Discovery of the combined oxidative cleavage of plant xylan and cellulose by a new fungal polysaccharide monooxygenase

Now, for the first time, we demonstrate the activity of a lytic polysaccharide monooxygenase (MtLPMO9A) that shows oxidative cleavage of xylan in addition to cellulose. The ability of MtLPMO9A to cleave these rigid regions provides a new paradigm in the understanding of the degradation of xylan-coated cellulose. In addition, MtLPMO9A acts in strong synergism with endoglucanase I. The mode of action of MtLPMO9A is considered to be important for loosening the rigid xylan-cellulose polysaccharide matrix in plant biomass, enabling increased accessibility to the matrix for hydrolytic enzymes. This discovery provides new insights into how to boost plant biomass degradation by enzyme cocktails for biorefinery applications.