Mathematical modelling and simulation of catechol production from benzoate using resting cells of Pseudomonas putida

Abstract

A catechol-accumulating mutant of Pseudomonas putida was isolated using NTG ( N-methyl- N′-nitro- N-nitrosoguanidine) mutagenesis. The mutant produced catechol in a medium containing benzoic acid. The use of optimal concentrations of carbon, nitrogen, phosphate and trace elements improved catechol productivity significantly. Spontaneous feeding of energy source and benzoate at a fixed interval prevented the degradation of catechol and thus increased catechol productivity. Among various operation modes, a two-stage biotransformation using resting cells was efficient for catechol production. The mathematical models comprising catabolite repression and enzyme induction were suggested for catechol production under resting cell conditions. The model fitted the experimental data well for various reaction conditions, such as initial substrate and cell concentrations. By mathematical simulation of the system, optimum acetate and benzoate concentrations were found. Acetate concentration was the most critical variable for the performance of catechol production. The model proposed was useful in describing biotransformation under resting cell conditions.