Gordonia phosphorivorans sp. nov., isolated from a wastewater bioreactor with phosphorus removal

Abstract

Two Gram-stain-positive, non-endospore-forming actinobacteria (Ca8Tand Ca14) were isolated from a bioreactor with extensive phosphorus removal. Based on 16S rRNA gene sequence similarity comparisons, strains Ca8T and Ca14 were shown to belong to the genus Gordonia and were most closely related to Gordonia hirsuta DSM 44140T (98.0 % sequence similarity) and Gordonia hydrophobica DSM 44015T (97.2 %). In comparison with the sequences of the type strains of all other species of the genus Gordonia tested, similarities were below 97 %. The quinone systems of the strains were determined to consist predominantly of MK-9H2. The polar lipid profile for both organisms consisted of diphosphatidylglycerol, phosphatidylglycerol, phospatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. Whole-organism hydrolysates contained meso-diaminopimelic acid as the diamino acid of the peptidoglycan; mycolic acids were detected as well. These chemotaxonomic traits and the major fatty acids, which were C16 : 1 cis-9, C16 : 0 and C18 : 1 and tuberculostearic acid strongly supported the grouping of strains Ca8T and Ca14 into the genus Gordonia . The two strains showed a DNA–DNA similarity of 96 %. DNA–DNA hybridizations of strain Ca8T with G. hirsuta DSM 44140T and G. hydrophobica DSM 44015T resulted in values of 26.3 and 25.0 %, respectively. These results and those of the physiological and biochemical tests allowed a clear phenotypic differentiation of strains Ca8T and Ca14 from the most closely related species of the genus Gordonia . It is concluded that strains Ca8T and Ca14 represent a novel species, for which the name Gordonia phosphorivorans sp. nov. is proposed, with the type strain Ca8T ( = DSM 45630T = CCUG 61533T = CCM 7957T = LMG 26648T).