been purified from Aspergillus nidulans (Bagga et al. 1990). Two cellobiohydrolases
have been identified in Aspergillus ficuum (Hayashida and Mok 1988) and Aspergillus terreus (Ivanova et al. 1983). Similarly, two immunologically dissimilar
cellobiohydrolases (CBH I and CBH II) were identified in Trichoderma spp. specifically reesei (Kubicek and Pentilla 1998). The organization of native cellulose and
its hydrolysis by different endoglucanases and cellobiohydrolases is demonstrated
schematically in Fig. 3.3. These enzymes operate in a mutualistic approach. The
endoglucanase breaking linear cellulose polymers, generating reducing and
non-reducing ends that, in turn, can be breakdown by exoglucanase. Exoglucanases,
in turn, work to eliminate cellulose and open more internal sites for endoglucanase
binding.
The role of these two enzymes, particularly CBH, is restrained from cellobiose.
The breaking of cellobiose to glucose using β-glucosidase very much decreases this
inhibition and permits continuous cellulase activity. This standard synergism among
exoglucanase and endoglucanase was extended to cover a variety of cellulolytic
fungi (Wood et al. 1995; Wood and McCrae 1996). Still, synergistic interactions
(exo-exo) among isozymic forms of exoglucanase happened in solubilizing crystalline cellulose (Henrissat et al. 1985).
Fig. 3.2 Mechanism of cellulose degradation by cellulase
Fig. 3.3 Efficiency in cooperation of members of cellulase enzyme system
76
M. Subhosh Chandra et al.
have been identified in Aspergillus ficuum (Hayashida and Mok 1988) and Aspergillus terreus (Ivanova et al. 1983). Similarly, two immunologically dissimilar
cellobiohydrolases (CBH I and CBH II) were identified in Trichoderma spp. specifically reesei (Kubicek and Pentilla 1998). The organization of native cellulose and
its hydrolysis by different endoglucanases and cellobiohydrolases is demonstrated
schematically in Fig. 3.3. These enzymes operate in a mutualistic approach. The
endoglucanase breaking linear cellulose polymers, generating reducing and
non-reducing ends that, in turn, can be breakdown by exoglucanase. Exoglucanases,
in turn, work to eliminate cellulose and open more internal sites for endoglucanase
binding.
The role of these two enzymes, particularly CBH, is restrained from cellobiose.
The breaking of cellobiose to glucose using β-glucosidase very much decreases this
inhibition and permits continuous cellulase activity. This standard synergism among
exoglucanase and endoglucanase was extended to cover a variety of cellulolytic
fungi (Wood et al. 1995; Wood and McCrae 1996). Still, synergistic interactions
(exo-exo) among isozymic forms of exoglucanase happened in solubilizing crystalline cellulose (Henrissat et al. 1985).
Fig. 3.2 Mechanism of cellulose degradation by cellulase
Fig. 3.3 Efficiency in cooperation of members of cellulase enzyme system
76
M. Subhosh Chandra et al.