Used engine oil is a type of engine oil that has reached the end of its useful life in the automotive industry due to changes in chemical, physical, and microbiological composition. It contains higher levels of inorganic and inorganic elements, as well as hazardous microorganisms, making disposal difficult. That's where biodegradation comes in. Microbial degradation/biodegradation is a very useful process for the breakdown of used motor oil since it degrades hazardous chemicals as well as harmful microorganism when executed properly. Bacteria, fungi, algae, and yeast can all help in biodegradation. However, bacteria, rather than other microorganisms, play the most important role in biodegradation. Pseudomonas spp., Enterobacter sp., and Bacillus sp. are the bacteria with the greatest ability to breakdown used engine oil from soil. Used engine oil is only discarded in drains, open areas, or waste water all over the world. Which has an impact on the environment, as well as aquatic pollution and health issues. When used engine oil comes in interaction with soil, it causes microbiological and chemical properties to change. This has an impact on the development of many plants in the soil. Hazardous metals such as Zn, Pb, Cr, Fe and PAH (poly aromatic hydrocarbons) as well as bacteria such as Micrococcus, Rhodococcus, Bacillus sp., and Paenibacillus sp., are found in used engine oil polluted soil.

Keywords: Used engine oil, biodegradation, used engine oil contaminated soil, Pseudomonas spp., Enterobacter spp.