Lr. Ludikhuyze et al., KINETICS FOR ISOBARIC-ISOTHERMAL INACTIVATION OF BACILLUS-SUBTILIS ALPHA-AMYLASE, Biotechnology progress, 13(5), 1997, pp. 532-538
Isobaric-isothermal inactivation of Bacillus subtilis alpha-amylase (B
SA, 15 mg/mL in Tris-HCl at pH 8.6) in the pressure range 1-750 MPa an
d the temperature range 25-85 degrees C could be accurately described
by a first-order kinetic model. The kinetic parameters (k, E-a, and V-
a) were calculated at different pressure and temperature levels. At re
ference temperature (40 degrees C) and reference pressure (500 MPa), i
sobaric-isothermal inactivation was characterized by an E-a value of 7
4.8 kJ/mol, a V-a value of -23.6 cm(3)/mol, and an inactivation rate c
onstant of 0.0343 min(-1). The influence of 15% glycerol on thermal an
d pressure-temperature stability of BSA was investigated. In both case
s, a stabilizing effect of this additive was found, since the k(ref) v
alue was significantly reduced. Furthermore, a pressure-temperature ki
netic diagram, indicating the possible synergistic and antagonistic ef
fects of pressure and temperature on the inactivation of BSA, was cons
tructed. Based on this diagram, a model describing the dependence of t
he inactivation rate constant on pressure and temperature, in the pres
sure range 250-750 MPa, was formulated.