"Amorphogenesis": A Key to Improving Enzymatic Hydrolysis of Cellulosic Biomass

Enzymatic hydrolysis (sometimes called "enzymatic saccharification) is a pretreatment method for breaking-down (i.e., "hydrolyzing") the cellulose molecules in cellulosic-biomass feedstocks, into their component simple sugars (glucose). The glucose is subsequently fermented to biofuel-grade "cellulose-ethanol". A class of enzymes, called "cellulases", is applied to achieve enzymatic hydrolysis. The effectiveness of cellulases is usually limited by the inaccessibility of a large portion of cellulose molecules that lie "buried within the highly ordered and tightly packed fibrillar architecture of the cellulose microfibrils". The enzymes cannot attack these inaccessible portions.


The initial stage in the enzymatic hydrolysis of cellulose is called "amorphogenesis", and it is usually characterized by "fiber swelling and fragmentation of cellulose aggregations into short fibers". Amorphogenesis is desirable for increasing the accessibility of cellulose to enzymatic attack. Certain types of proteins have been found to be good "amorphogenesis-inducing agents"; they disrupt the tight cellulose packing in a non-hydrolytic manner and enhance cellulose accessibility. Scientists from the Faculty of Forestry, University of British Columbia (Canada), recently published a review paper on amorphogenesis. They briefly outlined the the structural arrangement of cellulose in the fibrillar architecture, and an overview of "amorphogenesis-inducing agents and their interactions with cellulose". The paper appears in the open access journal, Biotechnology for Biofuels (
http://www.biotechnologyforbiofuels.com/content/pdf/1754-6834-3-4.pdf
(provisional pdf during time of access).

Source : CropsUpdate