Engineering a polysaccharide monooxygenase for increased thermoactivity

Polysaccharide monooxygenases, or PMOs, are a class of enzymes capable of oxidatively cleaving crystalline cellulose.  PMOs are of great interest due to their ability to dramatically improve the productivity of enzymatic hydrolysis, in which lignocellulosic biomass is depolymerized into sugars.  Such efficiency improvements translate to more cost-competitive biofuels.  As second-generation biofuel processes grow to scale, performing hydrolysis at higher temperatures (~70˚C instead of 50˚C) would improve the process by affording a higher biomass loading and by decreasing the risk of contamination.  Our aim is to alter the thermoactivity of a PMO enzyme, using directed evolution, such that the enzyme will be suitable for high-temperature biomass depolymerization (alongside thermostable hydrolases).  This would represent the first example of PMO engineering, and would facilitate an efficient, high-temperature depolymerization process