Enzyme Gel Layer Reactors

If gel formation occurs, enzymes are effectively immobilized without meaningful changes in their microenvironment.31 Moreover, their settlement is partic- 

Enzyme gel layers can be built up under a number of fluid dynamic conditions. Unstirred and stirred batch reactors have been used as well as systems where the enzymatic solution is kept continuously flowing along semipermeable membranes until gel formation sets in. 

When unstirred batch membrane units are used as reacting vessels, a steady state mass balance on retained species, i.e., enzymes, leads to the evaluation of their concentration as a function of the distance from the membrane surface, x. Taking into account both convective and diffusive mass transfer mechanisms, the enzyme mass balance equation at steady state is as follows  

Proper boundary conditions can be derived assuming (a) complete enzyme rejection and (b) no enzyme loss, that is  

Maximum enzyme concentration occurs at the upstream membrane surface, (for x = 0) and it can be expressed as  

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The flexibility of enzyme gel layer reactors is fully exploited when multi-enzymatic reactions are to be performed. It may happen that enzymes involved in a given transformation cannot be subjected to the same immobilization procedure. Sequential enzyme gel layers can then be built up on the surface of a membrane in the proper sequence. Series reactions can be performed in such a set-up products from one enzymatic layer being fed to the following ones for further transformation.28 41... 

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