(Bio)surfactant and Bioremediation, Successes and Failures

Application of bioremediation technologies for hydrocarbon contaminated soil is often limited by the presence of high recalcitrant and low bioavailable compounds within the mixture of contaminants. It has been demonstrated that slow release of these compounds from the soil particles into the water phase could represent a rate-limiting factor for bioremediation processes, leading to inability to reach the target of remediation. Due to their surface properties, both chemically synthesised surfactants and microbial produced surfactants (biosurfactants) are used in soil remediation processes to improve removal rate of pollutants in conventional methods. Surfactants are utilised within chemico-physical remediation technologies such as in situ soil flushing and ex situ soil washing for remediation of unsaturated zone and pump and treat technologies for aquifer remediation. However, due the complex interactions between the amphiphilic molecules, the cell surfaces and their abiotic environment, both cases of success and failures have been reported in literature. In this chapter the current knowledge about the natural role of biosurfactants and the effect of (bio)surfactants on the biological systems and abiotic compartments during bioremediation treatments are reviewed.