The "FERMEX" method for metabolite-enriched fungal extracts.

The FERMEX (Fermentation Extract) program was a highly successful source of microbial natural product molecules for pharmaceutical lead discovery. The program was based on the observation that solid fermentations of fungi generally exhibited more complex metabolite profiles than when the same strains were grown on liquid medium. To produce interference-free fermentations and improve organic product recovery, fungi colonized homogeneous media-saturated vermiculite thus promoting cellular and metabolic differentiation. Secondary metabolites in fungal cells were extracted from the substratum and medium with methyethylketone to generate metabolite-enriched screening samples. The necessary equipment, protocol, and media recipes are described along with examples of bioactive fungal metabolites produced in this system.