Segregated enzyme reactors

In these reactors, enzymes or cells are not immobilized, but only confined to a well defined region of space. The segregation of biocatalyst in the reaction vessel is achieved by means of an ultrafiltration or microfiltration membrane 

The development of hollow fibers with diameters down to about 100 microns makes possible tube-and-shell reactors with a high surface-to-volume ratio. Biocatalytic reactors can segregate enzymes or cells either within the hollow fiber lumen,46 within the shell surrounding the outer surface of the fibers,44 45 57-59 or within the porous membrane support.42 45 47 53 

Segregated enzyme reactors avoid the negative aspects of immobilization techniques such as steric hindrance and enzyme deactivation due to coupling. 

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Segregated enzyme reactors are based on the method of confining the enzyme in a well-defined region of space. This technique can be applied to hollow fibre... 

Most of the membrane segregated enzyme systems previously examined suffer some constitutive drawbacks which limit their yield and area of application. When enzymes are entrapped within the sponge of asymmetric membranes, product and substrate mass transfer occur mainly by a diffusive mechanism reactor performance is then controlled only by means of the amount and kind of charged enzyme, and the fluid dynamics of the solution in the core of the fibers. UF or RO fluxes, moreover, result in enzyme losses. Enzyme crosslinking in the membrane pores can reduce these losses, but it can lead to an initial activity loss, as compared to that of the native enzyme. Of course, once the enzyme is deactivated, it makes the reactor useless for further operation. Such immobilization techniques are seldom useful for microbial cells due to their large size. 

Segregation of a catalyst (and cofactor) in a reactor Segregation of enzymes with respect to molecular weight on ultrafiltration membranes... 

Many of the equations employed in unstructured and non-segregated models derive from those of enzymatic kinetics (Sinclair and Kristiansen, 1987 Nielsen and Nikolajsen, 1988). Cells are considered as chemical reactors that support thousands of complex reactions catalyzed by enzymes that allow the conversion of substrates into secreted products. The equation formulated by Michaelis and Menten represents the enzymatic conversion rate of a unique substrate into one product (Equation 14). 

Reactors with Enzymes Segregated in the Lumen of Hollow Fibers... 

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