The use of cellulose carbonate for the insolubilisation of enzymes

The use of cellulose xanthate for the immobilisation of biological molecules

The mercapto groups of cellulose xanthate can reversibly form disulphide bridges with L-cysteine. This property has been utilised for the immobilisation of a protein and an enzyme. These macromolecules, as polythiol derivatives, formed disulphide linkages with the matrix without serious disturbance of their active sites, became firmly bound to the xanthate, and were not eluted by normal washing conditions. Cellulose xanthate is a cheap, easily prepared matrix which permits a simple coupling reaction. The immobilisation process is selectively reversible.

Active insolubilized antibiotics based on cellulose-metal chelates

Cellulose was converted into a more reactive form by chelation with the transition metals titanium(III), iron(III), tin(IV), vanadium(III), and zirconium(IV). The remaining unsubstituted ligands of the transition metal ions were found to be amenable to replacement by electron-donating groups of antibiotic molecules. Ampicillin, gentamicin, kanamycin, neomycin, paromomycin, polymyxin B, and streptomycin were used as antibacterial antibiotics, and amphotericin B and natamycin were used as antifungal antibiotics. Antibacterial activity of the products was tested against two gram-positive and two gram-negative bacteria, and antifungal activity was tested against four fungi. That the antibacterial antibiotics had complexed with the cellulose-metal chelates was demonstrated in that the product cellulose-metal-antibiotic chelates exhibited antibiotic activities whereas the metal chelates of cellulose themselves were inactive. Of 140 tests conducted, cellulose-metal-antibiotic chelates were active in 102 cases. Since the antibiotic derivatives were water insoluble and in fact retain some of the antibacterial activities of the parent compounds, the chelation method provides a facile way of rendering cellulose surfaces, etc., resistant to microbial attack over and above that degree of protection afforded by noncovalent adsorption of the antibiotic to cellulose itself. The underlying principles of the chelation reactions involved are discussed in detail.