Effect of Ferric Iron on Siderophore Production and Pyrene Degradation by Pseudomonas fluorescens 29L

Abstract

The effect of ferric iron [Fe(III)] on pyrene degradation and siderophore production was studied in Pseudomonas fluorescens 29L. In the presence of 0.5 microM of Fe(III) and 50 mg of pyrene per liter of medium as a carbon source, 2.2 mg of pyrene was degraded per liter of medium per day and 25.3 microM of 2,3-DHBA (2,3-dihydroxybenzoic acid) equivalent of siderophores was produced per day. However, the pyrene degradation rate was 1.3 times higher and no siderophores were produced with the addition of 1 microM of Fe(III). Similar trends were seen with 50 mg of succinate per liter of medium as a carbon source, although the growth of strain 29L and the succinate degradation rate were higher. In the absence of siderophore production, pyrene and succinate continued to be biodegraded. This indicates that Fe(III) and not siderophore production affects the hydrocarbon degradation rate. Only 18% of strain 29L mutants capable of growth on pyrene produced siderophores, while among the mutants capable of growth on succinate, only 10% produced siderophores. This indicates that siderophores are not required for pyrene biodegradation. Fe(III) enhances pyrene degradation in Pseudomonas fluorescens 29L but it may be utilized by mechanisms other than siderophores.

In silico analysis of protein toxin and bacteriocins from Lactobacillus paracasei SD1 genome and available online databases

“…It can facilitate iron availability and cause anemia and edema in the host [76]. These microorganisms need iron as a cofactor for several enzymes [78]. Lactobacilli can grow normally without iron, which is an ecological advantage in the natural environment, where they compete with pathogenic bacteria.…”

Amphiphilic siderophore production by oil-associating microbes

“…11 The rate of hydrocarbon degradation has been demonstrated to increase in the presence of iron, however, the mechanisms of iron acquisition by these microbes have not been well 55 characterized. 12,13 Many marine bacteria produce siderophores in response to the extremely low concentration of soluble iron in surface ocean waters. Siderophores are low molecular weight, iron(III) chelators that bacteria secrete to solubilize and transport iron(III) into the cell.…”

Isolation, Structure Elucidation, and Iron-Binding Properties of Lystabactins, Siderophores Isolated from a Marine Pseudoalteromonas sp.

“…10,11 Siderophores may play a role in biodegradation by facilitating acquisition of iron, a limiting nutrient in the ocean, as well as in other environments. 12,13 While adding iron to a hydrocarbon-degrading bacterial culture can stimulate the biodegradation rate, 14,15 the mechanisms of iron acquisition by these microbes have not been well studied. Siderophore production by the oil-degrading Marinobacter hydrocarbonoclasticus was investigated, and it was found to produce petrobactin, a bis-catecholate, -hydroxy siderophore.…”