Alcaligenes aquatilis sp. nov., a novel bacterium from sediments of the Weser Estuary, Germany, and a salt marsh on Shem Creek in Charleston Harbor, USA.

Four nitrite-dissimilating strains, isolated from Weser Estuary sediments, were investigated using a polyphasic taxonomic approach. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains belong to the 'Betaproteobacteria' and are related to the genus Alcaligenes. The highest level of sequence similarity (100 %) was found with strain M3A (=ATCC 700596), a dimethyl sulfide-producing marine isolate that was included in this study. DNA-DNA hybridizations between the five strains and related Alcaligenes faecalis strains confirmed that the former belong to a single and novel species within the genus Alcaligenes. The isolates are Gram-negative, motile, rod-shaped cells with a DNA G+C content of about 56 mol%. The whole-cell fatty acid profiles of the isolates were very similar and included C(16 : 0), C(17 : 0) cyclo, C(18 : 1)omega7c, summed feature 2 (comprising any combination of C(12 : 0) aldehyde, an unknown fatty acid of equivalent chain length 10.928, C(16 : 1) iso I and C(14 : 0) 3-OH) and summed feature 3 (C(15 : 0) iso 2-OH and/or C(16 : 1)omega7c) as the major fatty acid components. On the basis of their phylogenetic, genomic and phenotypic properties, the five novel strains can be assigned to the genus Alcaligenes as a novel species, for which the name Alcaligenes aquatilis sp. nov. is proposed. The type strain is LMG 22996T (=CCUG 50924T).