Image Analysis for Quantification of Fungal Biomass and Differentiation

Abstract

Fully-automatic image analysis methods are described for the measurement of vacuolation in filamentous fungi growing in dispersed form in submerged cultures. For Penicillium chrysogenum biomass from 0.03 to 38 gL -L , volumes of cytoplasmic and vacuolised or degenerated regions can be converted successfully into dry weight estimations, even when the medium contains suspended solids up to 30 gL -L . The vacuolation can be characterised in detail for physiological studies. For example, size and shape distributions of vacuoles can be measured, and are presented across the time course of a test fed-batch penicillin fermentation. Although off-line, the method is rapid enough (30 min per sample) to be considered for use as a process control tool. Links between cytoplasmic content and antibiotic production are being sought. The method might be used to provide data for structured models of fungal fermentations, and for control of product formation in those fermentations.