Immobilization of cell-associated enzyme by entrapping in gluten matrix

Gluten is advantageous for use as a new base material for cell and enzyme i mmobilization because it is biodegradable, cheaper than other natural polym ers and readily available. In this work, a procedure for immobilization of cell-associated enzymes by entrapping within gluten matrices was developed. According to this method, cells of E. coli containing penicillin G acylase were mixed with gluten solution during the formation of gel, and the resul tant gel was hardened by the addition of oxidized starch or glutaraldehyde. Scanning electron micrographs of the cell-immobilized preparations indicat ed that they were porous and the pore size decreased with increasing the do sage of cross-linking agent. Oxidized starch was superior to glutaraldehyde as the crosslinker, since the gel matrices hardened by the former were mor e accessible to the substrate and less harmful to the enzyme. The immobiliz ed preparations in the form of either a single sheet or small pieces contai ning a biomass concentration up to 10%, w/w were effective for catalyzing t he hydrolysis of penicillin G. Neither the optimal temperature nor optimal pH for the activity of cell-associated enzymes was changed by immobilizatio n. In order to establish a membrane reactor for large-scale production. a s tainless steel net could be used as the support for formulating a cell-immo bilized gluten sheet.