**1. Introduction**

Oil‐based fuels are currently the major source of energy for industry and daily life. However, leaching and spills that occur during exploration, production, refining, transport and storage cause pollution problems. Polycyclic aromatic hydrocarbons (PAHs) are organic molecules

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

that have two or more fused aromatic rings arranged in a linear, angular or cluster array. PAHs are found ubiquitously in the environment and are present in oil‐based fuels. Currently, PAHs had become increasingly important because they are considered as emerging contaminants by their high risk to humans and the environment. According to the US Environmental Protection Agency (EPA), they are toxic, mutagenic and carcinogenic, and are priority to be eliminated from the environment. There are several biological alternatives to eliminate PAHs and this chapter focuses on developments in bioaugmentation, biostimulation and bioatten‐ uation for the removal of PAHs.
