Lytic polysaccharide monooxygenases as global carbon cycle regulators and a lever to the bioeconomy

Cellulose, hemicellulose, and chitin are Earth’s most abundant biopolymers, yet their crystalline structure makes them highly recalcitrant, creating a bottleneck in the global carbon cycle and the bioeconomy. For decades, polysaccharide degradation strategies focussed exclusively on hydrolytic enzymes. This perspective synthesises breakthroughs, highlighting the discovery of lytic polysaccharide monooxygenases and providing a comprehensive framework to evaluate their global function. We chart the scientific evolution of these enzymes into powerful, context-dependent hydrogen peroxide-driven peroxygenases using an oxidative mechanism to disrupt crystalline surfaces. We argue this synergistic oxidative-hydrolytic strategy is nature’s primary solution to the polysaccharide challenge. We propose two hypotheses: first, that lytic polysaccharide monooxygenases are critical gatekeepers of the carbon cycle in terrestrial and marine ecosystems; and second, that their oxidative chemistry can be engineered for broad frontiers, including advanced biorefineries and synthetic polymer degradation. Embracing this oxidative paradigm is essential for ecological understanding and architecting a circular economy. Lytic polysaccharide monooxygenases, reclassified as hydrogen peroxide-driven peroxygenases offer a primary natural solution for breaking down tough biopolymers like cellulose via an oxidative-hydrolytic strategy, playing a critical role in the global carbon cycle.