Controlled depolymerization of cellulose by light-driven lytic polysaccharide oxygenases.

Bastien Bissaro, Eirik Kommedal, Åsmund K Røhr, Vincent G H Eijsink

Nature communications 2020 Feb 14

filter terms:

Lytic polysaccharide (mono)oxygenases (LPMOs) perform oxidative cleavage of polysaccharides, and are key enzymes in biomass processing and the global carbon cycle. It has been shown that LPMO reactions may be driven by light, using photosynthetic pigments or photocatalysts, but the mechanism behind this highly attractive catalytic route remains unknown. Here, prompted by the discovery that LPMOs catalyze a peroxygenase reaction more efficiently than a monooxygenase reaction, we revisit these light-driven systems, using an LPMO from Streptomyces coelicolor (ScAA10C) as model cellulolytic enzyme. By using coupled enzymatic assays, we show that H2O2 is produced and necessary for efficient light-driven activity of ScAA10C. Importantly, this activity is achieved without addition of reducing agents and proportional to the light intensity. Overall, the results highlight the importance of controlling fluxes of reactive oxygen species in LPMO reactions and demonstrate the feasibility of light-driven, tunable enzymatic peroxygenation to degrade recalcitrant polysaccharides.

Citation

Bastien Bissaro, Eirik Kommedal, Åsmund K Røhr, Vincent G H Eijsink. Controlled depolymerization of cellulose by light-driven lytic polysaccharide oxygenases. Nature communications. 2020 Feb 14;11(1):890