Indian Journal of Experimental Biology Vol. 57, November 2019, pp. 863-869 Fingerprinting hydrocarbons in a crude oil contaminated agricultural soil and its bioremediation employing bacterial consortium Sunita Varjani 1 * & Vivek N Upasani 2 1 Gujarat Pollution Control Board, Gandhinagar-382 010, Gujarat, India 2 Department of Microbiology, M G Science Institute, Ahmedabad-380 009, Gujarat, India Received 31 January 2019; revised 26 March 2019 Consistent fossil fuel exploration and production leads to environment deterioration. Oil spills make agricultural soil infertile and also pollute groundwater which becomes harmful to humans and other organisms. In this study, we explored ecofriendly method for biodegradation of petroleum hydrocarbons from crude oil contaminated agricultural soil using hydrocarbon utilizing bacterial consortium (HUBC). Soil microcosms were designed to study degradation efficiency of HUBC for petroleum hydrocarbons present in crude oil. Residual petroleum hydrocarbons were measured using gas chromatography. Bioaugmentation studies (with HUBC) showed 83.50±2.05% degradation of petroleum hydrocarbons contaminants at 60 days in crude oil contaminated agricultural soil microcosm. The hydrocarbon utilizing bacterial count in bioaugmented soil microcosm was noted to be 0.60±0.02×10 8 CFU/g at 60 days i.e. at the end of experiment, which was noted to be 4.90±0.07×10 7 CFU/g at the start of experiment. Ability of the consortium (used in the presented study) to survive in artificially contaminated agricultural soil microcosm and to degrade petroleum hydrocarbons effectively in soil microcosm conditions shows its potential to be used for bioremediation of agricultural soil and its restoration. Keywords: Ankleshwar oil field, Bioaugmentation, Cambay basin, Oil pollution, Soil microcosm Globally, different countries are competing for crude oil as it is a key energy resource 1 . Because of growing energy demands anthropogenic activities are increasing that causes the leap frog development in petroleum sector i.e. petroleum oil exploration and production 2,3 which leads to deterioration of environment 4,5 . When crude oil is explored, collected, stored and transported there are chances of its leakage or oil spillage which results in pollution of nearby agricultural land(s) and water resources 6 . Accidental and deliberate spillages causing natural environment contamination are prime threats to ecosystem as it transfers hazardous compounds present in crude oil into the food chain 2,7,8 . Though efforts are made to eliminate petroleum oil spills, persistent nature of crude oil compounds causes considerable environmental risk 1,6 . Agricultural soil fertility gets reduced which affects crop yields and harvesting. Contaminated soil has potential to pollute groundwater i.e. drinking water supplies, and hence it becomes harmful to humans and other organisms utilizing it 2,7,9 . Crude oil in its structure contains various components which are termed as petroleum hydrocarbons, they are mixture of hydrophobic structures viz. alkanes, aromatics, resins and asphaltenes 7,10 . US Environmental Protection Agency has classified the crude oil constituents as priority pollutants because of their detrimental impacts on human health and environment 11 . It has been reported that in case of terrestrial oil spill accidents, degradation of petroleum hydrocarbon pollutants occurs by native microorganisms and it is often a slow process 4,5 . Hence, challenge for researchers is there for finding technologically sound and effective method for remediation of contaminated soils 7,10 . Bioremediation has been reported as economically feasible and technologically sound clean-up method for treatment of petroleum oil polluted soil 12 . Currently, many research publications are available showing bioaugmentation for enhanced biodegradation of petroleum hydrocarbons in soil contaminated with petroleum hydrocarbons. However bioremediation is considered as site specific study 13 . Crude oil being complex mixture of various compounds to have complete and speedy degradation instead individual microbial species consortium of microorganisms is —————— *Correspondence: Phone: +91-9909828684 (Mob.) E-mail: drsvs18@gmail.com