Laboratory studies were carried out to assess the bacterial population dynamics
and distribution in composite soil samples collected from five (5) different automobile
workshops at various locations (Ikpa road, Nwaniba road, Udi street, Idakokpo lane and
Mechanic village) within Uyo metropolis. The hydrocarbon utilizing bacteria were isolated
and characterized from the soils of automobile workshops using cultural techniques. The total
heterotrophic bacterial count (THBC) ranged from 2.5 × 10
5 to 8.0 × 10
5 CFU/g of soil
sample, while the hydrocarbon utilizing bacterial count (HUBC) ranged from 2.5 × 10
4 to 4.4
× 10
4 CFU/g of soil sample. The bacterial isolates which were both Gram positive and Gram
negative belonged to the genera;
Bacillus
,
Flavobacterium
,
Achromobacter
,
Micrococcus
,
Citrobacter
and
Acinetobacter
. The total heterotrophic bacterial count (THBC) and
hydrocarbon utilizing bacterial count (HUBC) were higher in Ikpa road automobile workshop
and Nwaniba road automobile workshops respectively.
Bacillus species was found to be
present in all the soil samples analysed thus had the highest frequency 5(28%) of occurrence
while
Achromobacter species had the lowest frequency 1(6%) of occurrence. The presence of
these organisms in soils contaminated with spent and unspent lubricating oil and their
subsequent growth in enrichment medium supplemented with 1% spent lubricating oil suggest
their hydrocarbon utilizing potential, hence, their possible use for the bioremediation of soils
impacted with lubricating oil.
