Reactor Design for Enzyme Catalysis

The easiest reactor to analyze is a steady-state CSTR. Biochemists call it a chemostat because the chemistry within a CSTR is maintained in a static condition. Biochemists use the dilution rate to characterize the flow through a CSTR. The dilution rate is the reciprocal of the mean residence time. 

Example 12.3 Suppose S P according to first-order, Michaelis-Menten kinetics. Find Sout for a CSTR. 

Solution Most enzyme reactors use such high concentrations of water that the fluid density is constant. Applying Michaelis-Menten kinetics to the component balance for a steady-state CSTR gives 

The reverse solution, finding the value of t needed to achieve a desired value for Saut, is easier. Equation (1.54) gives the reverse solution for the general case where the reaction rate depends on Sout alone and density is constant. Applying Equation (1.54) to the present case gives 

Most biochemical reactors operate with dilute reactants so that they are nearly isothermal. This means that the packed-bed model of Section 9.1 is equivalent to piston flow. The axial dispersion model of Section 9.3 can be applied, but the correction to piston flow is usually small and requires a numerical solution if Michaehs-Menten kinetics are assumed. 

When the product from a biochemical reactor is intended for use as a food or drug, the design process is subject to a set of government-mandated checks and balances to assure safe and effective finished products. The process must conform to a methodology known as current good manufacturing practice, or CGMP (usually shortened to GMP). Subject to this requirement for special care and documentation, the 

Confined Enzymes in Steady-State Flow Reactors 

SOLUTION Most enzyme reactors use such high concentrations of water that the fluid 

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