*4.5. Fermentation and Extraction*

For small-scale analysis, the strains with expression plasmids and the control strains were grown on CD plates with appropriate supplements for 3 days at 37 ◦C. Shortly after sporing, they were inoculated into 150 mL of CD-ST medium with appropriate supplements and cultured at 28 ◦C, 180 rpm. Meanwhile, they were spread on solid CD-ST medium with appropriate supplements, respectively. Four days later, the cultures were extracted with ethyl acetate and the organic phase was evaporated and dissolved in MeOH, which was analyzed by HPLC.

For compound isolation, the selected strain was initially handled the same as above. Then, a large-scale fermentation was performed in 500 mL Erlenmeyer flasks (total 5 L) for further incubation. The broth was extracted three times with ethyl acetate to provide a total of 15 L of extract solution. The organic phase was evaporated under reduced pressure to afford a crude residue (6 g).
