Improved nonporous magnetic supports for immobilized enzymes

Abstract

Ni powders coated by deposition of TiO2 or controlled oxidation to NiO develop substantial resistance to corrosion. Chymotrypsin immobilized to these coated Ni supports shows very high stability of activity on storage. Chymotrypsin immobilized by adsorption and glutaraldehyde crosslinking was fairly rapidly eluted under operational conditions in the presence of substrate. If 3-aminopropyltriethoxysilane (APS) was used to produce a covalent linkage, desorption of enzyme still occurred because of relatively unstable bonding of the silane to the oxide surface. A more stable attachment was produced by joining together many silane links with a layer of polyglutaraldehyde. The mechanism of action of APS as a coupling agent under these conditions is discussed. gamma-Fe2O3, and particularly a Mn-Zn ferrite, are suitable magnetic support materials available with smaller particle sizes. Particles below 1 mum give the expected higher specific activities of immobilized enzymes.

Preparation and characterization of micron‐sized non‐porous magnetic polymer microspheres with immobilized metal affinity ligands by modified suspension polymerization

“…In contrast, non-porous support particles are less prone to fouling and are easier to clean than their porous counterparts and, therefore, are potentially more useful in purification of substances in dirty fouling feedstreams. 3,4 However, in order to obtain a comparable surface area of a typical macro-porous support, the dimensions for a non-porous particle have to be in the order of micron-size. 5 In addition, for the sake of easy separation, the magnetic particles should possess a strong magnetic responsiveness and high stability.…”

Immobilization of Protein on Silanized Orthopedic Biomaterials

“…Because of the unpredictable nature of the surface at the higher APS concentrations, concentrations above 2% were not pursued further. It has previously been estimated that 1-3 APS molecules per nm 2 constitute a monolayer 6 . Based on this estimate, an APS monolayer is formed on Co-Cr-Mo at a coating concentration of about 0.125%.…”

On the application of ‘seeding’ techniques in the primary separation of plasmid DNA from neutralised E. coli lysates

“…39 The results of flocseeding experiments conducted at 300 mL scale using magnetite and NiO-coated nickel particles at a final concentration of 3.33 mg mL −1 are summarized in Table 1. Although incorporation of either NiO-coated nickel powder or fine particle magnetite during the cell lysis step (i.e., by addition of particles in solutions 1 or 2) did not induce any visible reinforcement of the floc formed, phase separation was enhanced in all cases and separation of the flocculated solids from the plasmid liquor was significantly facilitated.…”