Studies on reclamation of crude oil polluted soil by biosurfactant producing Pseudomonas aeruginosa (DKB1)

One of the primary issues noted worldwide in the marine environment is contamination by crude oil and it's by products. Contrasted with conventional methods, bioremediation offer a possible alternative to remove hydrocarbon pollution from the environment. The present study was undertaken to examine the capability of biosurfactant producing Pseudomonas aeruginosa (DKB1) on recovery of hydrocarbon contaminated soil. Initially Bacterial cell surface hydrophobicity (BATH) of the selected organism towards various hydrocarbons was observed in the following order; hexadecane (91.44%), sunflower oil (83.21%), olive oil (81.86%), hexane (74.78%), toluene (73.99%), diesel (72.60%) and a lower affinity was found against crude oil (46.98%). Further the biosurfactant produced by the candidate strain was extracted and the toxicity effect of the produced biosurfactant was tested against the micro crustacean, brine shrimp Artemia salina nauplii (Cytotoxicity) and the plants like cauliflower, cabbage, rice and green gram (Phytotoxicity). The result revealed that there was no toxicity observed in the tested A. salina and also in the tested plants. The biodegradation efficacy of the potent strain was screened by DCPIP (2, 6- Dichlorophenol indophenol) method using various hydrocarbons (kerosene, benzene, toluene and diesel). The result revealed that the selected organism has high hydrocarbon degrading potential and it turns the medium to become colorless. The crude oil biodegradation by the selected strain was evaluated by gravimetric analysis and also optimized the crude oil degradation potential. Finally the bioremediation of the crude oil contaminated soil was performed in situ laboratory scale experiment using the potent strain and the result indicated that there was up to 63.38% degradation of crude oil after 60 days of incubation. FTIR analysis result of the treated and untreated crude oil was confirmed that the candidate strain has the ability to recover the hydrocarbon polluted environment.