Extraction of mycobactin and nocobactin-like siderophores.

After at least 2 weeks of inoculation, mycelia were separated from the culture supernatant by centrifugation. Twenty-five milliliters of LC-MS grade methanol was added to the cell pellet. After sonication and centrifugation, the organic phase was isolated and evaporated under reduced pressure. The resulting crude extracts were dissolved in methanol (MeOH). To obtain siderophores bound to gallium, a solution of gallium sulfate (20 mg in 30 ml MeOH) was prepared. Ten milliliters was added to crude extracts and evaporated under reduced pressure.