Fabrication of enzyme-containing cellulose fibre materials from graft copolymers containing sulfo groups

Abstract

An analysis of the experimental data and their comparison with previously published [3] results led to the following conclusions: the rate of interpolymer reactions (IPR) involving lysozyme (LYS) and cellulose graft copolymer containing strongly acid groups (sulfo groups) is much lower than the rate of the reaction betweenChemical addition of enzymes to polymers containing ionizable groups makes it possible to create biologically active materials [1, 2]. The systematic study of the characteristics of the interpolymer reaction (IPR) involving water-insoluble graft copolymers of cellulose containing different ionizable groups (carboxyl, carboxylate, quaternary ammonium), and polyampholytes of enzymes allow determining methods for directed regulation of the composition and properties of the materials obtained [1][2][3]. In our previous studies [2, 3], we showed that the composition and properties of polyelectrolyte complexes (PEC) formed with a polyanion and enzyme grafted to cellulose are a function of the degree of association of the enzyme macromolecule in solution, the structure of the graft chains, and the conditions of conducting the IPR.We investigated the characteristics of immobilization of two enzymes differing by the degree of association of the macromolecules in solution [3]: the proteolytic enzyme trypsin (TR) and the bacteriolytic enzyme lysozyme (LYS), on modified cellulose fibre materials containing sulfo groups of different structure --graft copolymer of cellulose and polystyrenesulfonic acid sodium salt (C-gr-PSSA) and cellulose modified by graft polymerization of styrenesulfonic acid sodium salt and N,N'-methylene bisacrylamide [C-gr-(co-SSA--MBAA)]. Both cellulose graft copolymers were prepared by the radiochemical method in [4]. The ion-exchange capacity of these materials was 0.25 mmole/g.In immobilization of TR and LYS on modified cellulose fibre materials (CFM), the concentration C of protein in the solution and duration r of the process were varied. Enzyme-containing CFM were prepared in two versions. The first (periodic) version consisted of treating modified CFM with a solution of the enzyme in 0.05 M phosphate buffer with pH of 8.0 at 4~ bath modulus of 10, for different times, washing with the buffer, and drying at 20~ In the other version (continuous), the modified CFM was impregnated with a solution of the enzyme for 3 sec, squeezed out (85 % degree of wringing), kept damp for different times at 4~ washed with buffer, and dried at 20~ Preliminary experiments showed that TR and LYS are totally removed in washing the unmodified CFM treated with solutions of enzymes in the above conditions with buffer. To characterize the enzyme-containing CFM obtained, the following were determined: the amount of chemically bound protein by the method in [5] (by the difference between the amount of protein added to the reaction and the amount detected in the washing waters); proteolytic activity with respect to a highmolecular-weight substrate --casein by the method in [6]; bacteriolytic activity with r...

Properties of composites containing biologically active substances and the polymeric materials prepared from them

“…for their modification. Our data [4][5][6][7][8] showed that when graft copolymers of cellulose containing ionogenic groups are used for immobilization of enzymes, the required properties are basically obtained by altering the type, concentration, and localization of the ionogenic groups in the structure of the fibre. For unmodified fibre materials, this problem could be solved by using polymer matrices of varying structure, composites of different composition which include polysaccharides and their derivatives containing ionogenic groups in addition to biologically active substances, water-soluble synthetic polymers, and polyfunctional low-molecular-weight reagents [9][10][11][12][13].…”