3-16: Biophysical characterization of protein/cellulose surface interactions

Abstract

Cellulose is an unbranched, linear homopolymer of glucose units connected by β-1,4 linkages. These linear chains vary in length and often consist of many thousands of units.  Cellulose is the major polysaccharide found in plant biomass, accounting for much of the organic material on the surface of the Earth. Cellulases are enzymes that catalyze the hydrolysis of cellulose into smaller oligosaccharides. Cellulases, or glycoside hydrolases, are categorized into two groups: endoglucanases and exoglucanases, both synergistically catalyze the hydrolytic cleavage of the glycosidic bonds in cellulose to produce cellobiose.  A third group of non-hydrolytic proteins have been proposed to interact at the cellulose surface and are thought to contribute to its efficient degradation by disruption or modification of the surface.  These proteins include CBMs, fibronectins, hydrophobins, and swollenins that are produced by a number of biomass degrading microorganisms.  We are using a number of biophysical characterization techniques to study the interactions of these proteins with the cellulose surfaces.  Presented will be the results of a combination of spectroscopy, microscopy, and thermodynamic techniques that can be used to characterize these complex interactions between proteins and biomass surfaces.