Research Projects

The transition to a biofuel economy is crucial for a sustainable future, but the recalcitrant nature of cellulosic biomass limits its industrial utilization. Lytic polysaccharide monooxygenases (LPMO) are powerful redox enzymes that degrade these biopolymers by cleaving glycosidic linkages of cellulose chains. However, their industrial utilization is hindered by unclear catalytic action and substrate insolubility. A proposal is made to develop bioinspired copper complexes that can efficiently catalyze biomass oxidation and serve as a substitute for the LPMO enzyme. The enzyme activity begins with the one-electron reduction of active site Cu(II) to Cu(I), which binds to the substrate, cellulose. The reduced state binds with oxygen to form a Cu(II)-superoxide [Cu(II)O₂]+ species, which can give rise to other Cu-oxygen intermediates such as Cu(II)-OOH, Cu(II)-oxyl, and Cu(III)-OH. The Cu-oxyl species is found to be the most potent oxidant, but only observed in the gas phase. Terminal Cu-oxygen intermediates, such as Cu(II)-oxyl and its protonated form Cu(III)-OH, can be considered potential candidates for scissile strong C-H bonds. The synthesized ligands and Cu(II) complexes will be characterized using modern analytical techniques and redox properties studied. The study will initially use p-nitrophenyl-β-D-glucopyranoside as a model substrate, and eventually extend to natural substrates like cellulose and chitin. Trapping the Cu-oxygen intermediate will help in further understanding the catalytic mechanism and boost biofuel utilization.