Cellulolytic Enzyme Production and Enzymatic Hydrolysis for Second-Generation Bioethanol Production - Biotechnology in China: Biofuels and Bioenergy - page 7

Fig. 3 Model of synergistic effect of the cellulose-binding module (CBM; or cellulose-binding
domain) and the catalytic domain (CD) in CBH I
accelerates the binding of CBH I to crystalline cellulose. This results in an increase
in local cellulase concentration on the cellulose surface [ 28 , 29 , 31 - 33 ].
As shown in Fig. 3 , the binding of the CBD to crystalline cellulose is
hypothesized to result in a change in the spatial coordination of the hydroxyl
groups on the surface of the polysaccharide chain and, subsequently, the hydrogen
bond network; this results in the ''peeling'' of the cellulose chain from the crys-
talline structure, the disruption of the surface of this structure, and the decrease
in the regional DP [ 18 , 29 ]. This interaction between the CBD and crystalline
cellulose was observed using purified CBD from EG III of T. reesei, which is
homologous to the CBD from CBH I. The addition of purified CBD to cellulose
decreases the number of hydrogen bonds by 17.0% and the crystalline index by
16.5% [ 34 ]. In another report, the turbidity of cellulose CF11 increased by 128.9%