Abstract
A modeling of urea hydrolysis in chitosan medium and global enzymatic chitosan gelation kinetics was developed to better understand the gelation dynamics. The model was validated using experimental results in batch stirred reactor. Comparison between urea hydrolysis reaction rates in water and chitosan media shows that the chitosan has nearly no influence on the enzymatic kinetics parameters. Modeling results allowed decoupling gelation phenomena and urea hydrolysis reaction and pointing out the limitation of urea hydrolysis reaction by urea concentration depletion in chitosan medium. Monitoring pH and d(pH)/dt was useful for determining (i) the gelation time, (ii) the advanced gelation time, (iii) time of the maximum gelation rate and (iv) time of the maximum urea hydrolysis rate.