MICROBIAL DEGRADATION OF PETREOLEUM HYDROCARBONS BY BACTERIA
ISOLATED FROM DULIAJAN OIL SPILLS.
Microbial bioremediation functions basically on biodegradation, which may refer to complete
mineralization of contaminants like complex hydrocarbons to other simpler organic compounds
by biological agents like microorganisms. The bioremediation of hydrocarbons in contaminated
soils mixed cultures of hydrocarbon degrading bacteria was investigated. The mixtures or
consortia of bacteria denoted as KS1, KS2 and KJ14 were isolated from hydrocarbon
contaminated soil samples, as subjected to enrichment. The selection of potential crude oil
degrading microbial consortium was estimated by their ability to degrade the hydrocarbons
present in the soil. The experiment was carried out into basic steps: (i) isolation and purification
of indigenous bacteria from contaminated soil of duliajan refinery. (ii) Preparation of the soil,
which was used as medium. (iii) Determination of biological removal of oil from the soil. Results
indicated that in optimal environmental conditions, the bacterial isolates were able to degrade
upto 81.1% of oil during the period of 7 days. One of the major problems today is hydrocarbon
contamination resulting from the activities related to the petrochemical industry. Accidental
releases of petroleum products are of particular concern in the environment. Hydrocarbons
components have been known to belong t the family of carcinogens and neurotoxic organic
pollutants. Currently accepted disposal methods of incineration or burial insecure landfills can
become prohibitively expensive when amounts of contaminants are large. Mechanical and
chemical methods generally used to remove hydrocarbons from contaminated sites have
limited effectiveness and can be expensive. Microbial bioremediation is the promising
technology for the treatment of these contaminated sites since it’s cost effective and will lead
to complete mineralization. It was observed that the strain KJ14 showed comparatively high
efficiency of microbial degradation of the hydrocarbons to the other strains and led to
complete mineralization of the soil and could be used in agricultural activities.