Degradation of Haloaromatic Compounds by Indigenous Sediment Microflora: Biochemistry and Molecular Ecology

摘要

This study examined microbial communities in biofilms lining marine infaunal burrows with particular focus on marine bacteria able to degrade chlorinated aromatic compounds. These biofilms contain a diverse and abundant microbiota, occurring as single cells and in microcolonial formations. The majority of these organisms are potentially active. The burrow biofilm microbiota includes bacteria able to remove halogen atoms from the aromatic ring of haloaromatic compounds. At least some of these bacteria are amenable to isolation and can be cultivated in the laboratory. Reductively dechlorinating bacteria were enriched from burrows produced by both haloaromatic producing and non-producing marine infauna. It is clear from these results that marine dechlorinating bacteria are common in infaunal burrow structures relative to bulk sediments. Two isolates able to debrominate bromophenols were characterized and identified as novel strains of Propionigenium maris. Microscopic examination also revealed the potential for interspecific interactions among dehalogenating bacteria and other types of organisms. These interactions may include consortial metabolism of chloroaromatics. The study revealed and characterized an important and previously unrecognized niche for reductively dehalogenating bacteria in marine sediments. Infaunal burrow structures provide a source for new organisms with potential application in bioremediation processes.