Dehalogenation of brominated phenolic compounds by environmental microorganisms

Abstract

Halogenated compounds constitute one of the largest groups of environmental pollutants and are a worldwide issue accumulating readily across even remote environments. Contamination by halogenated flame retardants such as polybrominated diphenyl ether (PBDE) is widespread, including marine and freshwater sediments, soil and human tissue. This has been hypothesised to lead to multiple health issues following exposure such as endocrine disruption and immune system alterations. Despite a recent reduction in use, PBDE containing products will continue to leach into the environment for years. Marine sponges are a natural reservoir of brominated compounds and dehalogenation activities of the associated microbiota have been previously observed. It has been postulated that mechanisms for microbial mediated degradation of halogenated compounds also exist within environmental samples commonly contaminated by PBDEs, for example widespread areas of soil sediment. In order to detect and investigate the dehalogenation capabilities of environmental microorganisms, sediment samples from recycling plants have been used to create microcosms with various PBDE congeners (PBDE 47, 99, 153, 209) added, to establish bacterial communities in the laboratory associated with potential PBDE degradation. Once dehalogenation is detected characterisation of debrominating communities from environmental samples will be performed using microbial community 16S rRNA community profiling and QRTPCR. This will provide valuable insight to bacterial communities associated with haloaromatic degradation and further useful information for potential bioremediation of PBDE contaminated soils and sediments.