Discovery and industrial application of lytic polysaccharide mono-oxygenases

The recent discovery of the copper dependent lytic polysaccharide monooxygenases (LPMOs) has opened the door to a vast area of research within several fields. LPMOs are characterised by an N-terminal histidine residue which together with an internal Histidine and a Tyrosine residues coordinates a single copper atom in a histidine brace. The mechanism by which oxygen binds to the reduced copper atom has recently been reported. In solution and in the absence of cellulose, oxygen is rapidly released in the form of superoxide. These enzymes are found wide spread in both fungal and bacterial kingdoms and the range of action of LPMOs remains to be elucidated. The biotech company Novozymes holds patents on the usefulness of these enzymes for the conversion of steam pretreated plant residues such as straw to free sugars that predates the correct classification of LPMOS. The striking synergistic effect of fungal LPMOs when combined with canonical cellulases was discovered when fractions of fungal secretomes were evaluated in industrially relevant active assays. Today, LPMOs play a central part in the Cellic CTec enzyme products and is as such used for industrial production of lignocellulosic ethanol on several full-scale factories around the globe. Judged by the mere abundance of LPMOs expressed by microbes involved in the decomposition of organic matter, the importance of LPMOs in the natural carbon-cycle is predicted to be significant. A further aspect of LPMO research is that these enzymes are predicted to have a role in pathology of infectious disease such as Listeria and may thus become relevant for the medical field