USE OF INT TO DETERMINE THE RESPIRATORY ACTIVITY OF IMMOBILIZED AND FREE PENICILLIUM-CHRYSOGENUM

The specific oxygen uptake rates (OUR) of kappa-carrageenan-immobilise d and free cell cultures of Penicillium chrysogenum were determined us ing an oxygen electrode in a closed chamber. This was compared with th e respiratory activity determined by the extent of staining with iodon itrophenyl tetrazolium chloride (INT). The degree of INT staining corr elated with the OUR; an increase in INT deposition corresponding to an increase in the measured OUR. The INT staining technique could theref ore be used to determine cell respiratory activity. In this way a prof ile of fungal cell activity throughout immobilised cell aggregates and free cell pellets was determined. In both types of cell culture, afte r the initial growth period only the peripheral biomass was observed t o be active.