Hydrolysis of cotton cellulose by engineered cellulases from Trichoderma reesei

We have characterized the activities of TC, EG-rich, and CBH-rich cellulases from T. reesei and have shown that their activities towards cotton fabrics are influenced by ionic strength and adsorbed ionic species as well as by temperature and pH. Adsorption and kinetic experiments confirm that increasing mechanical agitation favors EG attack by greatly increasing the availability of sites for EG adsorption. It is not clear whether this is a consequence of fiber fibrillation damage or of improved access to fiber surfaces deep within the fabric structure. The enhanced rate of cellulolytic hydrolysis of mercerized cotton and the inhibitory effects on reactive and direct dyed fabrics are explained mainly in terms of increased or reduced availability of adsorption sites for CBHs and EGs. The implications for textile finishing are far-reaching. It is clear that a fabric's processing history (especially mercerizing and dyeing), construction, and level of applied mechanical agitation can be as important as the choice of enzyme composition and concentration in determining the consistency and quality of the end result.