Isolation and Characterization of Biosurfactant Producing Pseudomonas aeruginosa YLA03 and its Diesel Degradation Potentials

This work was aimed at isolating and characterising biosurfactant producing bacteria strain from diesel oil contamination sites. The potential of the strain  to degrade diesel oil n-alkanes was further studied. Soil samples were collected from diesel rich areas, and identified strains were grown on  minimal media that contained diesel oil as only carbon source. Enrichment culture technique was used to identify bacteria. Seventeen bacteria strains  were identified based on their capacity to use diesel oil as carbon source. Other qualitative screening methods were employed to determine the potential  to produce biosurfactants. Isolate A03 was the only candidate that shows positive signs for drop collapse, foaming, haemolytic, oil  displacement and emulsification tests. The effect of various culture parameters (incubation time, concentration of diesel, nitrogen source, pH and  temperature) on biodegradation of diesel was evaluated. Optimum pH was 8.0 at 35° C, while the incubation time at maximum bacteria growth was five  (5) days. The favourable diesel oil concentration was 7.5% for the isolate. The isolate has shown degradative ability towards dodecane, Tridecane,  tetradecane but was unable to degrade 2, 6, 10-trimethyl- dodecane. It degraded between 10.09% - 45.39% of individual diesel alkanes. The strain has  exhibited potential for degrading diesel alkanes and was identified as pseudomonas aeruginosa strain A3 (Accession Number: MZ027605) using the 16S  rRNA. Sequencing.