Characteristics of cellulase modified with a copolymer of polyethylene glycol derivative and maleic acid anhydride

Characteristics of modified cellulase with synthetic copolymers of polyethylene glycol alkylallylether and maleic acid anhydride were studied. Amino groups of the cellulase molecule were covalently coupled with the maleic acid anhydride functional group of the copolymer. The modification degree of the amino groups was controlled through the reaction process by changing the reaction time or the weight ratio of a synthetic copolymer to cellulase. As the modification degree increased, the activity of modified cellulase slightly decreased. At the maximum modification degree of 55%, the modified cellulase activity retained more than 90% of the unmodified native cellulase activity. The modified cellulase displayed a high stability of activity against temperature and pH. Finally it showed 30% greater conversion of filter paper as substrate at 90 h than in the case where native cellulase was used.