Fast determination of operational stability of the soluble acetylacetone-cleaving enzyme Dke1 in an enzyme membrane reactor.
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.
Hofer
Hannes
H
Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Austria. hannes.hofer@gmx.at
Steiner
Walter
W
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
D010422:Pentanones; C008790:acetylacetone; D049308:Dioxygenases; D010100:Oxygen