Nature of Cellulosic Material

Abstract

The hydroysis of native lignocellulosics, especially that catalyzed by enzyme, is a slow process. The heterogeneous degradation of lignocellulosics is governed primarily by their structural features since (1) cellulose present in biomass possesses a highly resistant crystalline structure, (2) lignin surrounding the cellulose forms a physical barrier, and (3) the reactive sites available are limited. The cellulose present in lignoeellulosics is composed of crystalline and amorphous components [7]. The amorphous component is usually more reactive than the crystalline component, and thus any means that will increase the amorphous content will enhance the hydrolysis rate [12,16,17, 50]. The presence of lignin forms a physical barrier for attack by either enzyme or acid molecules; therefore, treatments causing disruption of the lignin seal will increase the accessibility of cellulose to enzyme or acid molecules and eventually its hydrolysis rate. The limitation of available reactive sites stems from the fact that the average size of the capillaries in biomass is too small to allow the entry of reactive molecules, especially the large enzyme molecules.