Mycelia and supernatant from the 3‐day‐old 20‐ml A. niger culture were separated by gravity filtration through a cotton ball. A mixture of 10 ml of chloroform and 5 ml of methanol was added to the supernatant, while mycelia were washed once with 10 ml of distilled water and soaked overnight in a mixture of 3 ml of chloroform and 1.5 ml of methanol, before 1.5 ml of MM without glucose was added to them. Subsequently, all mixtures were shaken vigorously, and centrifuged at 1500 g, room temperature for 3 min to separate the organic layer (bottom) from the aqueous layer (top). The organic layer was transferred to another glass vial, evaporated to dryness under a steam of nitrogen, and placed at –20°C for storage. The extracts were reconstituted in 200 µl of chloroform prior to analysis by liquid chromatography (LC)–MS.
For LC–MS and LC–MS/MS analyses, 40 µl of each sample was quantitated on an Ultimate DGP‐3600SD LC coupled to a Bruker MicrOTOF Q‐II MS instrument, both in the positive and negative ion modes, as described previously (Vinayavekhin et al.,2016 ).
For LC–MS and LC–MS/MS analyses, 40 µl of each sample was quantitated on an Ultimate DGP‐3600SD LC coupled to a Bruker MicrOTOF Q‐II MS instrument, both in the positive and negative ion modes, as described previously (Vinayavekhin et al.,