The Bioscientist
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Date
2015-01-01
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Publisher
The Faculty of Biosciences, Nnamdi Azikiwe University, Awka, Enugu State
Abstract
Soil samples collected from engine oil dump sites, diesel polluted sites and uncontaminated
plots (controls) were analyzed for oil-degrading and heterotrophic bacteria following standard
microbiological and biochemical methods. The pH readings of the different bacterial isolates
grown in Mineral Salt Media (MSM) for 16 days, Optical density readings, enumeration of
bacterial isolates in the different MSM were used as indices for comparison of the rate of
biodegradation of the diesel types.Nine indigenous microorganisms were isolated from both the
engine oil and petrodiesel contaminated soils using the enrichment technique. Oil degraders
isolated include: Pseudomonas aeruginosa, Pseudomonas cepacia, Staphylococcus schleiferi,
Pseudomonas fluorescens, Bacillus subtilis, Klebsiellapneumoniae, Staphylococcus
chromogenes, Escherichia coli and Micrococcus varians.Heterotrophic bacterial counts were
significantly higher (P < 0.05) in non-impacted than in impacted soils. Conversely, the
population of oil degraders was significantly lower in non-impacted than in impacted soils. The
pH range was 3.90-5.70 while the absorbance at 600nm range was 0.10 -1.17. The bacterial plate
counts in MSM supplemented with biodiesel were higher than in those supplemented with
biodiesel blend and petrodiesel. Results show that biodiesel is more easily and faster
biodegraded than petrodiesel. This finding could be exploited in case of oil-spill clean-up
campaigns.
Description
Keywords
Absorbance, Biodegradation, Biodiesel, Oil-spill, Petrodiesel