title: Immobilization of cells with nitrilase activity from a thermophilic bacterial strain.
abstract: Cells of the moderately thermophilic Bacillus sp. UG-5B strain, producing nitrilase (EC3.5.5.1), which converts nitriles directly to the corresponding acid and ammonia, were immobilized using different types of matrices and techniques. A variety of sol-gel silica hybrids were tested for entrapment and adsorption of bacterial cells as well as chemical binding on polysulphone membranes. Activation of the matrix surface with formaldehyde led to an increase in immobilization efficiency and operational stability of the biocatalysts. Among the supports screened, membranes gave the best results for enzyme activity and especially operational stability, with retention of 100% activity after eight reaction cycles.
authors.affiliation: Department of Extremophilic Bacteria, Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria. lkabaivanova@yahoo.com
authors.forename: L
authors.initials: L
authors.lastname: Kabaivanova
authors.forename: E
authors.initials: E
authors.lastname: Dobreva
authors.forename: P
authors.initials: P
authors.lastname: Dimitrov
authors.forename: E
authors.initials: E
authors.lastname: Emanuilova
mesh_terms: D000619:Aminohydrolases / Q000378:metabolism*; D001407:Bacillus / Q000145:classification / Q000201:enzymology* / Q000254:growth & development; D019149:Bioreactors; D018914:Cells, Immobilized; D004785:Environmental Pollutants / Q000378:metabolism*; D006358:Hot Temperature; D007218:Industrial Microbiology / Q000379:methods*
chemical_list: D004785:Environmental Pollutants; D000619:Aminohydrolases; C021867:nitrilase