Abstract

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Staphylococcus sciuri strain XB1, a diesel degrading bacterium, was isolated from Igando dumpsite by continuous enrichment technique on diesel mineral salt medium (MSM). The isolate was identified using cultural, morphological, biochemical characteristics and complemented with analytical profile index. The isolate is yellowish, Gram-positive cocci, catalase positive, oxidase and coagulase negative. The isolate fermented glucose, fructose, maltose, trehalose and xylose. The antibiotic susceptibility pattern revealed that XB1 was susceptible to ofloxacin, perfloxacin, ciprofloxacin, sparfloxacin, but resistant to streptomycin, gentamycin, augmentin, amoxacillin. The XB1 also tolerated 3% salinity and exhibit specificity for another hydrocarbon substrate aside diesel. The degradation kinetics showed that XB1 had a biphasic growth with generation times of 11.925 d-1 and 17.825 d-1 between day 0-12 and 12-30 respectively. Gas chromatographic analysis revealed 55% of diesel was degraded at day 15 and 85% at day 30 respectively with near disappearance of the major hydrocarbon peaks. The percentage hydrocarbon fractions degraded at day 15 and day 30 respectively were 75.79% and 100% for nonane, 34.8% and 77.99% for tetracosane, and 59.96% and 81.86% for hexacosane. Therefore, based on the isolate competent on diesel the findings posited that XB1 is a candidate for further study and optimization for clean-up of polluted sites.

Keywords: Biodegradation, diesel, gas chromatography, continous-enrichment, Staphylococcus scuiri