ABSTRACT
Soil contamination with heavy metals is one of the most serious environmental problems, and more stringent regulations are necessary to confront this scourge. Although some metals perform specific biological functions, many others do not have a known role. Thereby, both prokaryotic and eukaryotic cells possess homeostatic mechanisms to regulate heavy metal concentrations, minimizing the potentials of toxic effects on living cells. The use of microbial surface-active compounds instead of those obtained by chemical synthesis to enhance the recovery of metals and other pollutants from soils is more acceptable due to their natural origin and singular properties that include low toxicity and high biodegradability. In fact, current challenges such as the design of strategies to minimize the production cost of these biomolecules at a large scale are being addressed successfully today. Application strategies of surface-active compounds varies depending on whether the producing microorganism is present in the cleanup process of soil or these biomolecules are added to the soil washing solution without the presence of the producing microorganism. In any case, microbial surface-active compounds tend to form complexes with heavy metals encouraging their effective desorption and removal from soils and sediments. Thereby, a significant reduction of these pollutants to acceptable levels can be achieved through a natural and eco-friendly process without environmental damages.
