Investigation of the mechanism of iron acquisition by the marine bacterium Alteromonas luteoviolaceus : Characterization of siderophore production

Iron availability in the ocean ranges from one to four orders of magnitude below typical growth requirements of bacteria. The discrepancy between Fe availability and requirements raises questions about the mechanisms that marine bacteria use to sequester Fe3+. Surprisingly little is known about the siderophores produced by marine bacteria. Growth conditions of an open-ocean bacterial isolate, Alteromonas luteoviolaceus, were investigated to determine the conditions which enhance siderophore production. Methods to isolate and purify the siderophores were determined. The siderophores produced by A. luteoviolaceus were partially characterized by mass spectral analysis, amino acid analysis, qualitative analytical tests, chemical degradation, and nuclear magnetic resonance. A new set of outer membrane proteins was also produced when the bacterium was grown under Fe-limited conditions.