P. aeruginosa, as well as many other Pseudomonas, can degrade aromatic hydrocarbons such as methylbenzenes, which are the by-products of petroleum industries and are commonly used as solvents for enamels and paints as well as in the production of drugs and chemicals. Methylbenzenes are considered as environmental contaminants that are present in the atmosphere, underground and soils, and in surface water (25). P. aeruginosa can break down toluene, the simplest form of methylbenzene. P. aeruginosa degrades toluene through the oxidation of the methyl group to aldehyde, alcohol, and an acid, which is then converted to catechol. Hence, P. aeruginosa can be used in pollution control (26).