Across the world, communities face linked challenges: chemical contamination of water by metals such as arsenic, lead, cadmium, and zinc [1], the energy and cost burden of producing critical minerals [3], and growing waste streams that demand better recovery of nonferrous metals [4]. Metlock proposes a biology-enabled approach: using engineered E. coli to selectively capture zinc (Zn²⁺) from dilute waters and process streams so it can be recovered and reused.
Heavy-metal pollution in water arises from both geogenic sources (e.g., arsenic-rich aquifers) and human activities (mining, industry), and metals can also enter water through corrosion of water-contact materials (e.g., galvanized coatings or brass components). WHO notes that inorganic arsenic is among the most significant chemical contaminants of drinking-water globally [1]. For zinc, EPA sets a secondary (aesthetic) drinking-water standard of 5 mg/L to limit taste/appearance issues, underscoring why reducing dissolved Zn in distribution/treatment contexts is desirable [2]. By tuning uptake with inducible control, Metlock is designed to remove excess dissolved zinc in a contained, treatment-plant-compatible module and return the captured metal to productive use.
Mining and mineral processing are energy-intensive. According to CEEC’s 2021 analysis, comminution alone accounts for roughly one-quarter of a typical mine site’s final energy use and may consume up to ~1% of global final energy [3]. Metlock is not a replacement for primary mining, but it can complement it by recovering zinc from low-grade leachates, tailings waters, and industrial effluents under ambient conditions. This technology has the potential to lower energy per kilogram recovered in those dilute contexts. (Like all biological systems, it still requires nutrients and process energy for operation.)
Improving circularity matters. EPA data show significant flows of nonferrous metals in municipal waste, with very high recovery of some (e.g., battery lead), highlighting the opportunity to increase recovery of others [4]. Deploying selective biosorption/uptake modules at landfills, recycling centers, and industrial sites could help divert zinc from disposal while generating a reusable product.
Metlock’s sustainability value is therefore two-fold: first, it protects water quality by reducing dissolved zinc loads where aesthetics and operational performance matter [2] while supporting broader public-health safeguards in areas where metal contamination is a concern [1]; second, it enhances resource efficiency by harvesting a useful metal from dilute, previously uneconomic streams [3][4].
[1] World Health Organization. (2022). Arsenic: Fact sheet. https://www.who.int/news-room/fact-sheets/detail/arsenic
[2] U.S. EPA. (2025). Drinking Water Regulations and Contaminants — National Secondary Drinking Water Regulations (Zinc 5 mg/L). https://www.epa.gov/sdwa/drinking-water-regulations-and-contaminants
[3] Allen, M. (2021). Mining Energy Consumption 2021. CEEC (Coalition for Energy Efficient Comminution). https://www.ceecthefuture.org/resources/mining-energy-consumption-2021
[4] U.S. Environmental Protection Agency. (2024). Other Nonferrous Metals: Material-Specific Data. https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/other-nonferrous-metals-material-specific