Protease and urease production during utilization of diesel by fluorescent Pseudomonas species isolated from local soil

Bacteria, most prevalently the Pseudomonas species possess high capacity to utilize and degrade petroleum hydrocarbons and are classified as the hydrocarbonoclastic microorganisms. Many species of the genus Pseudomonas are notorious for their aerobic degradation capacity, extracellular enzyme production and are metabolically versatile organisms capable of utilizing a wide range of hydrocarbons and other compounds. In this study, the ability of diesel utilization by some locally isolated Pseudomonas species was tested. From a local red laterite soil, four different Pseudomonas species were isolated on King’s B medium, characterized, identified and tested their potential in utilizing diesel, a petroleum hydrocarbon. At the same time, production of protease and urease enzymes during the utilization of diesel was also assayed following the standard procedures. The isolates were grown well on diesel and subsequently produced the extracellular enzymes protease and urease at significant levels when compared to their production in the absence of diesel. Optimum temperature and pH for increased growth by four isolates was found to be 37oC and pH 8.0 indicating the maximum utilization of diesel. All the isolates showed maximum growth in medium with 100% diesel than 100% glycerol as carbon source, when tested with different proportions of diesel and glycerol as carbon sources. Plasmid profile of the isolates revealed that, all four Pseudomonas isolates harbored two low molecular weight plasmids; one with 3 Kb size and the other with 10 kb to 12 Kb size. The four Pseudomonas isolates of the present study were found to have potential in diesel degradation and can be recommended for bioremediation of sites that are contaminated with diesel.