Estimating growth kinetics of Penicillium chrysogenum by nonlinear regression

Abstract

A simple unstructured microbial growth model was used to describe the dynamics of fungal growth in batch cultures. Biokinetic parameters were evaluated using the integral form of the Contois equation by nonlinear regression. Monte Carlo simulations and sensitivity analyses were performed to evaluate the effectiveness of the nonlinear parameter estimation technique for obtaining unique and accurate estimates of the Contois equation parameters. This technique was subsequently used to estimate growth kinetic parameters of Penicillium chrysogenum grown on glucose. Microbial growth and substrate depletion were accurately described by the Contois equation and the kinetic parameters were estimated as μ max=0.103 h −1, K c=0.145 and Y= 0.445. The applicability of the Contois equation to describe both pellet and filamentous fungal growth was verified using previously published data. The use of the integrated Contois equation is advantageous as biokinetic parameters can be estimated from a single substrate depletion curve.