Isolation of Illudin M from Fermentation Broth

Illudin M was produced by submerged fermentation in stirred tank bioreactors [15 (link)]. The culture broth was separated from the biomass by centrifugation at 15,000×g for 30 min using the Sorvall RC-5B Refrigerated Superspeed Centrifuge (DuPont Instruments) at room temperature using the fixed-angle rotor Fiberlite™ F9-4 × 1000y (Thermo Fischer, USA). After centrifugation, a layer of antifoam formed on the surface of the supernatant which could not be fully removed. To eliminate antifoam residues, the supernatant was vacuum filtered using a Büchner funnel with a double layer of ø150 mm paper filter MN 615 (Macherey–Nagel) and an additional 4 cm layer of cotton wool on top. This setup was sufficient to clear > 10 L supernatant from antifoam without clogging and no significant drop in performance. The filtrate was collected in glass bottles and stored at 4 °C in darkness until further usage.