Aquamicrobium ahrensii sp. nov. and Aquamicrobium segne sp. nov., isolated from experimental biofilters

Abstract

Two groups of Gram-negative, aerobic bacterial strains previously isolated from experimental biofilters were investigated to determine their taxonomic position. Based on their 16S rRNA gene sequences, these isolates formed two distinct groups within the genus Aquamicrobium . The gene sequence similarities of the new isolates to the type strains of Aquamicrobium species were below 98.3 %. The presence of ubiquinone-10, C18 : 1 cis 11 as the predominant fatty acid and a polar lipid pattern with phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol and phosphatidylethanolamine was in accordance with the characteristics of this genus. The results of DNA–DNA hybridization, biochemical tests and chemotaxonomic properties allowed genotypic and phenotypic differentiation of the strains from all recognized species of the genus Aquamicrobium . Therefore, the isolates were assigned to two novel species of this genus for which the names Aquamicrobium ahrensii sp. nov. (type strain 905/1T = DSM 19730T = CCUG 55251T) and Aquamicrobium segne sp. nov. (type strain 1006/1T = DSM 19714T = CCUG 55250T) are proposed. An emended description of the genus Aquamicrobium is also presented.