Copper adsorption and enzyme immobilization on organosilane-glutaraldehyde hybrids as support

Abstract

New hybrids SiglutX (X=1 to 3) were synthesized from silylant agents: (CH 3 O) 3 Si-R-NH 2 [R =-(CH 2 ) 2 -, -(CH 2 ) 2 NH(CH 2 ) 2 - and-(CH 2 ) 2 NH(CH 2 ) 2 NH(CH 2 ) 2 -]. The primary amine groups crosslinked with linear glutaraldehyde in two stages: crosslinking and sol-gel processes. The resulting polymers are amorphous, insoluble in organic as well as in acidic or alkaline aqueous media. The hybrids have a large capacity for copper adsorption with very similar kinetic behaviors, defining a plateau after 1 h. The adsorption increases with the increase of nitrogen atoms attached to the organic chain length of the precursor silylant, being 0.25±0.01, 0.37±0.01 and 0.50±0.01 mmol g -1 for X = 1 to 3, respectively. These hybrids also presented a good ability for immobilizing enzymes with distinguishable affinities. The amount of catalase and urease immobilization increased significantly from Siglutl to Siglut2, while the amount of glucose oxidase and invertase anchored decreased from Siglutl to Siglut2. Undefined amounts of enzyme immobilized for Siglut3 could be related to possible difficulties arising from its degradation during the interactive process.