We present a model for the kinetics of microbial growth that incorporates the influence of the temperature variations that typically occur during solid-state culture in large-scale bioreactors. The model proposes that the specific growth rate constant depends on the level of an essential component within the biomass, with the rate of the synthesis and denaturation reactions of this component depending on temperature according to the Arrhenius equation. Model predictions were compared to literature data for the growth of Rhizopus oligosporus in three different situations: (1) incubation of cultures at different but constant temperatures; (2) initial incubation of cultures at 37 degreesC, followed by incubation at 50 degreesC; and (3) tray culture. The model agreed reasonably with all three sets of experimental results with the use a single set of parameter values. This approach to modeling has good potential for application in models of solid-state culture bioreactors. (C) 2004 Elsevier Ltd. All rights reserved.