Substrate and metabolite diffusion within model medium for soft cheese in relation to growth of Penicillium camembertii.

Penicillium camembertii was cultivated on a jellified peptone-lactate based medium to simulate the composition of Camembert cheese. Diffusional limitations due to substrate consumption were not involved in the linear growth recorded during culture, while nitrogen (peptone) limitation accounted for growth cessation. Examination of gradients confirmed that medium neutralization was the consequence of lactate consumption and ammonium production.

Carbon and nitrogen substrates consumption, ammonia release and proton transfer in relation with growth of Geotrichum candidum and Penicillium camemberti on a solid medium.

It is difficult to determine fungal biomass growing on a solid medium directly. Therefore, indirect ways of measuring this growth have to be used instead. For this purpose, the kinetics of growth, of substrate consumption and of release of metabolites must be correlated.