Estimation of cell volume and biomass of penicillium chrysogenum using image analysis.

A methodology for the estimation of biomass for the penicillin fermentation using image analysis is presented. Two regions of hyphae are defined to describe the growth of mycelia during fermentation: (1) the cytoplasmic region, and (2) the degenerated region including large vacuoles. The volume occupied by each of these regions in a fixed volume of sample is estimated from area measurements using image analysis. Areas are converted to volumes by treating the hyphae as solid cylinders with the hyphal diameter as the cylinder diameter. The volumes of the cytoplasmic and degenerated regions are converted into dry weight estimations using hyphal density values available from the literature. The image analysis technique is able to estimate biomass even in the presence of nondissolved solids of a concentration of up to 30 gL(-1). It is shown to estimate successfully concentrations of mycelia from 0.03 to 38 gL(-1). Although the technique has been developed for the penicillin fermentation, it should be applicable to other (nonpellected) fungal fermentations.