The production and recycling of chemicals and materials that society needs is sometimes challenging and often requires environmentally harsh processes. Enzymatic processes provide a green alternative, but efficient enzymes are not always available. Building on recent breakthroughs in enzymology and computational enzyme design, OxyGreen will develop new copper-based enzymes that can catalyse important chemical reactions under mild conditions, using enzymes called lytic polysaccharide monooxygenases (LPMOs) as a starting point. The natural role of these enzymes is in the breakdown of biomass, for example cellulose in plant material. First, we will redesign the microenvironment around the catalytic copper site of LPMOs to hold small organic molecules in a reactive position, yielding new enzymes for advanced chemical synthesis. Second, we will redesign LPMOs and their appended substrate-binding modules so they can attach to and oxidize plastics, yielding new enzymes for plastic recycling.