Alicycliphilus denitrificans gen. nov., sp nov., a cyclohexanol-degrading, nitrate-reducing beta-proteobacterium

A facultatively denitrifying bacterium, strain K601(T), was isolated at 30 degreesC from a municipal sewage plant on cyclohexanol as sole carbon source and nitrate as electron acceptor. Under aerobic conditions this strain used acetate, fumarate, lactate, pyruvate, crotonate, indole, glucose, vanillate, 4-hydroxybenzoate, m-cresol, o-cresol and p-cresol. Under denitrifying conditions the strain used cyclohexanol, cyclohexanone, 1,3-cyclohexanedione, 2-cyclohexenone, 1,3-cyclohexanediol (cis and trans), monocarboxylic acids (C-2-C-7) adipate, pimelate, 5-oxocaproate, citrate, 2-oxoglutarate, succinate, malate, crotonate, lactate, pyruvate and fumarate. Cells were short rods, 0.6 mum wide and 1-2 mum long, motile, non-spore-forming, Gram-negative, and catalase- and oxidase-positive. Strain K601(T) used nitrate, nitrite and oxygen as electron acceptors, but not sulfate, sulfite or fumarate. The DNA G+C content of strain K601(T) was 66 mol%. Phylogenetic analysis, based on 16S rDNA sequencing, showed that strain K601(T) represents a separate lineage of the family Comamonadaceae in the beta-subclass of Proteobacteria. Based on the high 16S rDNA sequence divergence and phenotypic characteristics, the name Alicycliphilus denitrificans gen. nov., sp. nov. is proposed for this strain. The type strain is K601(T) (=DSM 14773(T) =CIP 107495(T)).