- Exciting opportunity to contribute to tackling the major environmental problem of balancing the N-cycle and mitigating aquatic nutrient pollution through enhanced N2 production.
- Working with a major UK water company (Severn Trent) in the development and implementation of the BEST ANAMMOX reactor.
- Systems-level mathematical modelling of the BEST ANAMMOX reactor.
The nitrogen (N) cycle is one of the most important and intricate biogeochemical cycles that controls key nutrient supplies for all life forms on Earth. Anthropogenic activities have impacted the N-cycle to such an extent that its proper management has been described as one of the grand engineering challenges of the 21st century by the US National Academy of Engineering. Despite being abundant in the atmosphere, nitrogen is not readily available to living systems due to its inert nature. Living systems, in which nitrogen is the backbone of DNA and amino acids, obtain this vital element from foods, where atmospheric nitrogen gas is fixed as a nutrient by plants. Subsequently, the cycle is closed by the return of fixed nitrogen compounds to the atmosphere as nitrogen gas (N2) through microbial activities.
The imbalance in the N-cycle has been created by human activities such as excessive nitrogen fixation through industrial production of nitrogen-rich fertilisers, which far exceed the return of N2 gas to the atmosphere by microbial activities. Moreover, the accumulation of fixed nitrogen compounds in the environment, resulting from the excessive use and runoff of nitrogen-rich fertiliser from agricultural land, contributes to nutrient pollution of waterbodies in the form of algal blooms, red tides, and deep-water anoxic dead zones (Figure 1). Thus, enhancing microbial activities to convert fixed nitrogen compounds into N2 can provide a sustainable solution to both the management of the N-cycle and fixed nitrogen pollution. Anaerobic ammonium oxidation (ANAMMOX), mediated by a group of strictly anaerobic and electroactive bacteria, is a novel microbial metabolic process that converts fixed nitrogen compounds into inert N2 gas. However, slow growth of these bacteria is a major impediment for scaling up and industrial implementation of the ANAMMOX process.
This multidisciplinary project aims to develop a bioelectrochemical system (BEST)-based ANAMMOX reactor (Figure 1) for the rapid production of N2 gases by oxidising fixed nitrogen compounds with electric current; thereby, simultaneously balancing the N-cycle and mitigating anthropogenic nitrogen pollution, and thus has great and exciting potential as part of the solution to one of our most pressing environmental problems.
Figure 1. Left panel: Schematic of the BEST ANAMMOX reactor. Right panel: Excessive algal growth is a common result of aquatic eutrophication (Lough Neagh, Northern Ireland).
- Climate and Environmental Sustainability
- Organisms and Ecosystems
Both computational and experimental approaches in systems biology, bioinformatics, electrochemistry, and anaerobic microbiology will be applied to achieve the project goal. ANAMMOX bacteria-enriched cultures will be developed from Severn Trent wastewater treatment sludge using anaerobic microbiology techniques. After optimising these cultures in the lab, the BEST ANAMMOX reactor will be developed using these cultures in an electrochemical cell (Figure 1). The cultures will be sequenced at the NERC Environmental Omics facility (NEOF) in Sheffield. Then a detailed, systems-level mathematical model of ANAMMOX bacteria will be developed using their genome sequences, biochemical, and physiological information. This model will be integrated with the mathematical model of a bioelectrochemical system to develop a Digital Twin (DT) of the BEST ANAMMOX reactor. This DT will be used to identify optimum reactor operating conditions and novel strategies to accelerate the growth of ANAMMOX bacteria for enhanced fixed nitrogen removal and N2 gas production.
Training and skills
Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.
The successful applicant will have a unique opportunity to learn and master a variety of cutting-edge computational and experimental tools and techniques in bioinformatics, systems biology, anaerobic microbiology, and electrochemistry during this project. The student will gain hands-on training on how to use various bioinformatics and mathematical modelling tools, how to apply anaerobic microbiology techniques to culture and maintain anaerobic microorganisms, as well as to conduct experiments with electrochemical cells. Finally, there will be excellent opportunity for the student to gain practical work experience by working with our industrial partner, Severn Trent Water.
Partners and collaboration
Severn Trent (ST) will be acting as a project partner for the BEST N2 project. ST will provide sludge from regional wastewater treatment plants, and this sludge will be used to develop ANAMMOX-enriched bacterial cultures for developing the BEST ANAMMOX reactor. ST will also provide hands-on professional training opportunities for the PhD student to learn the technical details of a wastewater treatment facility. ST is one of the 10 largest regulated water and wastewater businesses in England and Wales, providing high quality services to more than 4.5 million households and businesses in the Midlands and Wales. ST is also a national leader in university – industry collaboration with a long history of project and strategic relationships with the UK’s top academic establishments.
Further details on how to contact the supervisor for this project and how to apply for this project can be found here:
To apply to this project:
- You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024.
- You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities.
- Please submit your application and complete the host institution application process via: https://www.lboro.ac.uk/study/postgraduate/apply/research-applications/ The CENTA application form 2024 and CV can be uploaded at Section 10 “Supporting Documents” of the online portal. Under Section 4 “Programme Selection” the proposed study centre is Central England NERC Training Alliance. Please quote CENTA 2024-LU8 when completing the application form.
- For further enquiries about the application process, please contact the School of Social Sciences & Humanities ([email protected]).
Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024.
Develop ANAMMOX-enriched bacterial cultures and the BEST ANAMMOX reactor, together with the optimum growth and media conditions for the cultures, working closely with Severn Trent.
The development of the detailed mathematical model of ANAMMOX bacteria metabolism, together with the digital twin (DT) of the BEST ANAMMOX reactor and their validation will be achieved in year 2.
The DT of the BEST ANAMMOX reactor will be used to develop novel strategies for accelerating the growth of ANAMMOX-enriched cultures in the BEST reactor, and these strategies will be implemented using the optimised BEST ANAMMOX reactor in year 3 to enhance N2 gas production from fixed nitrogen compounds.
Grand Challenges for Engineers (2023), US National Academy of Engineers. Available at: http://www.engineeringchallenges.org/9132.aspx.
Heirendt, L. et al. (2019) Creation and analysis of biochemical constraint-based models using the COBRA Toolbox v.3.0, Nature Protocols. Available at: https://doi.org/10.1038/s41596-018-0098-2.
Kartal, B. et al. (2011) Molecular mechanism of anaerobic ammonium oxidation, Nature, 479, 127–130. Available at: https://doi.org/10.1038/nature10453.
Kartal, B. et al. (2012) Anammox—Growth Physiology, Cell Biology, and Metabolism, in Advances in Microbial Physiology, 211–262. Available at: https://doi.org/10.1016/B978-0-12-398264-3.00003-6.
Lehnert, N. et al. (2018) Reversing nitrogen fixation, Nature Reviews Chemistry, 2, 278–289. Available at: https://doi.org/10.1038/s41570-018-0041-7.
Rittmann, B.E. and McCarty, P.L. (2020) Microbial Electrochemical Cells in Environmental Biotechnology: Principles and Applications, Chapter B3, 2nd edn, McGraw-Hill Education.
Shaw, D.R. et al. (2020) Extracellular electron transfer-dependent anaerobic oxidation of ammonium by anammox bacteria, Nature Communications, 11, 2058. Available at: https://doi.org/10.1038/s41467-020-16016-y.