New class of enzymes can degrade biomass more efficiently

Natural carbohydrate polymers such as starch, cellulose, and chitin provide renewable alternatives to fossil fuels as a source for fuels and materials. As such, there is considerable interest in their conversion for industrial purposes.

In a recent review in the journal Chemical Reviews, researchers from the Department of Molecular Sciences and colleagues from Stanford University and DuPont Industrial Biosciences describe what is currently known about oxidative cleavage of carbohydrate polymers, such as cellulose, chitin and starch.

A new class of enzymes

This reaction, special of its kind, is catalyzed by a relatively new class of enzymes called lytic polysaccharide monooxygenases (LPMOs). These LPMOs are copper-dependent enzymes which together with classical glycoside hydrolases participate in the degradation of recalcitrant carbohydrate polymers.

Their activity and structural underpinnings provide insights into biological mechanisms of polysaccharide degradation. LPMOs break polysaccharide chains in an oxygen- and electron dependent process, apparently without the need for prior de-crystallization of the crystalline substrate.

Applications for the industry

The use of this new class of oxidative enzymes can contribute to a reduced dosage of enzymatic cocktails for the industrial degradation of lignocellulosic biomass substrates. These and other features of LPMOs are discussed in more detail in the review paper.