title: Fast determination of operational stability of the soluble acetylacetone-cleaving enzyme Dke1 in an enzyme membrane reactor.
abstract: The main aim of this study was the determination of the operational stability of soluble Dke1 (EC 1.13.11.50) in an enzyme membrane reactor. In order to calculate the half-life of soluble Dke1, the K (M) of oxygen must be known. The determination of this constant was done using progress curve analysis (K (M) = 260 micromol l(-1)). In a next step, the reactor system was studied by building a mathematical model for calculation of the reactor system, using Berkeley Madonna ver. 8.0.1 software. After that, the determination of the half-life of Dke1 under operational conditions at different temperatures (5, 10, 15, 25, 30, 35 degrees C) was performed. The quantitative criterion for stability was the value of the first-order rate constant of monomolecular inactivation. The experiments showed that soluble Dke1 is poorly stable. The half-life ranged from 308 min at 5 degrees C to 9 min at 35 degrees C. This method for determining the half-life is quite applicable for enzymes which are poorly stable. In addition, both the storage stability and the operational stability can be determined.
authors.affiliation: Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Austria. hannes.hofer@gmx.at
authors.forename: Hannes
authors.initials: H
authors.lastname: Hofer
authors.forename: Walter
authors.initials: W
authors.lastname: Steiner
mesh_terms: D019149:Bioreactors; D049308:Dioxygenases / Q000378:metabolism*; D004795:Enzyme Stability; D006207:Half-Life; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism; D010422:Pentanones / Q000378:metabolism*; D012995:Solubility; D013379:Substrate Specificity; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors
chemical_list: D010422:Pentanones; C008790:acetylacetone; D049308:Dioxygenases; D010100:Oxygen