of 83\u201389%, 3\u20136%, and 0.2\u201310%, respectively. In these enrichments, oleate was biodegraded to acetate and coupled to iron-reduction and methane production, revealing novel microbial interactions between syntrophic LCFA-degrading bacteria, iron-reducing bacteria, and methanogens.<\/jats:p>","DOI":"10.3390\/microorganisms8091375","type":"journal-article","created":{"date-parts":[[2020,9,8]],"date-time":"2020-09-08T00:11:51Z","timestamp":1599523911000},"page":"1375","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Effect of Sub-Stoichiometric Fe(III) Amounts on LCFA Degradation by Methanogenic Communities"],"prefix":"10.3390","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7999-4620","authenticated-orcid":false,"given":"Ana J.","family":"Cavaleiro","sequence":"first","affiliation":[{"name":"Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]},{"given":"Ana P.","family":"Guedes","sequence":"additional","affiliation":[{"name":"Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]},{"given":"S\u00e9rgio A.","family":"Silva","sequence":"additional","affiliation":[{"name":"Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]},{"given":"Ana L.","family":"Arantes","sequence":"additional","affiliation":[{"name":"Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]},{"given":"Jo\u00e3o C.","family":"Sequeira","sequence":"additional","affiliation":[{"name":"Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6037-4248","authenticated-orcid":false,"given":"Andreia F.","family":"Salvador","sequence":"additional","affiliation":[{"name":"Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]},{"given":"Diana Z.","family":"Sousa","sequence":"additional","affiliation":[{"name":"Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"},{"name":"Laboratory of Microbiology, Wageningen University &amp; Research, 6708 WE Wageningen, The Netherlands"}]},{"given":"Alfons J. M.","family":"Stams","sequence":"additional","affiliation":[{"name":"Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"},{"name":"Laboratory of Microbiology, Wageningen University &amp; Research, 6708 WE Wageningen, The Netherlands"}]},{"given":"M. Madalena","family":"Alves","sequence":"additional","affiliation":[{"name":"Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,9,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"538","DOI":"10.1111\/j.1751-7915.2009.00100.x","article-title":"Waste lipids to energy: How to optimize methane production from long-chain fatty acids (LCFA)","volume":"2","author":"Alves","year":"2009","journal-title":"Microb. Biotechnol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"635","DOI":"10.1007\/s10295-006-0099-y","article-title":"Behavior of lipids in biological wastewater treatment processes","volume":"33","author":"Chipasa","year":"2006","journal-title":"J. Ind. Microbiol. Biotechnol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1196\/annals.1419.005","article-title":"Physiology, ecology, phylogeny, and genomics of microorganisms capable of syntrophic metabolism","volume":"1125","author":"McInerney","year":"2008","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1146\/annurev-micro-090110-102844","article-title":"Genomic insights into syntrophy: The paradigm for anaerobic metabolic cooperation","volume":"66","author":"Sieber","year":"2012","journal-title":"Annu. Rev. Microbiol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"6497","DOI":"10.1021\/acs.est.8b00894","article-title":"Insight into the role of facultative bacteria stimulated by microaeration in continuous bioreactors converting LCFA to methane","volume":"52","author":"Duarte","year":"2018","journal-title":"Environ. Sci. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2243","DOI":"10.1016\/j.biortech.2009.11.069","article-title":"Long-chain fatty acids inhibition and adaptation process in anaerobic thermophilic digestion: Batch tests, microbial community structure and mathematical modelling","volume":"101","author":"Palatsi","year":"2010","journal-title":"Bioresour. Technol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"4239","DOI":"10.1128\/AEM.00035-13","article-title":"Activity and viability of methanogens in anaerobic digestion of unsaturated and saturated long-chain fatty acids","volume":"79","author":"Sousa","year":"2013","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1523","DOI":"10.1016\/j.biotechadv.2014.10.005","article-title":"Toxicants inhibiting anaerobic digestion: A review","volume":"32","author":"Chen","year":"2014","journal-title":"Biotechnol. Adv."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"514","DOI":"10.1111\/1751-7915.12365","article-title":"Toxicity of long chain fatty acids towards acetate conversion by Methanosaeta concilii and Methanosarcina mazei","volume":"9","author":"Silva","year":"2016","journal-title":"Microb. Biotechnol."},{"key":"ref_10","unstructured":"Bratby, J. (2006). Coagulation and Flocculation in Water and Wastewater Treatment, IWA Publishing. [2nd ed.]."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3467","DOI":"10.1016\/j.watres.2010.03.023","article-title":"Iron salts dosage for sulfide control in sewers induces chemical phosphorus removal during wastewater treatment","volume":"44","author":"Gutierrez","year":"2010","journal-title":"Water Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"9400","DOI":"10.1021\/acs.est.5b00150","article-title":"The relevance of phosphorus and iron chemistry to the recovery of phosphorus from wastewater: A review","volume":"49","author":"Wilfert","year":"2015","journal-title":"Environ. Sci. Technol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"406","DOI":"10.1007\/BF02529738","article-title":"Desulfuromonas palmitatis sp. nov., a marine dissimilatory Fe(III) reducer that can oxidize long-chain fatty acids","volume":"164","author":"Coates","year":"1995","journal-title":"Arch. Microbiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1615","DOI":"10.1099\/00207713-49-4-1615","article-title":"Geothrix fermentans gen. nov., sp. nov., a novel Fe(III)-reducing bacterium from a hydrocarbon-contaminated aquifer","volume":"49","author":"Coates","year":"1999","journal-title":"Int. J. Syst. Bacteriol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1531","DOI":"10.1128\/aem.62.5.1531-1536.1996","article-title":"Isolation of Geobacter species from diverse sedimentary environments","volume":"62","author":"Coates","year":"1996","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"797","DOI":"10.1038\/nrmicro3347","article-title":"The interplay of microbially mediated and abiotic reactions in the biogeochemical Fe cycle","volume":"12","author":"Melton","year":"2014","journal-title":"Nat. Rev. Microbiol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2636","DOI":"10.1128\/aem.53.11.2636-2641.1987","article-title":"Competitive mechanisms for inhibition of sulfate reduction and methane production in the zone of ferric iron reduction in sediments","volume":"53","author":"Lovley","year":"1987","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"341","DOI":"10.1007\/s10532-004-2057-6","article-title":"Anaerobic biodegradation of vegetable oil and its metabolic intermediates in oil-enriched freshwater sediments","volume":"16","author":"Li","year":"2005","journal-title":"Biodegradation"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3109","DOI":"10.1016\/j.watres.2005.05.021","article-title":"Effect of iron on the sensitivity of hydrogen, acetate, and butyrate metabolism to inhibition by long-chain fatty acids in vegetable-oil-enriched freshwater sediments","volume":"39","author":"Li","year":"2005","journal-title":"Water Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"522","DOI":"10.2175\/106143005X73064","article-title":"Effects of ferric hydroxide on methanogenesis from lipids and long-chain fatty acids in anaerobic digestion","volume":"78","author":"Li","year":"2006","journal-title":"Water Environ. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1128\/mr.55.2.259-287.1991","article-title":"Dissimilatory Fe(III) and Mn(IV) reduction","volume":"55","author":"Lovley","year":"1991","journal-title":"Microbiol. Rev."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1016\/j.femsec.2004.03.017","article-title":"Direct inhibition of methanogenesis by ferric iron","volume":"49","author":"Scholten","year":"2004","journal-title":"FEMS Microbiol. Ecol."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Paulo, L.M., Hidayat, M.R., Moretti, G., Stams, A.J.M., and Sousa, D.Z. (2020). Effect of nickel, cobalt, and iron on methanogenesis from methanol and cometabolic conversion of 1,2-dichloroethene by Methanosarcina. Bark. Biotechnol. Appl. Bioc.","DOI":"10.1002\/bab.1925"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1046\/j.1462-2920.2002.00279.x","article-title":"Reduction of Fe(III) oxide by methanogens in the presence and absence of extracellular quinones","volume":"4","author":"Bond","year":"2002","journal-title":"Environ. Microbiol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1114","DOI":"10.1128\/aem.59.4.1114-1119.1993","article-title":"Growth of syntrophic propionate-oxidizing bacteria with fumarate in the absence of methanogenic bacteria","volume":"59","author":"Stams","year":"1993","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1016\/S0043-1354(00)00241-4","article-title":"Effect of lipids and oleic acid on biomass development in anaerobic fixed-bed reactors. Part I: Biofilm growth and activity","volume":"35","author":"Alves","year":"2001","journal-title":"Water Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"683","DOI":"10.1128\/aem.51.4.683-689.1986","article-title":"Organic matter mineralization with the reduction of ferric iron in anaerobic sediments","volume":"51","author":"Lovley","year":"1986","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"3485","DOI":"10.1099\/ijs.0.061598-0","article-title":"Geobacter anodireducens sp. nov., an exoelectrogenic microbe in bioelectrochemical systems","volume":"64","author":"Sun","year":"2014","journal-title":"Int. J. Syst. Evol. Microbiol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/j.biortech.2008.06.018","article-title":"Detection and quantification of long chain fatty acids in liquid and solid samples and its relevance to understand anaerobic digestion of lipids","volume":"100","author":"Neves","year":"2009","journal-title":"Bioresour. Technol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"4516","DOI":"10.1073\/pnas.1000080107","article-title":"Global patterns of 16S rRNA diversity at a depth of millions of sequences per sample","volume":"108","author":"Caporaso","year":"2011","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"e01733-18","DOI":"10.1128\/AEM.01733-18","article-title":"Inhibition studies with 2-bromoethanesulfonate reveal a novel syntrophic relationship in anaerobic oleate degradation","volume":"85","author":"Salvador","year":"2019","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"e00415","DOI":"10.1128\/genomeA.00415-16","article-title":"Complete genome sequence of Geobacter anodireducens SD-1T, a salt-tolerant exoelectrogenic microbe in bioelectrochemical systems","volume":"4","author":"Sun","year":"2016","journal-title":"Genome. Announc."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1128\/br.41.1.100-180.1977","article-title":"Energy conservation in chemotrophic anaerobic bacteria","volume":"41","author":"Thauer","year":"1977","journal-title":"Bacteriol. Rev."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"834","DOI":"10.1038\/362834a0","article-title":"Ferrous iron oxidation by anoxygenic phototrophic bacteria","volume":"362","author":"Widdel","year":"1993","journal-title":"Nature"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Aklujkar, M., Young, N.D., Holmes, D., Chavan, M., Risso, C., Kiss, H.E., Han, C.S., Land, M.L., and Lovley, D.R. (2010). The genome of Geobacter bemidjiensis, exemplar for the subsurface clade of Geobacter species that predominate in Fe(III)-reducing subsurface environments. BMC Genom., 11.","DOI":"10.1186\/1471-2164-11-490"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1111\/j.1462-2920.2008.01740.x","article-title":"Effect of sulfate on methanogenic communities that degrade unsaturated and saturated long-chain fatty acids (LCFA)","volume":"11","author":"Sousa","year":"2009","journal-title":"Environ. Microbiol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"3847","DOI":"10.1128\/aem.62.10.3847-3857.1996","article-title":"Competition and coexistence of sulfate-reducing and methanogenic populations in anaerobic biofilms","volume":"62","author":"Raskin","year":"1996","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1045","DOI":"10.1007\/s00253-008-1391-8","article-title":"Competition and coexistence of sulfate-reducing bacteria, acetogens and methanogens in a lab-scale anaerobic bioreactor as affected by changing substrate to sulfate ratio","volume":"78","author":"Dar","year":"2008","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"492","DOI":"10.3389\/fmicb.2015.00492","article-title":"Methanogenic archaea and sulfate reducing bacteria co-cultured on acetate: Team work or coexistence?","volume":"6","author":"Ozuolmez","year":"2015","journal-title":"Front. Microbiol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1591","DOI":"10.1002\/bit.260230717","article-title":"Mechanism of inhibition caused by long-chain fatty acids in anaerobic digestion process","volume":"23","author":"Hanaki","year":"1981","journal-title":"Biotechnol. Bioeng."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1016\/S0141-0229(97)00050-1","article-title":"Acute toxicity of oleate to acetate-utilizing methanogens in mesophilic and thermophilic anaerobic sludges","volume":"21","author":"Hwu","year":"1997","journal-title":"Enzym. Microb. Technol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"351","DOI":"10.2166\/wst.1996.0570","article-title":"Comparative toxicity of long-chain fatty acid to anaerobic sludges from various origins","volume":"34","author":"Hwu","year":"1996","journal-title":"Water Sci. Technol."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"568","DOI":"10.1038\/nrmicro2166","article-title":"Electron transfer in syntrophic communities of anaerobic bacteria and archaea","volume":"7","author":"Stams","year":"2009","journal-title":"Nat. Rev. Microbiol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1099\/00207713-51-2-581","article-title":"Geobacter hydrogenophilus, Geobacter chapellei and Geobacter grbiciae, three new, strictly anaerobic, dissimilatory Fe(III)-reducers","volume":"51","author":"Coates","year":"2001","journal-title":"Int. J. Syst. Evol. Microbiol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1667","DOI":"10.1099\/ijs.0.63417-0","article-title":"Geobacter bemidjiensis sp. nov. and Geobacter psychrophilus sp. nov., two novel Fe(III)-reducing subsurface isolates","volume":"55","author":"Nevin","year":"2005","journal-title":"Int. J. Syst. Evol. Microbiol."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Bratlie, M.S., Johansen, J., Sherman, B.T., Huang da, W., Lempicki, R.A., and Drabl\u00f8s, F. (2010). Gene duplications in prokaryotes can be associated with environmental adaptation. BMC Genom., 11.","DOI":"10.1186\/1471-2164-11-588"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"5869","DOI":"10.1128\/AEM.01517-16","article-title":"Secondary mineralization of ferrihydrite affects microbial methanogenesis in Geobacter-Methanosarcina cocultures","volume":"82","author":"Tang","year":"2016","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1698","DOI":"10.1021\/es00058a023","article-title":"Speciation of Fe(II) and Fe(III) in contaminated aquifer sediments using chemical extraction techniques","volume":"28","author":"Heron","year":"1994","journal-title":"Environ. Sci. Technol."}],"container-title":["Microorganisms"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2607\/8\/9\/1375\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:07:45Z","timestamp":1760177265000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2607\/8\/9\/1375"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,9,7]]},"references-count":48,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2020,9]]}},"alternative-id":["microorganisms8091375"],"URL":"https:\/\/doi.org\/10.3390\/microorganisms8091375","relation":{},"ISSN":["2076-2607"],"issn-type":[{"type":"electronic","value":"2076-2607"}],"subject":[],"published":{"date-parts":[[2020,9,7]]}}}