[Characteristics of a new bioindicator and its testing in practice assays of thermal disinfection methods].
Thermolysin (EC 3.4.24.4) is a thermostable metalloproteinase isolated from Bacillus thermoproteolyticus. It has been tested for its suitability as a macromolecular bioindicator for the screening of thermal disinfection methods. Using the time- und temperature-dependent inactivation rate of the immobilized enzyme we get a measure if given parameters of disinfection have been maintained. In order to determine standard conditions of practical use, physico-chemical properties of the enzyme (pH- and temperature-optimum, Km, Vmax) were ascertained first. Then, thermal inactivation of thermolysin was analyzed for temperatures between 75 degrees and 93 degrees C and exposition time 3-20 min. This new method of testing thermal disinfection is compared with conventional physical and microbiological testing methods; in addition values of reference for selected disinfection programs were analyzed. The bioindicator proved to be stable for up to 12 weeks of storage (room temperature).
Senkpiel
K
K
Institut für Hygiene, Medizinischen Universität zu Lübeck.
Hoffmann
H
H
Kantelberg
U
U
Ohgke
H
H
Beckert
J
J
D004203:Disinfection / Q000379:methods*; D004355:Drug Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D012044:Regression Analysis; D013820:Thermolysin
D007202:Indicators and Reagents; D013820:Thermolysin
Charakterisierung eines neuen Bioindikators und seine Erprobung bei der Praxisprüfung thermischer Desinfektionsverfahren.