Human Practices

As the global demand for critical minerals continues to rise, so does the need for sustainable and environmentally friendly methods of extraction. Traditional mining of resources, such as zinc, often causes disruption in ecosystems, generates toxic waste, and exposes communities to harmful contaminants [1][2]. Furthermore, industries reliant on these resources are facing growing supply chain pressures and environmental scrutiny [3][4]. The goal of the Metlock project is to provide a more sustainable, scalable, and ecologically safe solution to protect our environment and address economic needs.

Instead of waiting for resource scarcity or environmental crises to worsen, this project emphasizes preventative action. The objective is to design a biological system that not only reduces the need for destructive mining practices but also creates a more effective and less intrusive method of bioremediation for contaminated environments [5][6]. This is being accomplished through the genetic engineering of E. coli to express zinc transport proteins under inducible control [7][8][9][10]. The team envisions adapting this approach to toxic metals, such as lead and cadmium, to resolve larger environmental issues. For example, polluted water of the lead belt in southeast Missouri has affected drinking water in numerous counties [11].

Environmental responsibility remains a central value of the project. Engineered microbes, including those developed through Metlock, could pose risks if unintentionally released. To address this, initial experiments are being maintained under strict in vitro conditions, while strategies for biocontainment are being explored for future scaled applications. Additionally, a non-pathogenic strain of E. coli will be used to minimize hazards [7][9]. Within the next five years, the project aims to expand from laboratory scale to environmental, incorporating additional safety measures for larger applications. An inducible system is being developed to toggle activation with AHL induction.

Development of the project begins locally. Consultations have been held with Missouri University of Science and Technology faculty from a broad range of departments, including Biological Sciences, Chemical Engineering, Mining Engineering, Chemistry, and Environmental Sciences. Additional collaboration with experts in Environmental Engineering, industry stakeholders, and community representatives is planned to examine potential investments. The aim is to refine the project into a resource that is efficient for bioremediators, environmental engineers, biomining researchers, other iGEM teams, and municipalities for applications ranging from cleaning water supplies to extracting profitable amounts of metal from ore.

Based on feedback from Mining Engineering depeartment and conference participants, we prioritized four practical design targets: (1) orienting the biology toward dilute zinc streams up to ~1 g/L, (2) aligning Metlock with existing froth-flotation workflows as a bypass/polishing step to improve water quality, (3) moving bench experiments into controlled bioreactor formats to tune residence time, mixing, and oxygen demand, and (4) quantifying uptake capacity and kinetics (e.g., q_max in mg Zn per g dry cell weight and half-saturation parameters) to credibly size units and inform design decisions. This guidance is reflected in our near-term plan: batch and chemostat trials spanning 10–1,000 mg/L Zn, closed-loop mass-balance reporting of zinc removal efficiency, and side-by-side comparisons with incumbent reagents and methods. These priorities will directly inform future computational modeling and currently inform the development of our zinc-transport toolkit (ZnuABC) as we build for integration into industrially relevant contexts [5][7][8][9][10][12].

Further outreach has been pursued on both the university campus and in professional settings. Metlock has been presented to hundreds of students enrolled in biological, ecological, and chemistry courses to increase participation and gather new perspectives for research. In addition, the project was presented at the 5th Annual NSF-funded Critical Minerals Conference held in Rolla, Missouri, in August 2025. During this conference, our team took home 1st place for the conference's NSF poster contest [12]. This resulted in connections with professionals able to provide further guidance, and connections in academia who encouraged us to apply for federal grants. Feedback from these groups will support optimization of the engineered system to address bioremediation and biomining needs simultaneously, while also guiding future research toward industrial biomining and environmental remediation. Input from these experts is essential for ensuring that Metlock not only succeeds scientifically but also meets real-world demands.

Throughout the project, we have stayed true to our commitment to fostering a diverse team. Our group of students are from a variety of personal and academic backgrounds in chemical and biochemical engineering, chemistry, environmental sciences, biological sciences, computer science, computer engineering, and more. Each member brings a unique perspective to further guide this project in being scientifically rigorous and provide input on how to express our system across various modalities. For example, we utilized the strengths of our computer science and engineering members to build a simulation that models the expression of the Anderson Family promoters and our AHL induction model for simulated data collection purposes to develop a computational model that leverages the strength of multiple disciplines on our team. The diverse perspectives of our group have been essential in problem solving, going through the iterative design process, and pivoting the project when needed throughout the design, build, test, and learn phases.

Through Metlock, the team hopes to contribute toward a future where critical mineral supply and environmental responsibility can coexist, reacting to both the crisis of scarcity and mineral pollution. The project strives to maintain environmental responsibility in design, reflect on the values guiding development, and remain responsive to the world beyond the lab in deployment.