Pseudomonas chloritidismutans sp. nov., a non-denitrifying, chlorate-reducing bacterium.

Abstract

A Gram-negative, facultatively anaerobic, rod-shaped, dissimilatory chloratereducing bacterium, strain AW-1 T , was isolated from biomass of an anaerobic chlorate-reducing bioreactor. Phylogenetic analysis of the 16S rDNA sequence showed 100 % sequence similarity to Pseudomonas stutzeri DSM 50227 and 986 % sequence similarity to the type strain of P. stutzeri (DSM 5190 T ). The species P. stutzeri possesses a high degree of genotypic and phenotypic heterogeneity. Therefore, eight genomic groups, termed genomovars, have been proposed based upon ∆T m values, which were used to evaluate the quality of the pairing within heteroduplexes formed by DNA-DNA hybridization. In this study, DNA-DNA hybridization between strain AW-1 T and P. stutzeri strains DSM 50227 and DSM 5190 T revealed respectively 805 and 565 % similarity. DNA-DNA hybridization between P. stutzeri strains DSM 50227 and DSM 5190 T revealed 484 % similarity. DNA-DNA hybridization indicated that strain AW-1 T is not related at the species level to the type strain of P. stutzeri. However, strain AW-1 T and P. stutzeri DSM 50227 are related at the species level. The physiological and biochemical properties of strain AW-1 T and the two P. stutzeri strains were compared. A common characteristic of P. stutzeri strains is the ability to denitrify. However, in growth experiments, strain AW-1 T could use only chlorate or oxygen as an electron acceptor and not nitrate, perchlorate or bromate. Strain AW-1 T is the first chlorate-reducing bacterium described that does not possess another oxyanion-reduction pathway. Cell extracts of strain AW-1 T showed chlorate and bromate reductase activities but not nitrate reductase activity. P. stutzeri strains DSM 50227 and DSM 5190 T could use nitrate or oxygen as an electron acceptor, but not chlorate. Chlorate reductase activity, in addition to nitrate reductase activity, was detected in cell extracts of both P. stutzeri strains. Chlorite dismutase activity was absent in extracts of both P. stutzeri strains but was present in extracts of strain AW-1 T . Based on the hybridization experiments and the physiological and biochemical data, it is proposed that strain AW-1 T be classified as a novel species of Pseudomonas, Pseudomonas chloritidismutans sp. nov. The type strain is strain AW-1 T (l DSM 13592 T l ATCC BAA-443 T ).

Two naphthalene degrading bacteria belonging to the genera Paenibacillus and Pseudomonas isolated from a highly polluted lagoon perform different sensitivities to the organic and heavy metal contaminants

“…ORNaP2, indicated by phylogenetic analysis, was close to the Pseudomonas sp. strains SN1 and SB1 isolated from PAH-contaminated sediments of Venice Lagoon, Italy, which were capable of using naphthalene and biphenyl as sole carbon and energy sources, respectively (Marcon et al 2007) and to the species P. chloritidismutans (Wolterink et al 2002) in the same clade. The fact that Pseudomonas sp.…”

Dechloromonas hortensis sp. nov. and strain ASK-1, two novel (per)chlorate-reducing bacteria, and taxonomic description of strain GR-1

“…Growth was followed at the following temperatures: 10, 20, 30, 37 and 50 uC. Strain GR-1 (=DSM 11199) was grown in a medium described before with modifications described by Kengen et al (1999), P. chloritidismutans DSM 13592 T was grown in the medium described by Wolterink et al (2002) and Pseudomonas stutzeri DSM 50227 was grown in the medium described by Matsubara et al (1982) as modified by Coyle et al (1985). Gram-type was determined by Gram staining using the protocol described by Plugge et al (2000).…”

“…For strain MA-1 T , Fe 3+ reduction to Fe 2+ [Fe 3+ applied as iron(III) citrate] was monitored spectrophotometrically at 562 nm using the ferrozine assay described by Lovley & Phillips (1987). Different medium pH values were obtained by changing the CO 2 concentration appropriately in the gas phase, calculated using the Henderson-Hasselbach equation (Wolterink et al, 2002). Growth was followed at the following temperatures: 10, 20, 30, 37 and 50 uC.…”

“…For enrichment and isolation of strain ASK-1, sludge was taken from an anaerobic bioreactor treating chlorate-/bromate-polluted wastewater. Samples from this sludge were also used to isolate P. chloritidismutans DSM 13592 T (Wolterink et al, 2002). Pure cultures of strain ASK-1 were obtained following repeated application of the rolltube dilution method (Hungate, 1969).…”

“…Enrichment and cultivation of strains MA-1 T and ASK-1 were performed in anoxic medium as described previously for Pseudomonas chloritidismutans DSM 13592 T (Wolterink et al, 2002) with the following modifications: The gas phase used was N 2 /CO 2 (80 : 20) and, instead of 0?5 g Na 2 S, 0?2 g Na 2 SO 4 was used as a sulfur source (Wolterink et al, 2002). For the isolation of both strains, chlorate (10 mM) and acetate (10 mM) were used as electron acceptor and electron donor, respectively.…”