Rational design of microbial community mixtures for biogas production

Microbial communities play key roles in biotechnologies such as Anaerobic digestion (AD). AD is becoming an increasingly widespread technology for the production of biogas and the management of human and agricultural waste, estimated to contribute up to 7.5% of UK renewable energy supplies by 2020. Despite a good understanding of how performance can be enhanced by the physical engineering of AD reactors and the addition of specific nutrients, much less is known about the powerhouse of ADs - the microbial community itself - and how this can be manipulated to increase the efficiency of biogas production.

We have recently shown that biogas production during AD can be enhanced simply by mixing multiple microbial communities together, resulting in increased gas yields in the order of 10%. Here, we propose to greatly refine this process by identifying particularly productive community combinations, on the basis of where the communities were originally isolated from and a "metabolic fingerprint" showing what the community is consuming and producing. We will determine how the approach can be applied to real-word settings by identifying optimal conditions for the invasion of failing reactors. Finally, we will test the approach in a controlled industrial trial involving 12 AD reactors, half of which will be invaded with while the other half will be left as controls.

The work, conducted by experts at the Universities of Exeter and York, will have the financial and logistical support of Amur Energy - a leading AD consultant in the UK. Their unrivalled access to the UK's AD community and their extensive fleet of agricultural lorries operated by their parent company, AB Agri, make the approach both commercially viable and of huge environmental benefit. In addition to the clear benefits for biogas production and waste management, the work will greatly improve our understanding of the consequences of community mixing (a process that occurs all the time in nature) in general, and have potential to improve the efficiency of other processes involving microbial communities, such as sewage treatment and the detoxification of contaminated water and soil.

We have recently shown that biogas production can be enhanced through mixing multiple microbial communities together. We propose to improve this process and assess its practical application in industrial settings. We will combine high throughput laboratory experiments, genetic and metabolomic profiling and modelling to identify community combinations and invasion conditions that will enhance reactor performance. We will use this information to conduct an industrial-scale trial, the results of which will be used to assess and refine the predictive power of lab-scale measures for improving the efficiency of industrial ADs. In addition to the clear applied benefits, the results will provide fundamental and novel insights into the dynamics of microbial "community coalescence", which are likely to have relevance for the enhancement of other biotechnological, remediation and agricultural processes

The project seeks to enhance the efficiency of methane production from anaerobic digestion (AD) in industrial contexts through bio-augmentation. The work will have significant direct impact for the AD industry. Impact will primarily be realised through our industrial partner, Amur, who offer services to improve the efficiency of AD throughout the UK. Amur has been closely engaged in the co-design of the proposal and exploitation of the results thereof. They will conduct a controlled, replicated trial (objective 4) and offer advice and the bio-augmentation service to their clients. To this end, we will hold regular workshops in partnership with Amur to communicate our findings to participants in the industrial trial and the wider customer base and identify IP assets and products for exploitation. Most impact will occur towards the end of the grant, when the industrial trial is complete, yet Amur, and where relevant their client base, will provide input and guidance into the earlier experimental phases of the project. There is likely to be Intellectual Property (IP) associated with the project, notably the ability to select synergistic community combinations, and identifying and protecting this will be crucial for the application of the more refined methods. We will establish IP protection (by agreement with all partners) if the lab-based results are promising. The general approach could improve a range of biotechnologies involving microbial communities (e.g. bioremediation of contaminated soils and water), hence we will communicate the results through a broader stakeholder workshop involving existing contacts (notably water industries). Finally, we will communicate the work to the general public via a range of established activities through the Universities of Exeter and York.