Sporulation of Penicillium camemberti in submerged batch culture

Sporulation of Penicillium camemberti was studied in submerged batch fermen tation. A defined medium was used with glucose and ammonium as C- and N-sou rces. Temperature was set to 25 degrees C at pH 5.6. Essential for submerge d sporulation was the presence of calcium (14 mM) which was adsorbed to the cell walls in all sporulating strains and inhibited mycelial growth. Aceta te led to highly branched conidiophores and was the second main factor for efficient sporulation. The chelating properties of citrate were necessary f or keeping calcium and phosphate in solution. Fermentation conditions allow ed high spore yields after 96 h (1.6 x 10(8) spores/ml). Cyclopiazonic acid , the mycotoxin common for P. camemberti was produced during fermentation. The levels observed (0.5-4 ppm at 96 h) were strain specific and not relate d to spore yield.