Different bacterial and fungal strains, isolated
from petroleum hydrocarbon-contaminated soil, were tested,
in isolation as well as in combination, for their ability to
degrade total petroleum hydrocarbon (TPH) in soil samples
spiked with crude oil (2, 5 or 10 %, w/w) for 30 days. The
selected combination of bacterial and fungal isolates, i.e.,
Pseudomonas stutzeri
BP10 and
Aspergillus niger
PS9,
exhibited the highest efficiency of TPH degradation
(46.7 %) in soil spiked with 2 % crude oil under control
condition. Further, when this combination was applied
under natural condition in soil spiked with 2 % (w/w) crude
oil along with inorganic fertilizers (NPK) and different
bulking agents such as rice husk, sugarcane, vermicompost
or coconut coir, the percent degradation of TPH was found
to be maximum (82.3 %) due to the presence of inorganic
fertilizers and rice husk as bulking agent. Further, results
showed that the presence of NPK and bulking agents
induced the activity of degradative enzymes, such as catalase
(0.718 m mol H
2O
2 g
-1), laccase (0.77 µmol g
-1),
dehydrogenase (37.5 µg g
-1 h
-1), catechol 1, 2 dioxygenase
(276.11 µ mol g
-1) and catechol 2, 3 dioxygenase
(15.15 µ mol g
-1) as compared to control (without
bioaugmentation). It was inferred that the selected combination
microbes along with biostimulants could accentuate
the crude oil degradation as evident from the biostimulant-induced
enhanced activity of degradative enzymes.
