MATHEMATICAL-MODELING AND SIMULATION OF CATECHOL PRODUCTION FROM BENZOATE USING RESTING CELLS OF PSEUDOMONAS-PUTIDA

A catechol-accumulating mutant of Pseudomonas putida was isolated usin g NTG (N-methyl-N'-nitro-N-nitrosoguanidine) mutagenesis. The mutant p roduced catechol in a medium containing benzoic acid. The use of optim al concentrations of carbon, nitrogen, phosphate and trace elements im proved catechol productivity significantly. Spontaneous feeding of ene rgy source and benzoate at a fixed interval prevented the degradation of catechol and thus increased catechol productivity. Among various op eration modes, a two-stage biotransformation using resting cells was e fficient for catechol production. The mathematical models comprising c atabolite repression and enzyme induction were suggested for catechol production under resting cell conditions. The model fitted the experim ental data well for various reaction conditions, such as initial subst rate and cell concentrations. By mathematical simulation of the system , optimum acetate and benzoate concentrations were found. Acetate conc entration was the most critical variable for the performance of catech ol production. The model proposed was useful in describing biotransfor mation under resting cell conditions. (C) 1997 Elsevier Science Ltd.