Rules for Choice of Reaction Parameters and Reactors

In this section only some rules of thumb are provided. 

Choice of reaction temperature activation versus deactivation 

Choice of reactor in the case of high degrees of conversion 

As very high degrees of conversion are achieved in a PFR with much smaller reactor volumes than in a CSTR (Lilly, 1976 Vieth, 1976) a PFR with immobilized enzymes is most suitable if complete conversion has to be achieved, as in the case of isomerization of glucose or the decarboxylation of D,L-aspartate with L-aspar-tate-/l-decarboxylase. 

Independently of enzyme stability an enzyme reaction at constant temperature and pH should be run with the smallest possible contribution by inhibition. For this reason, a CSTR is most suitable in the case of substrate inhibition because the substrate concentration is evened out across the reactor volume and thus minimized. In the case of product inhibition, however, a batch reactor or a PFR is preferred, as the reactor volume required for complete or nearly complete conversion is much smaller than in the case of a CSTR. 

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