Desulfoluna spongiiphila sp. nov., a dehalogenating bacterium in the Desulfobacteraceae from the marine sponge Aplysina aerophoba

Abstract

A reductively dehalogenating, strictly anaerobic, sulfate-reducing bacterium, designated strain AA1 T , was isolated from the marine sponge Aplysina aerophoba collected in the Mediterranean Sea and was characterized phenotypically and phylogenetically. Cells of strain AA1 T were Gramnegative, short, curved rods. Growth of strain AA1 T was observed between 20 and 37 6C (optimally at 28 6C) at pH 7-8. NaCl was required for growth; optimum growth occurred in the presence of 25 g NaCl l -1 . Growth occurred with lactate, propionate, pyruvate, succinate, benzoate, glucose and sodium citrate as electron donors and carbon sources and either sulfate or 2-bromophenol as electron acceptors, but not with acetate or butyrate. Strain AA1 T was able to dehalogenate several different bromophenols, and 2-and 3-iodophenol, but not monochlorinated or fluorinated phenols. Lactate, pyruvate, fumarate and malate were not utilized without an electron acceptor. The G+C content of the genomic DNA was 58.5 mol%. The predominant cellular fatty acids were C 14 : 0 , iso-C 14 : 0 , C 14 : 0 3-OH, anteiso-C 15 : 0 , C 16 : 0 , C 16 : 1 v7c and C 18 : 1 v7c. Phylogenetic analysis based on 16S rRNA gene sequence comparisons placed the novel strain within the class Deltaproteobacteria. Strain AA1 T was related most closely to the type strains of Desulfoluna butyratoxydans (96 % 16S rRNA gene sequence similarity), Desulfofrigus oceanense (95 %) and Desulfofrigus fragile (95 %). Based on its phenotypic, physiological and phylogenetic characteristics, strain AA1 T is considered to represent a novel species of the genus Desulfoluna, for which the name Desulfoluna spongiiphila sp. nov. is proposed. The type strain is AA1 T (5DSM 17682 T 5ATCC BAA-1256 T ).The marine environment is a particularly rich source of biogenic organohalides, which are produced by a diversity of marine organisms, including molluscs, algae, polychaetes, jellyfish and sponges (Ashworth & Cormier, 1967;Baker & Duke, 1973;Fielman et al., 1999; Garson et al., 1994;Schmitz & Gopichand, 1978;White & Hager, 1977).A number of sponges (phylum Porifera), such as species of the genus Aplysina, have been shown to produce a wide variety of brominated metabolites, including bromoindoles, bromophenols, polybrominated diphenyl ethers and brominated dibenzo-p-dioxins (Ebel et al., 1997;Gribble, 1999; Norte & Fernández, 1987;Utkina et al., 2001). Brominecontaining metabolites can account for over 10 % of the sponge dry weight (Turon et al., 2000). These compounds may serve as a chemical defence against predators and may inhibit biofouling (Weiss et al., 1996). In addition, Aplysina sponges harbour large amounts of bacteria, which can amount to 40 % of the biomass of the animal, and it has been hypothesized that some of the organobromine compounds may in fact be synthesized by bacteria associated with the sponge (Hentschel et al., 2001(Hentschel et al., , 2003.As the marine environment is a particularly rich source of biogenic organohalides, it is not surprising that dehalogenating bacteria ...

Novel Firmicutes Group Implicated in the Dechlorination of Two Chlorinated Xanthones, Analogues of Natural Organochlorines

“…Indeed, recently a Shewanella sediminis strain was found to contain five putative reductive dehalogenases, one of which was confirmed to be functional in the dechlorination of tetrachloroethene, despite the fact that the genus has never been associated with organohalide respiration (50). Isolates of the genera Dehalococcoides, Dehalogenimonas, "Dehalobium," Dehalobacter, Desulfitobacterium, Anaeromyxobacter, Geobacter, Desulfomonile, Desulfuromonas, Desulfovibrio, Sulfurospirillum, Propionibacterium, Clostridium, and Desulfoluna have been linked to the specific dechlorination activities of several compounds (51,52,53,54), yet dechlorination unattributable to any of these genera has also been frequently observed (23,30,46,55). Our results implicate a group within the Firmicutes, the Gopher group, in the dechlorination of 2,7-dichloroxanthone and 5,7-dichloro-1,3-dihydroxylxanthone and point to the need for additional research on the biodiversity of organohalide respirers.…”

The Family Desulfobacteraceae

“…A sponge (Aplysina aerophoba) from the Mediterranean Sea (Banyuls sur Mer, France) was used as inoculum for the isolation of strain AA1, the type strain of Desulfoluna spongiiphila, with lactate as electron donor and carbon source (Ahn et al 2009). …”

Novel reductive dehalogenases from the marine sponge associated bacterium Desulfoluna spongiiphila

“…The substrate specificity of D. spongiiphila strain AA1, however, is different from that of most well characterized reductive dehalogenating bacteria. Strain AA1 can dehalogenate bromophenols and iodophenols, but not chlorophenols (Ahn et al ., ). Our findings represent an example of a respiratory debrominase and provide an avenue to explore the role of organohalide respiration in the marine halogen cycle.…”