A novel microaerobic bioreactor to enhance Magnetotactic Bacteria growth and magnetosome production for application as biosorbents for metal recovery from electronic waste

Annually, the world generates over 62 million tonnes of electronic waste (e-waste), which contains metals (e.g. lead, mercury, cadmium), which, if not properly managed, can leach into the environment, contaminating soil, water, and air. This situation poses a significant risk to human health and ecosystems, necessitating innovative recycling measures. So far, hydrometallurgical processes for metal recovery have made strides in addressing these issues. However, challenges such as their sustainability approaches, storage capacity, high energy costs, and scalability are problematic, leading to an urgent need for new solutions. The use of magnetotactic bacteria (MTB) represents an alternative low-carbon route for metal recovery, as they can uptake and store large amounts of metals in the form of magnetosomes, (magnetic nanoparticles that can be doped with a variety of metals for superior biotechnology applications) and biosorb a wide range of metals on the bacterial membrane. However, MTB are typically cultivated using off-the-shelf bioreactors as a one-fit-all system, with sparging hydrodynamics significantly limiting microbial growth as they require tightly controlled microaerobic conditions. Therefore, this interdisciplinary project aims to develop, optimize and scale up a sustainable biomanufacturing strategy (via enhancing production performance) for MTB growth using e-waste with a novel bioreactor design. This aim successfully addresses a significant environmental problem with a low-energy, sustainable process. Overall, the developed technology will create industrial potential for its utilisation in other applicable processes, such as the health sector. This project will have a great social and economic impact in Europe by contributing to reaching Net Zero and the Green Deal targets by 2050 while advancing bionanotechnologies. It also has the potential to create new business models and technology development while promoting circular bioeconomy principles.