Siderophores in environmental research: roles and applications

Abstract

Siderophores are organic compounds with low molecular masses that are produced by microorganisms and plants growing under low iron conditions. The primary function of these compounds is to chelate the ferric iron [Fe(III)] from different terrestrial and aquatic habitats and thereby make it available for microbial and plant cells. Siderophores have received much attention in recent years because of their potential roles and applications in various areas of environmental research. Their significance in these applications is because siderophores have the ability to bind a variety of metals in addition to iron, and they have a wide range of chemical structures and specific properties. For instance, siderophores function as biocontrols, biosensors, and bioremediation and chelation agents, in addition to their important role in weathering soil minerals and enhancing plant growth. The aim of this literature review is to outline and discuss the important roles and functions of siderophores in different environmental habitats and emphasize the significant roles that these small organic molecules could play in applied environmental processes.

Figure 1

Representative examples of microbial siderophores and phytosiderophores with the stability constant of each type. Microbial siderophores consist of four main types. Hydroxamates produced by both bacteria (ferrioxamine B) and fungi (ferrichrome). Catecholate (enterobactin), carboxylate (rhizobactin) and mixed type (pyoverdine) produced by bacteria. The most common phytosiderophore is mugineic acid. All the chemical structures were drawn using ChemDraw Standard 13.0 software (PerkinElmer, Waltham, MA, USA).