Journal of Bioremediation & Biodegradation

Abstrait

Bioremediation of Hexadecane and Diesel Oil is Enhanced by Photosynthetically Produced Marine Biosurfactants

Alberto Rosales Morales, Paniagua-Michel J

In the coastal environment of the Todos Santos Bay (Ensenada BC, Mexico), the sport fishing dock is chronically polluted due to frequent anthropogenic activity. The presences of aliphatic hydrocarbons in surface hydrocarbon-rich wastewater from this Bay reflect the differences in industrial and domestic pollutant activities. In this research, the bioprospection and screening of indigenous microbial mats led to the isolation of a strain of Phormidium sp. able to produce marine surface-active biosurfactants, which in turn contributed to bioremediate the levels of hexadecane and diesel. Field studies could corroborate the bioremediation potential of this strain. Our studies demonstrated that the marine cyanobacteria Phormidium sp. remove hexadecane (45%) and diesel oil (37%) from aqueous phase when grown in real seawater enriched with nutrients and in presence of these hydrocarbons within 10 days. The partially purified surface-active agents produced by Phormidium biodisk contributed to enhance the removal potential of this strain for hexadecane and diesel. In axenic cultures, the monospecific cyanobacterium Phormidium structured in biodisks mats exhibited degradative capacity on hydrocarbons in the range of C10–C28 carbon atom number in autotrophic conditions.

The photoautotrophic growth of the biodisks of Phormidium has been registered by the presence of photosynthetically produced pigments markers, which partially are genre specific features, viz, phycocyanine, phycoerythrin as well as zeaxanthin and other important carotenoids and chlorophylls. Moreover, photosynthetically produced oxygen is believed played an important role in biodegradation of hexadecane and diesel oil. The obtained results indicate, a high removal potential of Phormidium and an environmental safe alternative for mitigating oil pollution seashores, by the joint action of photosynthetically produced exopolysaccharides type biosurfactants.