Lytic Polysaccharide Monooxygenases in Enzymatic Processing of Lignocellulosic Biomass

The discovery of lytic polysaccharide mono-oxygenases (LPMOs) has revolutionized enzymatic processing of polysaccharides, in particular, recalcitrant insoluble polysaccharides, such as cellulose. These monocopper enzymes display intriguing and unprecedented catalytic chemistry, which make them highly valuable in industrial bioprocessing, but also generate considerable challenges in terms of scientific understanding and optimal implementation. One issue of particular interest is the fact that both molecular oxygen and hydrogen peroxide can drive LPMO reactions. Here, we review recent insights into the catalytic mechanism of LPMOs derived from structural, spectroscopic, and functional studies. We then turn to the question of how one can optimally harness the potential of LPMOs in biomass processing, given the current knowledge of their catalytic mechanism. Finally, we review recent, more applied studies that have addressed the importance of LPMOs in enzymatic conversion of lignocellulosic biomass and discuss how the impact of these powerful enzymes could be improved.