Psychrotolerant hydrocarbon-degrading Rhodococcus strains isolated from Antarctica

RUBERTO L., VAZQUEZ S., MAC CORMACK W

Bariloche, Rio Negro, Argentina

Congreso; XXXIX Reunión Anual de la SAIB; 2003

SAIB

When hydrocarbons are spilled on pristine soils, bioaugmentation represent the most promising option to reduce hydrocarbon contamination. In these cases, temperature is one of the most important factor affecting biodegradation activity and only psychrotolerant microorganisms are adequate for designing bioremediation processes in extremely cold areas as the Antarctic continent. Seeing as Rhodococcus strains seem to be one of the most efficient hydrocarbon-degrading bacterial group in Antarctica, we reported here the taxonomic and physiological characterization of three Antarctic Rhodococcus strains (ADH, DM1-21 and DM1-22) with hydrocarbon degradation activity. Isolation was made from polluted soils from Jubany and Marambio stations. Rhodococcus strains were characterized by biochemical and molecular test. ADH and DM1-22 were related to R. erythropolis whereas DM1-21 was related to R. erythreus. Strains showed high hydrocarbon-degrading capacity on aliphatics and complex mixtures but not on aromatic hydrocarbons. Specific growth rate in cultures with n-hexadecane ranged between 0.028 h-1 (ADH) and 0.038 h-1 (DM1-21) and 84-86 % of the hydrocarbon was removed in all cases. Bioremediation performed in microcosms systems in Antarctica showed that the presence of the isolated strains enhances the biodegradation activity of the natural microflora. These results showed that the isolated psychrotolerant Antarctic Rhodococcus are useful for application in hydrocarbon bioremediation processes in Antarctica and other cold areas.