Filtered medium (0.22 µm; Sterivex, Millipore) was pumped through an activated 1 g Bond Elut ENV SPE column at a flow rate of 10 mL min -1 . A medium blank was prepared with the culture medium without inoculation, incubated alongside the culture, and processed in the same way. SPE columns were rinsed with 6 mL of qH2O to remove salts, and CuLs eluted with 12 mL of MeOH. The MeOH eluents were concentrated to approximately 1 mL using a SpeedVac concentrator (Thermo Scientific) at 35 °C for 3 hours. MeOH extracts from five, 1 L cultures were combined and stored in 100% MeOH at -20 °C until analysis.