In contrast to O2, H2O2 as the
cosubstrate for lytic polysaccharide monooxygenases (LPMOs) exhibits
great advantages in industrial settings for cellulose degradation.
However, H2O2-driven LPMO reactions from natural
microorganisms have not been fully explored and understood. Herein,
secretome analysis unraveled the H2O2-driven
LPMO reaction in the efficient lignocellulose-degrading fungus Irpex lacteus, including LPMOs with different oxidative
regioselectivities and various H2O2-generating
oxidases. Biochemical characterization of H2O2-driven LPMO catalysis showed orders of magnitude improvement in
catalytic efficiency compared to that of O2-driven LPMO
catalysis for cellulose degradation. Significantly, H2O2 tolerance of LPMO catalysis in I. lacteus was an order of magnitude higher than that in other filamentous
fungi. In addition, natural reductants, gallic acid, in particular,
presented in lignocellulosic biomass could sufficiently maintain LPMO
catalytic reactions. Moreover, the H2O2-driven
LPMO catalysis exhibited synergy with canonical endoglucanases for
efficient cellulose degradation. Taken together, these findings demonstrate
the great application potential of the H2O2-driven
LPMO catalysis for upgrading cellulase cocktails to further improve
cellulose degradation efficiency.