On the estimation of the pseudo-stoichiometric matrix for macroscopic mass balance modelling of biotechnological processes.

In this paper we propose a methodology to determine the structure of the pseudo-stoichiometric coefficient matrix kappa in a macroscopic mass balance based model. The first step consists in estimating the minimal number of reactions that must be taken into account to represent the main mass transfer within the bioreactor. This provides the dimension of kappa. Then we discuss the identifiability of the components of kappa and we propose a method to estimate their values. Finally we present a method to select among a set of possible macroscopic reaction networks those which are in agreement with the available measurements. These methods are illustrated with three examples: real data of the growth and biotransformation of the filamentous fungi Pycnoporus cinnabarinus, real data of an anaerobic digester involving a bacterial consortium degrading a mixture of organic substrates and a process of lipase production from olive oil by Candida rugosa.