INCIDENCES OF GRAM NEGATIVE BACTERIA ISOLATED FROM MECHANIC WORKSHOP IRELE ONDO STATE

Mechanic workshops, particularly in developing countries like Nigeria, frequently operate without proper waste disposal practices. Used engine oil, petrol, diesel, grease, and other toxic substances are often dumped directly onto the soil, leading to persistent environmental degradation. This study investigated the presence and characteristics of Gram-negative bacteria in oil-polluted soil samples collected from a mechanic workshop in Irele Local Government Area of Ondo State, Nigeria. The bacterial isolates was characterized and identified mainly on the basis of their colonial morphology, cellular morphology, and biochemical reactions. 1g of soil was mixed with 9ml sterile distilled water. Serial dilutions were carried out up to 10-⁵. 0.1ml from 10-³ and 10-⁵ dilutions was plated on nutrient agar. Plates were incubated at 37 °C for 24 hours. Bacterial colonies were counted and selected based on morphology. Physicochemical parameters of the soil, including temperature (25°C), pH (5.74), and electrical conductivity (60 µS/cm), indicated an environment conducive to microbial activity. Results also revealed moderate colony growth, with biochemical tests identifying Moraxella species as the dominant isolate. The bacteria exhibited catalase and oxidase positivity, non-motility, and acid-only glucose fermentation, suggesting adaptive resilience to hydrocarbon-contaminated environments. It is recommended that Local authorities should create awareness campaigns about the environmental risks of unmanaged waste from auto-repair sites and introduce regulations for waste containment and soil recovery.