Marine bacteria for cleaning oil pollution

Marine bacteria for cleaning oil pollution

16. desember 2015
Seniorforsker

Biosurfactants produced by Norwegian cold-tolerated bacteria enhance biodegradation of oil pollution. They can be used as a “greener” alternative to chemical surfactant.

Biosurfactant

Biosurfactant is surface active compounds which are produced by microbes. Biosurfactants are structurally composed of hydrophilic (water loving) and hydrophobic (water repelling) regions therefore they can reduce surface tension and interfacial tension between two liquids help them mix together.

Biosurfactants are biodegradable and in general have low toxicity compared to chemical surfactants.

Microbes produce biosurfactant
Microbes which can live on oil such as cooking oil and fuel oil can produce biosurfactant in order to facilitate up-take of the oil into their cells.

Norut Narvik has carried out a selection of biosurfactant-producing bacteria from marine environment for use in oil pollution control. Sand and seawater samples from historical oil-contaminated sites such as Langesund, Hvaler, Tjøme and Bøstad in Lofoten, as well as from Oslo harbor were used for isolation of biosurfactant-producing bacterias.

Microbes which can produce biosurfactant when grown on kerosene and diesel were selected for lab scale production of biosurfactants.    

Effect at low temperature
At 13 degree, addition of the novel biosurfactants enhanced solubility of n-hexadecane in water, therefore increased biodegradation rate of n-hexadecane from 11.7 mg per day to 30 mg per day.

Lab scale testing of the novel biosurfactants as oil-washing detergent showed a comparable result as chemical surfactant SDS and Tween 80 at the same concentrations.

Usable alternative                    

Biosurfactants enhance solubility of oil, hence increase oil degradation rate.

The new biosurfactants produced by Norwegian cold-tolerant bacteria can be used as an environmentally friendly alternative to chemical surfactants.

However, increasing production yields of the biosurfactants is necessary to improve the cost competitiveness of biosurfactants to chemical synthesized surfactants.