Defluviimonas denitrificans gen. nov., sp nov., and Pararhodobacter aggregans gen. nov., sp nov., non-phototrophic Rhodobacteraceae from the biofilter of a marine aquaculture

Three Gram-negative bacterial strains were isolated from the biofilter of a recirculating marine aquaculture. They were non-pigmented rods, mesophiles, moderately halophilic, and showed chemo-organoheterotrophic growth on various sugars, fatty acids, and amino acids, with oxygen as electron acceptor; strains D9-3(T) and D11-58 were in addition able to denitrify. Phototrophic or fermentative growth could not be demonstrated. Phylogenetic analysis of the 16S rRNA gene sequences placed D9-3(T) and D11-58, and D1-19(T) on two distinct branches within the alpha-3 proteobacterial Rhodobacteraceae, affiliated with, but clearly separate from, the genera Rhodobacter, Rhodovulum, and Rhodobaca. Based on morphological, physiological, and 16S rRNA-based phylogenetic characteristics, the isolated strains are proposed as new species of two novel genera, Defluviimonas denitrificans gen. nov., sp. nov. (type strain D9-3(T) = DSM 18921(T) = ATCC BAA-1447(T); additional strain D11-58 = DSM19039 = ATCC BAA-1448) and Pararhodobacter aggregans gen. nov., sp. nov (type strain D1 19(T) = DSM 18938(T) = ATCC BAA-1446(T)). (C) 2011 Elsevier GmbH. All rights reserved.