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Most bacteria characterized as hydrocarbon degrading are isolated from the terrestrial environment and have very limited or no application under estuarine/hyper-saline conditions. The collective efforts of these hydrocarbon-degrading bacteria help in the preservation of the environment under man-made disasters. However, the process has a long lag phase, since the contaminated ecosystem undergoes a process of natural selection of efficient hydrocarbon degrading bacteria. This paper uses a microbial consortium designed from a library of soil isolates, composed of four members; strain Pseudomonas NCC.DSS6, P. NCC.DSS8, P. NCC.GSS3 and P. putida, which can attack various fractions of crude oil. To extend the capacity of the consortium for degradation of hydrocarbons in marine environments or estuarine conditions the key is the requirement of an osmotolerance function. Hence, in the present study, to provide osmotolerance to these soil isolates, the E.coli pro U operon was subcloned into a broad-host range vector and transferred into the members of the microbial consortium. The non-specific basal expression of the pro U operon, under the control of tac-lac promoter was demonstrated by the ability of the transformed organisms to grow under hyper-saline conditions. The degradation capacity of the engineered consortium was also studied using a designed model petroleum mixture. The study underscores the potential of the osmoregulatory function for degradation of anthropogenic molecules in marine niches.

Oil spills generate enourmous public concern and highlight the need for cost effective and environmentally acceptable mitigation technologies. Physico-chemical methods are not completely effective after a spill. Hence, there is a need for improved and alternative technologies. Bioremediation is the most environmentally sound technology for clean up. This report intends to determine the potential of a bacterial consortium for degradation of Gulf and Bombay High crude oil. A number of bacteria were isolated from an acclimated semicontinuous reactor fed with crude oil. A four membered consortium was designed that could degrade 70% of the crude oil. A member of consortium produced a biosurfactant, rhamnolipid, that emulsified crude oil efficiently for effective degradation by the other members of consortium. The wide range of hydrocarbonoclastic capabilities of the selected members of bacterial consortium leads to the degradation of both aromatic and aliphatic fractions of crude oil in 72 hours.