title: The diversity of PAH-degrading bacteria in a deep-sea water column above the Southwest Indian Ridge.
abstract: The bacteria involved in organic pollutant degradation in pelagic deep-sea environments are largely unknown. In this report, the diversity of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria was analyzed in deep-sea water on the Southwest Indian Ridge (SWIR). After enrichment with a PAH mixture (phenanthrene, anthracene, fluoranthene, and pyrene), nine bacterial consortia were obtained from depths of 3946-4746 m. While the consortia degraded all four PAHs when supplied in a mixture, when PAHs were tested individually, only phenanthrene supported growth. Thus, degradation of the PAH mixture reflected a cometabolism of anthracene, fluoranthene, and pyrene with phenanthrene. Further, both culture-dependent and independent methods revealed many new bacteria involved in PAH degradation. Specifically, the alpha and gamma subclasses of Proteobacteria were confirmed as the major groups within the communities. Additionally, Actinobacteria, the CFB group and Firmicutes were detected. Denaturing Gradient Gel Electrophoresis (DGGE) analysis showed that bacteria closely affiliated with Alcanivorax, Novosphingobium, and Rhodovulum occurred most frequently in different PAH-degrading consortia. By using general heterotrophic media, 51 bacteria were isolated from the consortia and of these 34 grew with the PAH mixture as a sole carbon source. Of these, isolates most closely related to Alterierythrobacter, Citricella, Erythrobacter, Idiomarina, Lutibacterium, Maricaulis, Marinobacter, Martelella, Pseudidiomarina, Rhodobacter, Roseovarius, Salipiger, Sphingopyxis, and Stappia were found to be PAH degraders. To the best of our knowledge, this is the first time these bacteria have been identified in this context. In summary, this report revealed significant diversity among the PAH-degrading bacteria in the deep-sea water column. These bacteria may play a role in PAH removal in deep-sea environments.
authors.affiliation: State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province Xiamen, China ; State Key Laboratory of Marine Environmental Science and Key Laboratory of MOE for Coast and Wetland Ecosystems, School of Life Sciences, Xiamen University Xiamen, China ; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources Xiamen, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yuan
authors.affiliation: State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province Xiamen, China ; State Key Laboratory of Marine Environmental Science and Key Laboratory of MOE for Coast and Wetland Ecosystems, School of Life Sciences, Xiamen University Xiamen, China ; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources Xiamen, China.
authors.forename: Qiliang
authors.initials: Q
authors.lastname: Lai
authors.affiliation: State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province Xiamen, China ; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources Xiamen, China.
authors.forename: Fengqin
authors.initials: F
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Marine Environmental Science and Key Laboratory of MOE for Coast and Wetland Ecosystems, School of Life Sciences, Xiamen University Xiamen, China.
authors.forename: Tianling
authors.initials: T
authors.lastname: Zheng
authors.affiliation: State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, Key Laboratory of Marine Genetic Resources of Fujian Province Xiamen, China ; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources Xiamen, China.
authors.forename: Zongze
authors.initials: Z
authors.lastname: Shao
keywords: PAHs; Southwest Indian Ridge; bacterial biodiversity; biodegradation; deep-sea water column; pelagic ocean