Mass transfer and mathematical modelling of enzymatically catalyzed conversion in a dialysis membrane reactor

A dialysis membrane reactor can be used for enzymatically catalyzed conversions of low-molecular substrates /1/. The principle of the reactor is based on the physical separation of substrate and enzyme by a semi-permeable membrane. Substrate as well as product can pass through this barrier by diffusion while the enzyme is retained by the membrane. With the tanks in series model it is possible to describe enzymatically catalyzed processes in the dialysis membrane reactor. For the hydrolysis of lactose by ß-galctosidase from Kluyv. lactis and fragilis the calculations with the tanks in series model show good agreement with experiments. With an excess amount of ß-galactosidase, i.e. at least approx. 100 IU enzyme per milliliter enzyme solution volume the reactor was operated in a diffusion-limited way. The limiting factor with respect ot the conversion achievable is the diffusion rate of the lactose through the membrane.