Psychrilyobacter atlanticus gen. nov., sp. nov., a marine member of the phylum Fusobacteria that produces H2 and degrades nitramine explosives under low temperature conditions

Abstract

A Gram-negative and obligately anaerobic marine bacterium, strain HAW-EB21(T), was isolated in a previous study from marine sediment from the Atlantic Ocean, near Halifax Harbor, Canada, and found to have the potential to degrade both hexahydro-1,3,5-trinitro-1,3,5-triazine and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine. In the present study, phylogenetic analyses showed that strain HAW-EB21(T) was only distantly related to the genera Propionigenium and Ilyobacter with 6.6-7.5 % and 8.2-10.5 % dissimilarity as measured by 16S rRNA and 23S rRNA gene sequence analyses, respectively. Strain HAW-EB21(T) displayed unique properties in being psychrotrophic (18.5 degrees C optimum) and unable to utilize any of the carbon substrates (succinate, l-tartrate, 3-hydroxybutyrate, quinate or shikimate) used for isolating members of the genera Propionigenium and Ilyobacter. Strain HAW-EB21(T) utilized glucose, fructose, maltose, N-acetyl-d-glucosamine, citrate, pyruvate, fumarate and Casitone as carbon sources and produced H(2) and acetate as the major fermentation products. Cells grown at 10 degrees C produced C(15 : 1) (30 %), C(16 : 1)omega7 (15 %) and C(16 : 0) (16 %) as major membrane fatty acids. The novel strain had a genomic DNA G+C content of 28.1 mol%, lower than the values of the genera Ilyobacter and Propionigenium. Based on the present results, the novel isolate is suggested to be a member of a new genus for which the name Psychrilyobacter atlanticus gen. nov., sp. nov. is proposed. The type strain of the type species is HAW-EB21(T) (=DSM 19335(T)=JCM 14977(T)).