Unlocking the potential of marine and extremophilic bacteria for the development of novel tailor-made amphiphilic compounds by the combination of biosynthetic genes.
Siderophores are capable to bond and transport Fe3+ ions featuring their activity for biological systems (plants and blood). To date, research related to the biotechnological production of biosurfactants has mostly focused on microbes isolated from soils, represented mainly by species of Bacillus, Pseudomonas, or yeasts. More recently and thanks to their specialised metabolism and physiology, marine and extremophilic bacteria have been identified as a prolific source for the discovery of novel compounds, e.g. amphiphilic molecules like Low Molecular Weight (LMW) biosurfactants. These are exemplified by the amphiphilic siderophores, also called marine siderophores, which have the ability to chelate and transport Fe3+ ions. Non-amphiphilic siderophores (generally non-marine) can be used to promote plant and microsphere growth by inhibiting the growth of plant-associated pathogens, bioremediation of heavy metals in contaminated soils, and in medical treatments (iron overload after a blood transfusion, bacterial infections and iron demanding tumour cells or antibiotics uptake facilitators). Amphiphilic siderophores were first identified in pathogenic terrestrial bacteria although subsequent research has shown extremely common production of amphiphilic siderophores in marine organisms. The molecular structures of siderophores, together with their physicochemical features will suggest potential for further applications or modification of known siderophores, either to enhance diagnostic or therapeutic potential. Siderophores-antibiotic conjugation formulas have been the major application that has been exploited to facilitate the uptake of antibiotics across the cell membrane, acting potentially as a “Trojan Horse”. The amphiphilic nature of biosurfactants and marine siderophores provides an exciting opportunity to develop methods of biosynthesis that would enable the exchange of their hydrophobic and hydrophilic parts. The development of such hybrid molecules would allow the exploration of new-to-nature compounds endowed with the combination of their respective properties, to address new chemical space and new applications.