Anaerobic dehalogenating bacterial communities in marine sediments and their potential for bioremediation of polluted sediment
Applicants (UK, EU and international) capable of self-funding or with scholarship are welcome to apply.
Primary Supervisor: Prof Andy Weightman
Secondary Supervisors: Dr Julian Marchesi (BIOSI), Prof John Parkes (EARTH), Dr Henrik Sass (EARTH)
Microbes play the central role in global recycling of carbon and other elements. The bioremediation of polluted environments depends upon their abilities to degrade toxic pollutants in situ. However, understanding of these biological and biogeochemical processes in situ is relatively poor, which limits our ability to exploit microbial communities for bioremediation. Since >90% of bacteria in the biosphere cannot be cultivated in the laboratory, molecular biological approaches are needed to explore the diversity of microbial communities in natural and polluted environments.
This project will be to focus on a group of bacteria that produced reductive dehalogenase enzymes are able to dechlorinate compounds such as trichloroethylene (TCE) and chlorobenzenes and utilise them as electron acceptors in an anaerobic process known as dehalorespiration. The overall aim will be to analyse molecular genetic markers, such as 16S rRNA and dehalorespiration genes (i.e. conserved genes encoding dehalogenases and other enzymes involved in dehalorespiration) from contaminated and uncontaminated sediment, and to investigate the relationship between the diversity of dehalorespiring bacteria, their dehalogenases and biodegradation of chlorinated compounds in the an estuarine sedimentary system.
Samples of sediment from sites on the Severn Estuary along a gradient of pollution will undergo both geochemical and molecular microbiological analysis to explore how differences between the dehalorespiring bacteria at different sites are associated with biodegradation of chlorinated compounds in situ. Laboratory based experiments will also be conducted with sediment slurries incubated under anaerobic conditions to manipulate the microbial community and dehalorespiration activities. Metagenomic analysis of selected samples will also be undertaken to obtain a more complete picture of the communities involved and to explore strategies (e.g. biostimulation, bioaugmentation) for bioremediation of contaminated sediment.