Impact of the spore production strategy of Penicillium camemberti in a solid medium on its germination abilities

The production process of Penicillium camemberti, a filamentous fungus of dairy interest, involves transition from a solid to a liquid medium, allowing acquisition of a sufficient quantity of spores for transfer to a bioreactor. This step is hardly referenced whereas its impact on growth can be substantial. The aim of this study was to define the best condition for spore production on solid medium that maximizes the quality of produced spores for the transition to liquid medium. A relationship between pre-culture time on a solid medium and future ability to germinate in a liquid medium was demonstrated. Spores tend to lose their ability to germinate with time. This behavior was less notable on a new solid medium. Washing the spores has not been shown to be beneficial for maximizing germination. Finally, a population effect was also observed with a total inhibition of germination at high spore concentration in liquid medium.