Microemulsions as a novel tool for enhancing the bioremediation of xenobiotics

Abstract

Bioremediation is an advantageous and sustainable technology to remediate contaminated environments since it is cost-effective and environmentally safe. However, some pollutants such as most organochlorine pesticides and hydrocarbons are poorly soluble in water and thus tend to adhere tightly to soil particles. Therefore, the degradation of hydrophobic compounds is usually slow and frequently unsatisfactory due to the difficulties related to their transfer from soil particles to the aqueous phase, where these compounds are more available for degradative microorganisms. In this relation, a fundamental issue for the bioremediation processes is to overcome the limited accessibility of these hydrophobic pollutants for the microorganisms. As an alternative to synthetic surfactants, which are usually introduced into bioremediation processes with the aim of enhancing the bioavailability of hydrophobic pollutants, microemulsions have attained increasing significance both in basic research and environmental applications. Microemulsions consist of a combination of surfactants, co-surfactants, and oil phase and have demonstrated to be promising candidates due to its much higher solubilization capacity than surfactant micelles. This chapter compiles updated data related to general characteristics of microemulsions, with a special emphasis on the application of these systems as biotechnological tools for enhancing the solubilization and biodegradation of hydrophobic compounds, such as organochlorine pesticides, especially lindane.