Biomedical applications of fibre-entrapped enzymes

Magnetic Nanoparticle-Containing Supports as Carriers of Immobilized Enzymes: Key Factors Influencing the Biocatalyst Performance

In this short review (Perspective), we identify key features of the performance of biocatalysts developed by the immobilization of enzymes on the supports containing magnetic nanoparticles (NPs), analyzing the scientific literature for the last five years. A clear advantage of magnetic supports is their easy separation due to the magnetic attraction between magnetic NPs and an external magnetic field, facilitating the biocatalyst reuse. This allows for savings of materials and energy in the biocatalytic process. Commonly, magnetic NPs are isolated from enzymes either by polymers, silica, or some other protective layer. However, in those cases when iron oxide NPs are in close proximity to the enzyme, the biocatalyst may display a fascinating behavior, allowing for synergy of the performance due to the enzyme-like properties shown in iron oxides. Another important parameter which is discussed in this review is the magnetic support porosity, especially in hierarchical porous supports. In the case of comparatively large pores, which can freely accommodate enzyme molecules without jeopardizing their conformation, the enzyme surface ordering may create an optimal crowding on the support, enhancing the biocatalytic performance. Other factors such as surface-modifying agents or special enzyme reactor designs can be also influential in the performance of magnetic NP based immobilized enzymes.

Phenylalanine ammonia-lyase entrapped in fibers

Phenylalanine ammonia-lyase extracted form Rhodotorula rubra (IFO 1101) was immobilized into cellulose triacetate fibers made hemocompatible by physical blend with a platelet anti-aggregating agent. The entrapped enzyme could operate at physiological values of phenylalanine and tyrosine reducing their level to traces within a few hours. The optimum pH value for the entrapped enzyme shifted from 8.0 to 9.0. At blood pH the activity was about 68 per cent of the maximum. The entrapped enzyme retained its original activity in blood for more than 50 days.