Fig. 3

PP-V productivity of P. purpurogenum before and after replacing medium. a Pigment productivity after cultivation for 48 h and after replacing medium. b Pigment productivity after cultivation for 72 h and after replacing medium. Penicillium purpurogenum IAM15392 was grown in 500-mL Erlenmeyer flasks containing 100 mL of basal medium or 1 or 10 mM glutamine medium for 48 or 72 and transfer to fresh basal medium (no glutamine added). After then, mycelia were cultivated at 30 °C with shaking at 200 rpm for another 48 or 24 h (for a total of 96 h). The culture broth before and after replacing medium was centrifuged (1600×g, 4 °C, 15 min) before TLC analysis. The pigments in the supernatant were extracted with EtOAc, and were detected by TLC using a silica gel 60 plate with developing solvent mixture n-BuOH: AcOH: H₂O (12:3:5). “Culture condition” describes the medium in which P. purpurogenum IAM15392 was grown before (left) and after replacing the medium (right): Basal represents basal medium, 1 mM Gln represents basal medium containing a final concentration of 1 mM glutamine, and 10 mM Gln represents basal medium containing a final concentration of 10 mM glutamine. PP-V derived from 10 mM glutamine medium was used as a control. The arrow indicates when each medium was replaced