Bioremediation of oil spillage in soils using
consortia of microbes beckons much exploration. The
present study involves bioremediation of oil-contaminated
soils from north Chennai, India, using indigenous microbial
consortia. Totally, 32 positive oil degrading isolates
were obtained from 3 different locations, i.e., petrol filling
stations, automobile workshops and oil refineries. Substrate
utilization patterns of individual isolates and the
consortial sets were observed. Mixture of three common
hydrocarbons (petrol, diesel and engine oil) was used for
studies. The substrate oil utilized by consortia was taken
for thin-layer and column chromatography which perfectly
resulted in varied fractions of oil compared to the
unused oil as control. The best consortia were used
directly for bioremediation experiment. Three different
oil-contaminated soils were used and bioremediation
patterns were observed. The rate of bioremediation differed
within soils, nevertheless all soils were almost
100 % reclaimed within 30 days. Bioremediation kinetics
showed that the process corresponds to first-order kinetics
and kinetic constants for the different soils ranged from
0.051 to 0.077/day. Assessment of detoxification of acute
phytotoxicity owing to the pollutant oil was done, and
results observed were significant. An increase of 25, 300
and 212 % in germination index, average growth index
and sustenance index, respectively, of
Trigonella foenumgraecum
Linn. in treated soils was observed, compared to
untreated soils. Thus, this study confirmed that microbes
in ‘Consortial Union’ serve as better treating agents in
bioremediation of oil-contaminated soils than individual
microorganisms.
