Project Outline

Lignocellulosic plant biomass is the most abundant waste product generated by society, agriculture and industry. By 2025, global cities will generate approximately 2.2 billion tonnes of solid waste biomass per year, with significant impacts upon health and the economy at both local and global scales. Natural communities of microorganisms convert waste biomass to methane-rich biogas that can be used as a sustainable and renewable green-energy source to generate electricity, heat and power, and biomethane for injection into the national gas grid and production of transport fuels. Anaerobic digestion (AD) plants and landfill sites are engineered environments where these microbial processes are harnessed for waste decomposition and biogas production. The EU is the largest global producer of biogas from biomass, with over 17,000 AD plants, and consequently, the microbiological conversion of solid waste residues to biogas in AD plants and landfill sites presents an unprecedented opportunity to leverage key enabling technologies for a sustainable bio-based economy for green-energy production. In turn, conversion of waste biomass to biomethane will mitigate the escalating environmental and social impacts of waste residues. However, substrate specificity and enzymatic hydrolysis of recalcitrant organic biomass is a major bottleneck to the efficiency of industrial bioconversion processes. Natural microorganisms found in landfill sites represent an unexplored repository of biomass-degrading enzyme diversity with the potential to enhance existing industrial biomass-conversion processes. Engineering biomass-degrading microbiomes is a new research frontier with many novel applications, including bioaugmentation and optimisation of biomass conversion in AD and landfill systems towards an enhanced bio-based economy for waste management, environmental protection, and sustainable intensification of renewable energy generation.

Aim

The aim of this project is to design and test synthetic microbial communities (SynComs) comprising anaerobic landfill microbiota for enhanced conversion of waste feedstocks into biogas.

Methods and Research Objectives

The candidate will utilise a range of methods (anaerobic microbial culture, synthetic community design and assembly, operate batch and continuous culture reactors, biogas analysis, quantitative PCR, 16S rRNA gene community profiling, metagenomics and computational analyses) to address the following research objectives:

1. Test the effects of inoculum size and mode of delivery on the establishment, stability and persistence of SynComs in anaerobic digestion processes.

2. Design and test SynComs for the bioconversion of diverse feedstock types.

3. Optimise minimal SynComs for waste biomass conversion to biogas.

References

Ransom-Jones, E., McCarthy, AJ., Haldenby, S., Doonan, J. & McDonald, JE. (2017) Lignocellulose-Degrading Microbial Communities in Landfill Sites Represent a Repository of Unexplored Biomass- Degrading Diversity. mSphere. 2, 4, e00300

Lawson, C.E., Harcombe, W.R., Hatzenpichler, R. et al. Common principles and best practices for engineering microbiomes. Nat Rev Microbiol 17, 725–741 (2019). https://doi.org/10.1038/s41579-019-0255-9

Techniques

Anaerobic microbial cultivation, testing synthetic microbial communities in batch and continuous culture, biogas analysis, DNA extraction, PCR, 16S rRNA gene community profiling, metagenomics/genomics, computational analysis of DNA sequencing data.