Supercritical CO2 extraction of an immunosuppressant produced by solid-state fermentation

Mycophenolic acid (MPA) is a secondary metabolite of Penicillium species with diverse biological properties and has clinical applications mainly as an immunosuppressive agent. Production of MPA was carried out using Penicillium brevicompactum (DSM 2215) by solid-state fermentation (SSF). Six different carbon sources (wheat bran, rice husk, rice bran, potato peel and rice husk - rice bran, rice bran-potato peel mixture) were examined by SSF in order to obtain the highest yield of mycophenolic acid. Rice bran-potato peel mixture was determined as the best solid substrate and used in scale up studies which was applied in the tray bioreactor. Supercritical CO2 and soxhlet extractions were analyzed for the recovery of MPA from the fermentation broth. The highest recovery (0.47 g MPA/100 g substrate) was obtained by supercritical CO2 at 30 MPa, 50 degrees C at a CO2 flow rate of 15 g/min with 10% ethanol as co-solvent for 3 h. The results obtained by the scale-up in bioreactor and optimization of supercritical CO2 entrained with ethanol can provide basis for the production of the immunosuppresant compound on industrial scale.