Microbial enhanced oil recovery (MEOR) is a popular method which relies on microorganisms and their metabolic products to mobilize residual oil. For example, some bacteria are able to produce emulsifier, and others can produce biosurfactant. These two bio-products can work together to help form a stable water-oil mixture with good mobility, which makes it easier to remove oil. However, the bacteria producing emulsifier can feed on oil but those biosurfactant-producing kinds cannot. As a result, no matter by injecting nutrients or adding other kinds of surfactant along with water, surfactant cannot be blend with oil efficiently.

Our project is to solve this problem by constructing a bacterial strain that can utilize oil as its carbon resource as well as producing emulsifier and biosurfactant at the same time.

We start with a Pseudomonas stutter strain, a kind of bacterium that can produce a special kind of emulsifier and live well in the oil reservoirs all by itself. To make it more powerful, we plan to express the rhamnosyltransferase operon genes rhlABRI from Pseudomonas aeruginosa in it, so that it can produce rhamnolipid, a biosurfactant that can mobilize residual oil in the reservoir by reducing the oil-water interfacial tension (IFT).