The uses of the various kinds of mineral oils in various industrial situations have made them an indispensable ingredient of the industrialization and development that has characterized the past century. Recent focus on health, safety and the preservation of the environment has turned the searchlight to the effects of mineral oils on the environment when they are accidentally spilled, or intentionally disposed of. Biodegradation, which provides an indication of the persistence of a particular substance in the environment, is the yardstick for assessing the eco friendliness of substances. Due to the poor biodegradation rates observable for mineral oils, various methods of bioremediation are currently being researched, with the isolation of various microbial species with the ability to use up mineral oils as a carbon and energy source. Ultimately, vegetable oil based hydraulic fluids will come to the fore as a suitable and more nvironmentally friendly solution to the demand for hydraulic fluids.