{{Short description|Species of bacterium}} {{Speciesbox | image = Mariprofundus ferrooxydans PV-1 stalks TEM image.tif | greatgrandparent_authority = Hördt ''et al''. 2020<ref name="Hördt">{{cite journal |last1=Hördt |first1=Anton |last2=López |first2=Marina García |last3=Meier-Kolthoff |first3=Jan P. |last4=Schleuning |first4=Marcel |last5=Weinhold |first5=Lisa-Maria |last6=Tindall |first6=Brian J. |last7=Gronow |first7=Sabine |last8=Kyrpides |first8=Nikos C. |last9=Woyke |first9=Tanja |last10=Göker |first10=Markus |title=Analysis of 1,000+ Type-Strain Genomes Substantially Improves Taxonomic Classification of Alphaproteobacteria |journal=Frontiers in Microbiology |date=7 April 2020 |volume=11 |page=468 |doi=10.3389/fmicb.2020.00468|pmid=32373076 |pmc=7179689 |doi-access=free }}</ref> | grandparent_authority = Hördt ''et al''. 2020<ref name="Hördt"/> | display_parents = 2 | parent_authority = Emerson ''et al''. 2010<ref name=emerson>{{Cite journal | last1 = Emerson | first1 = D. | last2 = Rentz | first2 = J. A. | last3 = Lilburn | first3 = T. G. | last4 = Davis | first4 = R. E. | last5 = Aldrich | first5 = H. | last6 = Chan | first6 = C. | last7 = Moyer | first7 = C. L. | editor1-last = Reysenbach | editor1-first = Anna-Louise | title = A Novel Lineage of Proteobacteria Involved in Formation of Marine Fe-Oxidizing Microbial Mat Communities | journal = PLOS ONE | volume = 2 | issue = 8 | article-number = e667 | year = 2007 | doi = 10.1371/journal.pone.0000667 | pmc = 1930151 | pmid = 17668050|bibcode = 2007PLoSO...2..667E | doi-access = free }}</ref> | taxon = Mariprofundus ferrooxydans | authority = Emerson ''et al''. 2010<ref name=emerson/> | synonyms = * "Mariprofundales" <small>Makita ''et al''. 2017</small> * "Mariprofundales" <small>Emerson ''et al''. 2007</small> | synonyms_ref = <ref name=lpsn>{{lpsn|m/mariprofundus.html|Mariprofundus}}</ref> }}

'''''Mariprofundus ferrooxydans''''' is a neutrophilic, chemolithotrophic, Gram-negative bacterium which can grow by oxidising ferrous to ferric iron.<ref name=emerson/> It is one of the few members of the class Zetaproteobacteria in the phylum Pseudomonadota. It is typically found in iron-rich deep sea environments, particularly at hydrothermal vents.<ref name="Singer_2011">{{cite journal | vauthors = Singer E, Emerson D, Webb EA, Barco RA, Kuenen JG, Nelson WC, Chan CS, Comolli LR, Ferriera S, Johnson J, Heidelberg JF, Edwards KJ | display-authors = 6 | title = ''Mariprofundus ferrooxydans'' PV-1 the first genome of a marine Fe(II) oxidizing Zetaproteobacterium | journal = PLOS ONE | volume = 6 | issue = 9 | article-number = e25386 | date = 2011-09-23 | pmid = 21966516 | pmc = 3179512 | doi = 10.1371/journal.pone.0025386 | bibcode = 2011PLoSO...625386S | doi-access = free }}</ref> ''M. ferrooxydans'' characteristically produces stalks of solid iron oxyhydroxides that form into iron mats.<ref name="emerson" /> Genes that have been proposed to catalyze Fe(II) oxidation in ''M. ferrooxydans'' are similar to those involved in known metal redox pathways, and thus it serves as a good candidate for a model iron oxidizing organism.<ref name="Singer_2011" />

==Discovery== framed|left|Yellow iron oxide-covered lava rock on the flank of Kamaʻehuakanaloa

The bacterium was isolated from iron-rich microbial mats associated with hydrothermal vents at a submarine volcano, Kamaʻehuakanaloa Seamount (formerly Lōʻihi), near Hawaii, and has only 85.3% 16S similarity to its nearest cultivated species ''Methylophaga marina''. It has a doubling time at 23&nbsp;°C of 12 hours and a curved rod (about 0.5×2–5&nbsp;μm) morphology.<ref name=emerson/>

==Etymology== Despite being validly published,<ref name="lpsn" /> the etymology of the generic epithet is grammatically incorrect, being a concatenation of the Latin neutral ''mare -is'' (the sea) with the Latin masculine adjective ''profundus'' (deep) intended to mean a deep-sea organism (the neuter of ''profundus'' is ''profundum'').<ref name=lpsn/> The specific epithet is ''ferrum'' (Latin noun), iron and ''oxus'' (Greek adjective), acid or sour, and in combined words indicating oxygen. (N.L. v. ''oxydare'', to make acid, to oxidize; N.L. part. adj. ''ferrooxydans'', iron-oxidizing.)<ref name=lpsn/>

== Physiology == ''M. ferrooxydans'' lives in microoxic conditions and uses Fe(II) as an electron donor and oxidizes it to Fe(III) as its main energy acquiring pathway, using oxygen as the electron acceptor and CO<sub>2</sub> as its carbon source.<ref name="Singer_2011" /><ref name="Chen_2019">{{cite journal | vauthors = Chen S, Deng H, Liu G, Zhang D | title = Corrosion of Q235 Carbon Steel in Seawater Containing <i>Mariprofundus ferrooxydans</i> and <i>Thalassospira</i> sp | language = English | journal = Frontiers in Microbiology | volume = 10 | page = 936 | date = 2019 | pmid = 31134004 | pmc = 6517491 | doi = 10.3389/fmicb.2019.00936 | doi-access = free }}</ref> It is a chemolithotroph that requires marine salts and has not been shown to grow heterotrophically.<ref name="emerson" /> Biotic iron oxidation is in competition with abiotic iron oxidation, so ''M. ferrooxydans'' thrives in environments with high concentrations of Fe(II) but low concentrations of oxygen, where biotic oxidation of iron is able to compete with abiotic oxidation.<ref name="emerson" /> Having high concentrations of Fe(II) in the environment is critical since iron oxidation is a low energy-yielding process, and high amounts of iron must be oxidized to yield an adequate amount of energy.<ref>{{Cite journal|last=Keim|first=Carolina N.|date=2011-03-21|title=Arsenic in Biogenic Iron Minerals from a Contaminated Environment|journal=Geomicrobiology Journal|volume=28|issue=3|pages=242–251|doi=10.1080/01490451.2010.493571|s2cid=97696077|issn=0149-0451}}</ref> The proposed model of iron oxidation in ''M. ferrooxydans'' involves oxidation of Fe(II) by an outer membrane iron oxidase, funneling the electron through an electron transport chain made up of cytochromes; oxygen is used as the terminal electron acceptor and then reverse electron transport is used to make NADH.<ref name="Singer_2011" />

== Lifestyle == ''M. ferrooxydans'' cells are Gram-negative curved rods that cycle through two life stages: they have a free-living stage where they are motile, and a second stage where they are oxidizing iron and forming solid iron oxides.<ref name="Singer_2011" /> The fibrous twisted stalks of iron oxyhydroxides extruded by ''M. ferrooxydans'' are found in iron mats and are predicted to consist of an organic matrix which allows the iron oxide structure to form in a manner characteristic of ''M. ferrooxydans''.<ref name="Singer_2011" /><ref name="emerson" /> This organism is also motile and chemotactic, which enables it to move towards appropriate concentrations of oxygen even in the heterogeneous and rapidly changing environment of hydrothermal vents; the organism can rapidly detect and respond to changing oxygen concentrations to allow aerotaxis towards appropriate levels of oxygen.<ref name="Singer_2011" /> Motility allows ''M. ferrooxydans'' to remain in microoxic conditions despite the amount of mixing occurring in its environment, and remain where it can out-compete abiotic iron oxidation to acquire enough energy to survive.<ref name="Singer_2011" />

== Genome == ''M. ferrooxydans'' is capable of fixing CO<sub>2</sub> using RuBisCo genes encoded in its genome; it has multiple different RuBisCo genes which suggests that the organism has adapted to fix CO<sub>2</sub> across a broader spectrum of concentrations of oxygen and carbon dioxide.<ref name="Singer_2011" /> This organism has never been observed to grow heterotrophically, yet its genome encodes for a sugar phosphotransferase system, typically used as a carbohydrate transporter, which is specific for fructose and mannose.<ref name="Singer_2011" /> Carbohydrate transport is thus encoded in its genome, but it is unknown if they can be used as a carbon source or if they are used for forming the carbohydrate scaffolding matrix of the twisted stalks formed by the organism.<ref name="Singer_2011" />

== Role in corrosion == ''M. ferrooxydans'', along with other FeOB, have been implicated in the corrosion of Q235 steel; they are able to form a biofilm on the surface of the steel and cause pitting in the surface of the steel.<ref name="Chen_2019" /> The main products of Q235 steel corrosion caused by ''M. ferrooxydans'' are iron oxides such as FeOOH and Fe<sub>2</sub>O<sub>3</sub>, and this organism also causes acidification of the environment around the attachment site, which allows the pitting to occur.<ref name="Chen_2019" />

==See also== * Pseudomonadota phylogeny for more on placement

==References== {{Reflist|2}}

==External links== *[http://bacdive.dsmz.de/index.php?search=17871&submit=Search Type strain of ''Mariprofundus ferrooxydans'' at Bac''Dive'' - the Bacterial Diversity Metadatabase]

{{Taxonbar|from=Q10957092}}

Category:Zetaproteobacteria Category:Bacteria described in 2010