An important problem in Mexico is the immoderate pollution of waters, with pollutants like heavy metals, organic compounds and especially the oils and fats. In nature fats and oils decreeses the amount of disolved atmospheric oxygen and prevents the passage of light across the water, and they disable the photosynthetic process of the plants that live in this way and the oxygenation of the water is minor having impact on the species that they need from oxygen to survive.

As an alternative to reduce the concentration of fats and oils in waters, which acts as pollutants, which concentration must not exceed 100 milligrams per liter in sewers and strainers and 15 milligrams per liter in lakes, rivers, etc. In this work one proposes a treatment of waters using to the Pseudomonas aeuruginosa, which will act in waters contaminated with vegetable fats, using as tool of analysis the gas chromatography to follow the behavior of the bacterium on three fatty acids and the effect that they cause in the concentration of fats and oils in water. The Pseudomonas aeruginosa is capable of using the fatty acids as energy reducing the level of pollution that these produce. I manage to reduce up to 10 times the concentration of oils and fats in a water contaminated with 600 milligrams by liter having effect in fatty acids as the palmitic acid, stearic acid and oleic acid.