# Venenivibrio stagnispumantis

Venenivibrio stagnispumantis strain CP.B2 is the first microorganisms isolated from the terrestrial hot spring Champagne Pool (75 °C, pH 5.5) in Waiotapu, New Zealand.

## Morphology

The cells are motile and slightly curved rods (1.04 to 1.56 μm long and 0.33 to 0.41 μm wide).

## Growth conditions

The novel bacterium is an obligate chemolithotroph capable of utilizing H$_2$ as electron donor, O$_2$ as corresponding electron acceptor and CO$_2$ as carbon source. Venenivibrio stagnispumantis gains metabolic energy using the "Knallgas" reaction H$_2$ + ½ O$_2$ → H$_2$O. For growth either elemental sulphur (S$^0$) or thiosulfate (S$_2$O$_3$$^{2−}$) is required. Growth is observed under thermophilic conditions between 45 °C and 75 °C (optimum 70 °C), under moderate acidophilic conditions between pH 4.8 and 5.8 (optimum pH 5.4) and under microaerophilic conditions between 1.0% and 10.0% (v/v) O$_2$ (optimum between 4.0% and 8.0% (v/v) O$_2$).

## Phylogeny

Phylogenetic analysis based on 16S rDNA sequences indicate that strain CP.B2 belongs to the order Aquificales and represents the type strain of a novel species of a new genus within the family Hydrogenothermaceae. The 16S rRNA gene sequence for strain CP.B2 is deposited in the GenBank nucleotide sequence database under accession number DQ989208. The G+C content of the genomic DNA is 29.3 mol% which is the lowest G+C content reported for a species of the order Aquificales.

## Tolerance to arsenic and antimony compounds

Venenivibrio stagnispumantis displays tolerance to relatively high concentrations of arsenic and antimony compounds. Cells grew in the presence of up to 8 mM arsenite (As$^{3+}$), 15 mM trivalent antimony (Sb$^{3+}$), and >20 mM arsenate (As$^{5+}$) but growth was not observed when As$^{3+}$ and As$^{5+}$ were provided as the sole electron donor and acceptor pair.

## Nomenclature

Ve.ne.ni.vi' bri.o. (Latin: the vibrio of poison) stag.ni.spu.man' tis. (Latin: from the bubbling pool, pertaining to Champagne Pool).

## Culture collection

Venenivibrio stagnispumantis strain CP.B2 is deposited in the Japan Collection of Microorganisms under JCM 14244, in the American Type Culture Collection under ATCC BAA-1398 and in the German Collection of Microorganisms under DSM 18763.

## Culture medium

| Venenivibrio stagnispumantis culture medium | |
| NaOH | 0.15 g |
| KCl | 0.50 g |
| MgCl$_2$ • 6 H$_2$O | 1.36 g |
| MgSO$_4$ • 7 H$_2$O | 7.00 g |
| Na$_2$S$_2$O$_3$ • 5 H$_2$O | 2.00 g |
| CaCl$_2$ • 2 H$_2$O | 0.40 g |
| NH$_4$Cl | 0.20 g |
| K$_2$HPO$_4$ | 0.25 g |
| Trace minerals (100x) | 10.00 ml |
| MES | 1.95 g |
| Distilled water | make up to 1000.00 ml |
The pH of the medium is adjusted to 5.5, distributed into culture vessels and autoclaved under CO$_2$. After the inoculation the initial gas phase is replaced with H$_2$ / CO$_2$ / O$_2$ (79% / 15% / 6%) and pressurized to 170 kPa.
| Trace mineral solution (100x) | |
| Na$_2$-EDTA • 2 H$_2$O | 500.00 mg |
| CoCl$_2$ • 6 H$_2$O | 150.00 mg |
| MnCl$_2$ • 4 H$_2$O | 100.00 mg |
| FeSO$_4$ • 7 H$_2$O | 100.00 mg |
| ZnCl$_2$ | 100.00 mg |
| AlCl$_3$ • 6 H$_2$O | 40.00 mg |
| Na$_2$WO$_4$ • 2 H$_2$O | 30.00 mg |
| CuCl$_2$ • 2 H$_2$O | 20.00 mg |
| Ni$_2$SO$_4$ • 6 H$_2$O | 20.00 mg |
| Na$_2$SeO$_3$ | 10.00 mg |
| H$_3$BO$_3$ | 10.00 mg |
| Na$_2$MoO$_4$ • 2 H$_2$O | 10.00 mg |
| Distilled water | make up to 1000.00 ml |
The pH of the solution is adjusted to 3.0 with HCl.