Opportunities for synergistic optimization of hydrogen production in microbial electrolysis cells via low-intensity magnetic fields

Applying magnetic fields (MFs) to bioreactors is an emerging technology that seems to have promising opportunities, especially for wastewater treatment. Recent reports show that MFs could enhance the performance of biological treatment processes for various pollutants, including organic matter, nitrogen, and toxic compounds like antibiotics and dyes. This enhancement is often achieved using low-intensity static magnetic fields (L-MFs <100 mT)), typically below 100 mT, which have been shown to stimulate microbial activity, accelerate cell proliferation, and improve enzymatic reaction rates. It is reported that L-MFs can shorten the start-up time for treatment systems by imposing a strong selection pressure that rapidly enriches specific functional microorganisms, such as ammonia-oxidizing bacteria (AOB) and denitrifiers. Moreover, MFs can help microorganisms adapt to and resist harsh environments, such as low temperatures, high salinity, and the presence of toxic pollutants. The application of MFs has been shown to increase the removal rates of organic matter total nitrogen, and specific toxins. Finally, MFs offer the potential to boost the microbial production of valuable resources from wastewater, such as hydrogen, biomethane, lipids, and pigments.

The research to be conducted at UAB aims to start a research line in this field combining the previous background knowledge of two different research groups (GENOCOV – Prof. Albert Guisasola and Physics Department – Carles Navau). Particularly, this thesis will focus in the interactions of L-MFs and bioelectrochemical systems. Microbial Electrolysis Cells (MECs) represent a promising technology for sustainable hydrogen production and wastewater treatment. Their efficiency hinges on the performance of electrochemically active bacteria (EABs) biofilms on the anode. This PhD project will investigate the synergistic application of L-MFs to significantly enhance MEC performance. The project builds upon the work of Park et al. (2025), who demonstrated a 1.8-fold increase in H₂ production by combining a 150 mT MF with magnetic media.

Key objectives of the thesis:

1. Determine the optimal L-MF intensity range and conditions to maximize the growth of key EABs in MECs.
2. Evaluate the synergy between optimized L-MFs and media conditions to promote the formation of a robust electroactive biofilm thereby improving system stability and resilience against harsh conditions like anolyte wash-out.
3. Elucidate the underlying mechanisms: how L-MFs modulate gene expression, membrane transport, and free radical recombination within the EABs’ electron transfer chain.

Based on the proposed project, a candidate researcher would need a combination of
skills in environmental engineering, microbiology, electrochemistry, and data analysis.

The candidate will be guided in all the fields, but some previous experience/knowledge is always valuable. Moreover, as all the PhD students, communication soft skills, ability for team work, methodological rigor, critical thinking, problem-solving and interdisciplinary mindset.

GENOCOV stands for Group of Biological Treatment and Valorization of Liquid and Gaseous Effluents, Removal of Nutrients, Odors and Volatile Organic Compounds. The group is a research group from the Chemical Engineering Department at the Universitat Autònoma de Barcelona.

GENOCOV, whose principal investigator is Prof. Francisco Javier Lafuente, has been active over the last 25 years in understanding the biological processes for the treatment of urban and industrial water and gaseous effluents, with special emphasis on monitoring, modelling and control of such complex biological systems. The quality of the research group can be measured at first sight through several quality indices such as several EU projects and projects funded by the Spanish Government. With respect to publications, in the last 5 years the group has more than 70 peer-reviewed international journals publications as well as an important participation in international conferences. The group consists nowadays of seven senior researchers: Francisco Javier Lafuente Javier Sancho (professor and head of the group), Juan Antonio Baeza Labat, Julian Carrera Muyo, David Gabriel Buguña, Albert Guisasola Canudas, Julio Perez Cañestro, María Eugenia Suárez Ojeda, in addition to around 20 active researchers (including postdocs, PhD students and lab technicians).

In parallel, at the research group SIMMAS, of the physics department, we are devoted on the design, theoretical description, and modelling at all scales, from nano- to macroscopic systems. Our main focuses up to now have been the study of the micromagnetic structures on ferromagnets, superconductivity, and magnetic levitation. We simulate a variety of systems with optimized magnetic performance, including nanowires, lithographically patterned microand nano-objects, thin films, etc.