The Kinetics Of And Influencing Factors In Enzymatic Hydrolysis Of Cellulose

The rate of enzymatic hydrolysis of cellulose was very slow and restricted by many factors. With filter paper as substrate and the concentration of glucose measured by the colorimetry of DNS, the optimum condition for enzymatic hydrolysis of cellulose was studied.It was discovered that the activity of cellulase was sensitive to the variety of pH, the most suitable value of pH was 4.7-4.9. The most suitable temperature for enzymatic hydrolysis was the integration of the rate of enzymatic hydrolysis and the heat denaturalization of cellulase, as temperature rising, the former was accelerated, and however the latter was accelerated too. The most suitable temperature varied with other factors as time and pH, under the experimental condition, if the hydrolytic time was prolonged from 30 minutes to 60 minutes ,it changed from 57 ? to 55 ? in electrothermal water bath,from 56? to 52 ? in ultrasonic water bath. the rate of hydrolysis dropped. The initial rate was very quick, with hydrolysis proceeding the soluble product increased, which resulted in drop in the rate. Under different experimental condition, ultrasonic had different or even contrary influence on enzymatic hydrolysis. Water bath, in the field of the ultrasonic with proper frequency and intensity, was applied to facilitate the enzymatic hydrolysis of cellulose for quite a long time. Under the same experimental condition, the rate varied with the sorts of cellulose material and the means used to pretreat cellulose material. Certain concentration of non-ionic surfactant (tween) in the hydrolysis system stabilized cellulase and accelerated enzymatic hydrolysis. Iftween 80 or 40 was added into the hydrolytic system, the concentration of glucose was increased by some 12% in electrothermal water bath, by 14.6~40.5% in ultrasonic water bath.It was found that oxygen influenced hydrolysis rate too. Under the same experimental condition, the substrate was hydrolyzed by cellulase in both ultrasonic and electrothermal water bath, the concentration of reductive sugars measured in nitrogen-filled vessel was highest, the concentration in oxygen-filled was lowest, the concentration in air was between them. Compared with oxygen-filled vessel, after 6 hour the concentration of glucose in nitrogen-filled vessel was increased by some 23% in electrothermal water bath, by 47% in ultrasonic water bath.According to the mechanism of enzymatic hydrolysis of cellulose, the kinetic equation of enzymatic hydrolysis had been deduced with rational hypotheses; Parameters of the kinetic equation were figured out by nonlinear regression with the summation of the square of relative deviation minimized, the calculated value was coincided with experimental result comparatively. Rather applicable and feasible condition was put forward, which enhanced enzymatic hydrolysis effectively and made full use of cellulase for long; as a result, the production cost would be cut down greatly in practice.