Diffusion Studies of Glucose and Sucrose in Chitosan Membranes and Beads for Enzymatic Production Processes

摘要

The diffusion of glucose and sucrose was investigated in membrane and bead experiments. Concentration-dependent diffusion coefficients of pure glucose and sucrose were determined in precipitated chitosan membranes of varying thickness using diffusion cell experiments. Contrary to fructose, the resulting diffusion coefficients of glucose and sucrose did not reach their free diffusion coefficients at infinite dilution suggesting additional interactions between chitosan and these two sugars. Counter-diffusion in bead experiments showed a good agreement between predicted and measured data allowing the inclusion of the diffusion data in the simulation of the proposed production process for laminaribiose. In conclusion, the encapsulation in chitosan presented a good trade-off between increased mass transfer resistance as evaluated by the Thiele modulus and improved thermal stability and antibacterial activity.