Impact of solid medium composition on the conidiation in Penicillium camemberti
Conidiation of an industrial strain of Penicillium (P.) camemberti, a ripening fungus, was examined on solid media. In order to evaluate the influence of nutritional factors on conidiation, we developed an inoculation and transfer procedure that allowed to obtain an homogenous mycelial biomass. Absence of conidiation was observed when ammonium sulphate and sodium nitrate were used as nitrogen sources. In contrast, conidiation increased significantly in the presence of ammonium phosphate or potassium nitrate with 4.8 × 106 and 12 × 106 spores ml−1, respectively. By using those optimal conditions, the influence of nutrient starvation or calcium supply on conidiation was studied. Under the conditions tested, nitrogen starvation and calcium supply were better inducers than carbon starvation. A high carbon-to-nitrogen (C/N) ratio provided the highest level of with 4.2 × 107 spores ml−1 and a sporulation index of 8.2 after 16 days of cultivation.
Journal: Process Biochemistry - Volume 41, Issue 6, June 2006, Pages 1318–1324