DEGRADACIÓN DE FENANTRENO POR MICROORGANISMOS HALOFÍLICOS AISLADOS DE SALINAS PAMPEANAS

DI MEGLIO, LEONARDO; BUSALMEN, JUAN PABLO; NERCESSIAN, DÉBORA

Congreso; X CONGRESO ARGENTINO DE MICROBIOLOGIA GENERAL SAMIGE; 2014

Samige

Polycyclic Aromatic Hydrocarbons (PHAs) are compounds with two or more fused aromatic rings that are highly toxic because of  their mutagenic and carcinogenic effects on living organisms. Bioremediation technology employs microorganisms which are able to metabolize toxic compounds and transform them into harmless ones. In this direction, much has been studied about bacterial remediation, but the knowledge about metabolic pathways and enzymes involved in hydrocarbon degradation in hypersaline environments is scarce. One important source of PHAs pollution is waste water of oil production process, which is indeed generated in large amount. Because of its high saline content, microorganisms conventionally employed in PHAs remediation cannot be effective in biological treatment of this waste water, which took researchers to consider extremophilic microorganisms, as halophilic archaea. We isolated and identified nine microorganisms (seven Archaea and two Bacteria) of La Colorada Grande, Salitral Negro and Guatraché saltern ponds located in La Pampa province. They were tested, along with other  halophilic microorganisms and consortia, to evaluate their hydrocarbon degrading capacity. For this, degradation assays were performed in liquid medium under low oxygen concentration in the presence of 0.02% phenanthrene, for four weeks.Degradation products and the remaining phenanthrene were extracted from the extracellular medium with ethyl acetate and analyzed by High Resolution Liquid Chromatography (HPLC). Chromatograms evidenced complete phenanthrene degradation by eight of the tested strains, to different byproducts, while an additional strain showed only partial degradation (about 70%). Degradation by halophilic consortia was greater than 50%. Three of the more effective microorganisms (Halobacterium piscisalsi, Haloarcula argentinensis and Salicola sp.) were selected for further analysis of the degradation pathways by gas chromatography, which allowed the assessment of both aromatic and aliphatic hydrocarbons and the identification of the byproducts.