Microbial community dynamics

We work to understand how changes in operating conditions affect the microbiomes at the centre of the anaerobic digestion (AD) process. This understanding will provide routes for better harnessing AD processes to improve effective recycling of resources from waste.

Microbes are the engine at the heart of AD, converting the available resources (wastes) into "useful" products in the absence of oxygen. The engineered systems used for wastewater treatment employ naturally-occurring microbial communities, similar to the microbiomes found in human and animal guts.

While each species within a microbial community can be considered as a clockwork mechanism - integrating signals from its environment to generate a predictable response - the community complexity and heterogeneous environment result in emergent behaviours. We have shown these behaviours are reproducible in AD systems from lab to process scale.

We are building a functional classification of AD microbes that will provide a mechanistic basis for assembling high-performing microbial communities that are resilient to changes in feedstock and operating conditions. This will allow communities to be tailored to improve resource recovery and ultimately allow us to generate "designer" products from wastes.

"As well as housing unique facilities, CEAD brings together the technical knowledge and expertise to explore anaerobic microbiology from numerous angles."

Professor James Chong, Research Lead.

Activities and partnerships

Biomethanisation

With the Universities of Southampton and Sheffield and United Utilities, we determined how the methanogenic community adapted to the addition of hydrogen to lab scale AD systems operated on synthetic wastewater containing different carbon concentrations.

The presence of additional substrate resulted in a change in the methanogenic species and an increase in the proportion of methanogens, leading to biogas that was more than 95% methane.

Feedstock changes

In collaboration with Thames Water, we extracted and analysed the microbiomes of two wastewater AD reactors that were intensively sampled during an operational change.

The digesters were moved from conventional sludge to material that was subjected to a high temperature pre-treatment. Similar large scale changes were observed for both digesters, as numerous species were replaced by organisms that were better suited to the altered feedstock.

Community dissection

We are developing and automating a pipeline for the dissection of anaerobic microbial communities.

By functionally characterising the species we isolate, we will map how various "functional guilds" assemble to provide a functioning AD community and how different guilds may be required to effectively treat feedstock of different compositions.