title: Effects of surface treatment and process parameters on immobilization of recombinant yeast cells by adsorption to fibrous matrices.
abstract: The effects of surface properties of Saccharomyces cerevisiae strains 468/pGAC9 and 468 on adhesion to polyethyleneimine (PEI) and/glutaraldehyde (GA) pre-treated cotton (CT), polyester (PE), polyester+cotton (PECT), nylon (NL), polyurethane foam (PUF), and cellulose re-enforced polyurethane (CPU) fibers were investigated. Process parameters (circulation velocity, pH, ionic strength, media composition and surfactants) were also examined. 80%, 90%, and 35% of the cells were adsorbed onto unmodified CT, PUF, and PE, respectively. PEI-GA pre-treated CT and alkali treated PE yielded 25% and 60% cell adhesion, respectively. Adsorption rate (K(a)) ranged from 0.06 to 0.17 for CT and 0.06-0.16 for PE at varied pH. Adhesion increased by 15% in the presence of ethanol, low pH and ionic strength, and decreased by 23% in the presence of yeast extract and glucose. Shear flow and 1% Triton X-100 detached 62% and 36% nonviable cells from PE and CT, respectively, suggesting that cell immobilization in fibrous-bed bioreactors can be controlled to optimize cell density for long-term stability.
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, Canada.
authors.forename: Peter
authors.initials: P
authors.lastname: Kilonzo
authors.forename: Argyrios
authors.initials: A
authors.lastname: Margaritis
authors.forename: Maurice
authors.initials: M
authors.lastname: Bergougnou
mesh_terms: D000327:Adsorption; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D018914:Cells, Immobilized / Q000378:metabolism; D002482:Cellulose / Q000737:chemistry; D003902:Detergents / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D005976:Glutaral / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D011094:Polyethyleneimine / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D003902:Detergents; D007477:Ions; D011140:Polyurethanes; D013501:Surface-Active Agents; D011094:Polyethyleneimine; D002482:Cellulose; D005947:Glucose; D005976:Glutaral