Serpentinicella alkaliphila gen. nov., sp. nov., a novel alkaliphilic anaerobic bacterium isolated from the serpentinite-hosted Prony hydrothermal field, New Caledonia

Abstract

A novel anaerobic, alkaliphilic, Gram-stain-positive, spore-forming bacterium was isolated from a carbonaceous hydrothermal chimney in Prony Bay, New Caledonia. This bacterium, designated strain 3bT, grew at temperatures from 30 to 43 °C (optimum 37 °C) and at pH between 7.8 and 10.1 (optimum 9.5). Added NaCl was not required for growth (optimum 0-0.2 %, w/v), but was tolerated at up to 4 %. Yeast extract was required for growth. Strain 3bT utilized crotonate, lactate and pyruvate, but not sugars. Crotonate was dismutated to acetate and butyrate. Lactate was disproportionated to acetate and propionate. Pyruvate was degraded to acetate plus trace amounts of hydrogen. Growth on lactate was improved by the addition of fumarate, which was used as an electron acceptor and converted to succinate. Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate, nitrite, FeCl3, Fe(III)-citrate, Fe(III)-EDTA, chromate, arsenate, selenate and DMSO were not used as terminal electron acceptors. The G+C content of the genomic DNA was 33.2 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the isolate is a member of the family Clostridiaceae, order Clostridiales within the phylum Firmicutes. Strain 3bT was most closely related to 'Alkaliphilus hydrothermalis' FatMR1T (92.2 % 16S rRNA gene sequence similarity), and was positioned approximately equidistantly between the genera Alkaliphilus, Anaerovirgula and Natronincola. On the basis of phylogenetic, genetic, chemotaxonomic and physiological properties, strain 3bT is proposed to represent a novel species of a new genus, for which the name Serpentinicella alkaliphila gen. nov., sp. nov. is proposed. The type strain of Serpentinicella alkaliphila is 3bT (=DSM 100013T=JCM 30645T).

Metagenomic and PCR-Based Diversity Surveys of [FeFe]-Hydrogenases Combined with Isolation of Alkaliphilic Hydrogen-Producing Bacteria from the Serpentinite-Hosted Prony Hydrothermal Field, New Caledonia

“…As shown in Figure 6B, the alkaliphilic, highly efficient H 2 -producing ST07 culture was dominated by the strain PROH2 (sharing 99.9 and 96.8% 16S rRNA identity with Acetoanaerobium pronyense and Clostridium sticklandii , respectively; Mei et al, 2014; Bes et al, 2015). The RKC cultures were dominated by the alkaliphilic strain 3b having Alkaliphilus hydrothermalis as its closest phylogenetic relative (92.3% 16S rRNA identity), hence representing a novel species of a new genus in the order Clostridiales , for which the name “ Serpentinicella alkaliphila ” has been recently proposed (Mei et al, 2016). The BdJC cultures were dominated by strain BJ2 closely related to Exiguobacterium profundum (99.5% 16S rRNA identity) a facultative anaerobe originating from a deep-sea hydrothermal vent and belonging to the order Bacillales .…”

Hydrostatic Pressure Helps to Cultivate an Original Anaerobic Bacterium From the Atlantis Massif Subseafloor (IODP Expedition 357): Petrocella atlantisensis gen. nov. sp. nov.

“…In this study, our main goal was to cultivate anaerobic microorganisms inhabiting the rocky subseafloor associated with active serpentinization characterized by circulation of high pH fluids enriched in H 2 , CH 4 and other organic molecules abiotically produced. To the best of our knowledge, the only cultivated anaerobes were isolated by our team from a shallow submarine serpentinite-hosted hydrothermal system, analogous to the LCHF, located in the Prony bay (New Caledonia) (Ben Aissa et al, 2014, 2015; Mei et al, 2014, 2016; Bes et al, 2015). In the present study, putative moderately halo-alkaliphilic bacteria (related to Alkalibacterium , Halomonas , Tissierella and the proposed genus Petrocella ) were enriched and in some case isolated in cultures carried out at pH 8.5, while the only isolate obtained from the cultures at pH 10 (in the common range of pH values observed in low temperature serpentinizing systems) was a strain of Bacillus circulans , a facultative anaerobe, spore-forming, frequently detected in soils, but no obligate alkaliphile as targeted by the pH conditions.…”

Habitability of the marine serpentinite subsurface: a case study of the Lost City hydrothermal field

“…Repeated attempts to cultivate the Methanosarcinales that are associated with abundant biofilms in the chimneys of both the Lost City and a similar hydrothermal system at the Prony Bay (New Caledonia) have failed to produce a pure isolate [12,45], although potential activity experiments have detected metabolism of methane at 70-80°C and pH 9-10 [12]. All isolates reported from Prony Bay are mesophilic, fermentative clostridia, and none of them can grow above pH 10 or 10.5 [46][47][48].…”