Kinetic model of enzymatic hydrolysis of steam-exploded wheat straw

Abstract

► The kinetics of the cellulase hydrolysis of wheat straw is investigated. ► The exponential kinetic equation provides a good interpretation of cellulase action. ► Dependence of the reducing sugars on temperature and enzyme amount is found. ► Dependence of hydrolysis on time, enzyme concentration and temperature is obtained. The hydrolysis kinetics of steam-exploded wheat straw treated with cellulase NS 50013 enzyme complex in combination with β-glucosidase NS 50010 is studied. The time dependence of the reducing sugars amount is followed at varying the temperature value and the amount of the enzyme introduced. The activation energy determined on the ground of the rate temperature dependence stays unchanged in the course of the process. The preexponential factor decreases with the increase of the degree of hydrolysis and is responsible for the process rate decrease. A new expression for the dependence of degree of hydrolysis of one of carbohydrate polymers (cellulose) in wheat straw on the time, the enzyme concentration and the temperature is obtained. It is of practical importance as well because it provides estimation of the degree of hydrolysis required at predetermined values of the temperature, the enzyme concentration and the time used. The expression can be used for control of the enzyme hydrolysis of cellulose in the wheat straw.