Engineering Biology Hub for environmental processing and recovery of metals; from contaminated land to industrial biotechnology in a circular economy

The Engineering Biology Mission Hub for Environmental Processing and Recovery of Metals (ELEMENTAL) aims to address the growing need for critical minerals and metals in clean energy technologies and promote a circular economy. The project brings together specialists from various UK institutions to establish an open knowledge hub focused on bio-extraction and bio-recovery of metals. The hub aims to enhance ongoing projects related to mineral extraction, urban mining, industrial waste, and nuclear waste by leveraging engineering biology tools and approaches. The project emphasizes the importance of sustainable and efficient solutions to tackle environmental challenges associated with metal waste and scarcity. Technologically critical metals, such as rare earth elements (REEs), cobalt, lithium, and indium, pose significant challenges due to their limited availability and the environmental damage caused by their extraction. Recycling these metals is crucial for reducing the demand for primary mining and minimizing environmental impacts.

The hub focuses on targeted approaches such as bioleaching, bioremediation, and biorecovery to address metal waste, REE and radionuclide waste, and metal scarcity. Bioleaching uses microorganisms to recover metals from various sources, while bioremediation employs microorganisms or plants to remove metals from polluted water and land. The project also explores the potential of phytomining, where certain plants naturally accumulate metals and REEs from the soil. The integration of engineering biology, including genetic engineering and synthetic biology, offers opportunities to enhance the capabilities of microorganisms and plants involved in metal recovery processes. By optimizing metal transporters and developing genetic circuits, the project aims to improve metal accumulation, develop biosensors for real-time monitoring, and enhance metal bioremediation and recovery practices.

The project acknowledges challenges related to process optimization, scalability, economic viability, and environmental impact assessments. A multidisciplinary approach will be employed to develop strategies for improved metal recovery and address social, economic, and environmental challenges. The hub will work closely with policymakers and stakeholders to develop policy recommendations and guidelines for the use of engineered organisms in metal remediation within a circular economy framework. The project's objectives will be realized through six work packages focused on bioleaching, biorecovery, industrial biotechnology, biosensors, bioremediation, and scale-up, techno-economic analysis, and life cycle assessment. The hub members possess expertise in synthetic biology, protein design, biogeochemistry, metal transporters, responsible research and innovation, and phytoremediation.

The engineering biology approach within the hub follows a design-build-test cycle to optimize engineered systems for metal recovery applications. Genetic techniques, including massively parallel transposon mutagenesis, will be used to identify genes involved in metal tolerance and develop mutant libraries. Additionally, physical techniques such as EPR spectroscopy, NMR, electron microscopy, and XAS will provide molecular insights into the speciation and interaction of metals with biological systems. By harnessing synthetic biology-based systems and interdisciplinary collaborations, the ELEMENTAL hub aims to revolutionize metal bioremediation and recovery practices, contributing to a cleaner and more sustainable environment.

The grant focuses on using engineering biology to enhance metal extraction and recovery from mining, urban and nuclear waste through engineered biology processes, including microbes and plants. The project includes developing innovations in bioleaching, biorecovery and bioremediation, coupled with underpinning techno economic analyses and lifetime cycle assessments. Bioleaching will be tackled though engineering acidophilic bacteria and cyanogenic bacteria to improve their leaching capabilities for metal extraction. The project will use synthetic biology tools to enhance stress resistance and metabolic pathways in biomining microorganisms. Metallic biorecovery will be targeted though engineering biology approaches that address the biomineralization of metal particles and the production of metal sulfides, as well as engineering cell surfaces and compartments for metal sorption. Reducing metal usage and waste in industrial biotechnology is of major interest to chemical and biotherapeutic companies. The goal is to decrease the level of metals required in cell culture and fermentation processes, which will be achieved through up and down regulation of metal transporters that still optimize growth for product formation. The development of specific and sensitive metal biosensors for detection and response in waste stream is a key objective of the Hub. Engineering biology will be applied to cell biosensors using metal-sensing transcriptional regulators and the development of protein/enzyme-based biosensors. For bioremediation, utilising synthetic biology and gene editing techniques for metal solubilization in the rhizosphere, in planta expression of metal-binding proteins, and engineering ferritins for gold and REE accumulation and sensing will be undertaken. The main experimental approaches undertaken in the Hub will be complemented by undertaking material flow analysis in environmental sources, developing circular economy strategies, and scaling up bioprocesses.