Enzymatic technologies for remediation of hydrophobic organic pollutants in soil

Worldwide there are numerous contaminated sites as a result of the widespread production and use of chemicals in industrial and military activities as well as poor schemes of waste disposal and accidental spillages. The implementation of strategies for decontamination and restoration of polluted sites has become a priority, being bioremediation with biological agents a promising alternative. Enzyme-based technologies offer several advantages over the use of microbial cells, provided that the biocatalyst meets specific requirements: efficiency to remove the target pollutant/s, non-dependency on expensive coenzymes or cofactors, enzyme stability, and an affordable production system. In this mini-review, the direct application of enzymes for in situ soil bioremediation is explored, and also novel ex situ enzymatic technologies are presented. This new perspective provides a valuable insight into the different enzymatic alternatives for decontamination of soils. Examples of recent applications are reported, including pilot-scale treatments and patented technologies, and the principles of operation and the main requirements associated are described. Furthermore, the main challenges regarding the applicability of enzymatic technologies for remediation of hydrophobic organic pollutants from soil are discussed.