title: [Combined effect of temperature a(W) and pH on proteases from Pseudomonas and Bacillus spp].
abstract: The factors affecting protease activity were investigated on certain media. Five strains of Bacillus (B.) cereus, four strains of B. subtilis, five strains of Pseudomonas (Ps.) aeruginosa and two strains of Ps. fluorescens produced the proteases that were tested. The enzyme activity was evaluated under 32 different combinations of temperature (2 and 7 degrees C), water activity (aw) (0.80-0.98) and pH (4.0-7.3). A decrease in water activity and pH and/or temperature caused a decrease in protease activity. It appeared that the combined effect of temperature, aw and pH influences enzyme production significantly compared with the influence of single environmental factors. Temperature plays the crucial role in these reactions. Enzyme activities could be observed even at low temperature. Although the exoprotease of Ps. spp. showed intense activity at refrigeration temperature, low pH and aw, Bacillus proteases were comparably less active under the same conditions, but nevertheless proved to be significant.
authors.affiliation: Institut für Lebensmittelhygiene, Veterinärmedizinischen Fakultät, Universität Leipzig.
authors.forename: C
authors.initials: C
authors.lastname: Klug
authors.forename: K
authors.initials: K
authors.lastname: Fehlhaber
authors.forename: U
authors.initials: U
authors.lastname: Müller
authors.forename: P
authors.initials: P
authors.lastname: Braun
mesh_terms: D001409:Bacillus cereus / Q000201:enzymology*; D001412:Bacillus subtilis / Q000201:enzymology*; D010450:Endopeptidases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D011551:Pseudomonas fluorescens / Q000201:enzymology*; D013045:Species Specificity; D013816:Thermodynamics
chemical_list: D010450:Endopeptidases
vernacular_title: Kombinierter Einfluss von Temperatur, aw- und pH-Wert auf die Aktivität der Proteasen von Pseudomonas- und Bacillus-Stämmen.