Carboxydocella manganica sp. nov., a thermophilic, dissimilatory Mn(IV)- and Fe(III)-reducing bacterium from a Kamchatka hot spring

Abstract

A thermophilic, anaerobic, dissimilatory Mn(IV)-and Fe(III)-reducing bacterium (strain SLM 61 T ) was isolated from a terrestrial hot spring on the Kamchatka peninsula. The cells were straight rods, 0.5-0.6 mm in diameter and 1.0-6.0 mm long, and exhibited tumbling motility by means of peritrichous flagellation. The strain grew at 26-70 6C, with an optimum at 58-60 6C, and at pH 5.5-8.0, with an optimum at pH 6.5. Growth of SLM 61 T was observed at 0-2.0 % (w/v) NaCl, with an optimum at 0.5 % (w/v). The generation time under optimal growth conditions was 40 min. Strain SLM 61 T grew and reduced Mn(IV), Fe(III) or nitrate with a number of organic acids and complex proteinaceous compounds as electron donors. It was capable of chemolithoautotrophic growth using molecular hydrogen as an electron donor, Fe(III) but not Mn(IV) or nitrate as an electron acceptor and CO 2 as a carbon source. It also was able to ferment pyruvate, yeast extract, glucose, fructose, sucrose and maltose. The G+C content of DNA of strain SLM 61 T was 50.9 mol%. 16S rRNA gene sequence analysis revealed that the closest relative of the isolated organism was Carboxydocella thermautotrophica 41 T (96.9 % similarity). On the basis of its physiological properties and phylogenetic analyses, the isolate is considered to represent a novel species, for which the name Carboxydocella manganica sp. nov. is proposed. The type strain is SLM 61 T (5DSM 23132 T 5VKM B-2609 T ). C. manganica is the first described representative of the genus Carboxydocella that possesses the ability to reduce metals and does not utilize CO.Metal-reducing micro-organisms play important roles in the cycling of carbon and metals in various anaerobic ecosystems, including thermal environments. Dissimilatory Fe(III)-and Mn(IV)-reducing micro-organisms have been found in a variety of thermal biotopes, including continental hot springs, a deep terrestrial subsurface, submarine petroleum reservoirs, deep-sea hydrothermal vents and anthropogenic systems (Lovley et al., 2004;Slobodkin, 2005). Dissimilatory manganese reduction by thermophilic prokaryotes is much less well studied than iron reduction. Of 43 described species of Fe(III)-reducing thermophiles belonging to different phylogenetic groups of the Bacteria and Archaea, the capacity for Mn(IV) reduction has been reported for six species (Slobodkin, 2005). Only two micro-organisms, Bacillus infernus (Boone et al., 1995) and Deferribacter thermophilus (Greene et al., 1997), were first isolated using Mn(IV) as an electron acceptor. In this article, we report the isolation and characterization of a novel anaerobic, thermophilic, Mn(IV)-and Fe(III)-reducing micro-organism from a hydrothermal spring on the Kamchatka peninsula.Strain SLM 61 T was isolated from a sample of sediment collected from a hot spring at the 'Trostnikovyi' field, Uzon Caldera, Kamchatka, Russia. The conditions at the sampling site were 60 u C, pH 6.2, E h 2400 mV. Samples were taken anaerobically in tightly stoppered bottles and transported to the laboratory. Enri...

Ardenticatena maritima gen. nov., sp. nov., a ferric iron- and nitrate-reducing bacterium of the phylum ‘ Chloroflexi ’ isolated from an iron-rich coastal hydrothermal field, and description of Ardenticatenia classis nov.

“…This wide distribution of dissimilatory Fe(III)-reducers in the bacterial and archaeal tree of life (Vargas et al, 1998;Weber et al, 2006) is compatible with the fact that iron is the fourth most abundant element in the Earth's crust. The Fe(III)-reducing thermophiles, including members of the domains 'Bacteria' and 'Archaea', are reported from marine hydrothermal environments, geothermally heated subsurface sediments (Slobodkin & Wiegel, 1997;Sievert et al, 1999;Slobodkin et al, 1999Slobodkin et al, , 2001Reysenbach et al, 2006;and others) and terrestrial hydrothermal environments (Kashefi et al, 2002;Slobodkina et al, 2012;Yoneda et al, 2012;and others). Iron has the potential to serve micro-organisms as an alternative electron acceptor for energy conservation when access to molecular oxygen is limited in these natural environments (Lovley & Phillips, 1986, 1988.…”

Isolation and Characterization ofPseudomonas stutzeriCapable of Reducing Fe(III) and Nitrate from Skarn-type Copper Mine Tailings

“…(Sung et al 2006), Bacillus infernus (Lovley 2000), Geothrix fermentans (Lovley 2000), Pantoea agglomerans (Francis et al 2000), Carboxydocella manganica (Slobodkina et al 2012), et (Table 1). However, there was less information available about an isolate previously obtained from skarn-type copper tailings.…”

A review of the mechanisms of mineral-based metabolism in early Earth analog rock-hosted hydrothermal ecosystems

“…In addition to S°, common minerals capable of supporting microbial metabolism in hot springs include a variety of iron (hydr)oxides (Fig.1) (Fortney et al 2016;Inskeep and McDermott 2005;Kashefi et al 2008b;Langner et al 2001;Lovley et al 2004;Slobodkin 2005;Slobodkina et al 2012), which result from the oxidation of Fe(II) with oxygen (Inskeep et al 2004;Kozubal et al 2008). Dissimilatory iron reduction (DIR) plays a key role on the biogeochemistry of iron in both moderate and higher temperature environments (Lovley et al 2004) and has been suggested to be one of the earliest forms of microbial respiration (Vargas et al 1998).…”