Acid hydrolosis of bacterial cellulose reveals different modes of synergistic action between cellobiohydrolase I and endoglucanase I

Intact and partially acid hydrolyzed cellulose from Acetobacter xylinum wer e used as model substrates for cellulose hydrolysis by 1,4-beta-D-glucan-ce llobiohydrolase I-(CBH I) and 1,4-beta-D-endoglucanase I (EG I) from Tricho derma reesei. A high synergy between CBH I and EG I in simultaneous action was observed with intact bacterial cellulose (BC), but this synergistic eff ect was rapidly reduced by acid pretreatment of the cellulose. Moreover, a distinct synergistic effect was observed upon sequential endo-exo action on BC, but not on bacterial microcrystalline cellulose (BMCC). A mechanism fo r endo-exo:synergism on crystalline cellulose is proposed where the simulta neous action of the enzymes counteract the,decrease of activity caused by u ndesirable changes in the cellulose surface microstructure.