Multitubular reactors with immobilized L-phenylalanine ammonia-lyase for use in extracorporeal shunts

Hollow fiber cartridges of improved design have been loaded with L-phenylalanine ammonia-lyase [EC 4.3.1.5.] from Rhodotorula glutinis in order to prepare multitubular enzyme reactors for removal of L-phenylalanine from blood. The kinetics of the enzyme in free solution was investigated and the results showed a behavior similar to that reported for L-phenylalanine ammonia-lyase from other sources. On the other hand kinetic data with the reactors were obtained in a recirculating system by measuring the increase in trans-cinnamate concentration in the perfusate. The effect of changing the enzyme load in the hollow fiber cartridge, the length of the cartridge, the substrate concentration, pH as well as the flow rate and the temperature have been investigated. The results showed that the overall kinetics of the enzymic reaction in the multitubular reactor is not the same as that in free solution and the difference can be attributed to diffusion resistances in the hollow fiber system.