Development of bacterial cytochrome P-450(cam) (cytochrome m) production

Cytochrome P-450(cam) monooxygenase is an important bacterial redox enzyme system with potential commercial value for detoxifying trace hydrocarbon contaminants, catalyzing regiospecific hydroxylations, and amperometric biosensing. The present study was undertaken to increase productivity of this enzyme, which is induced in its host, pseudomonas putida PpG 786, by D(+)-camphor. Culture processes were studied in batch, fed-batch, and continuous modes to evaluate metabolic behavior and develop constitutive equations for specific rate of growth (micro), camphor utilization (q(p)). Fed-batch culture was characterized by an extended linear growth phase which is often encountered in hydrocarbon fermentations. Inhibition by the camphor solvent, dimethylformamide, was assessed. Production of the terminal protein of the p-450(cam) enzyme system, cytochrome m, was shown to depend on growth medium iron content in fed-batch culture and was increased by 130% over previously protocols by eliminating iron deficiency. A continuous process that enables greater production rates was developed by using oxygen enrichment while simultaneously reducing gas throughput. Camphor and oxygen requirements were determined for fedbatch and continuous growth.