Diauxic production of glucose oxidase by Aspergillus niger in submerged culture: A dynamic model

On studying the production of glucose oxidase (GOD) by Aspergillus niger, we find that both growth and production are diauxic processes, with logistic and linear phases. The gluconic acid that is produced from glucose by means of enzyme action can therefore be considered as a useful source of carbon for growth, and does not interfere with the biosynthesis of GOD in spite of being a product of its activity. From a kinetic viewpoint, the enzyme is a primary metabolite, but this can only be proved by including the Luedeking and Piret equation in a dynamic model that takes into account the effects of hydrogen peroxide on GOD, as well as those of the catalase, which is also produced by the microorganism, on the hydrogen peroxide.