Potencial de cianobactérias na bioindicação e biodegradação de ambientes contaminados por naftaleno no Brasil e na Antártica

• Autor(a) principal: Corrêa, Débora Machado
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2572
• topic: Cianobactérias; Biofilmes; Hidrocarbonetos; Bioindicação; Biorremediação; Cyanobacteria; Biofilms; Hydrocarbons; Bioindication; Biorremediation; CNPQ::CIENCIAS BIOLOGICAS::BOTANICA::BOTANICA APLICADA

Cyanobacteria were isolated from two sites with a different hyrocarbon contamination history. In the first case, biofilms of cyanobacteria were collected in a drainage system, from a gas station of Viçosa City, MG. From these biofilms, the one presenting the greater cyanobacterial diversity was selected to be enriched (using the AA4 liquid medium). Both the integral biofilm (mixed treatment), and a monoclonal culture of Phormidium sp. (monoclonal treatment), which was isolated from the integral biofilm, were tested for [C14] naphthalene biodegradation ability, under photoauthotrophic conditions, and at temperature of 20 ± 1ºC. Mixed treatment as well as monoclonal treatment showed to be able to readily mineralize naphthalene, in the ratio of 28 and 22,5%, respectively, during a experimental period of fifteen days. For both, the cumulative naphthalene degradation plateau was reached around the fourth day of the experiment. Two hypotheses were considered trying to explain the premature plateau degradation: (1) by naphthalene exhaustion, since 14CO2 losses were not registered by the respirometric system used in the test; (2) by nutrient depletion, since there was no soil correction in the experiment. In that case, the only inorganic nutrient source applied was provided by the culture medium (1 mL) used to ressuspend the inoculum. The integral biofilm and the monoclonal culture of Phormidium sp. were considered to have potencial to degrade naphthalene. It was suggested that they could be indicated for future biorremediation experiments of hydrocarbon contaminated sites. On the second case, a cyanobacteria from the genus Phormidium sp. ANT 01 was collected and isolated from antarctic soils without a hydrocarbon contamination history. Phormidium sp. ANT 01 was selected for another experiment using [C14] naphthalene biodegradation, under photoauthotrophic conditions, and at temperture of 15 ± 1ºC. The results showed that the monoclonal culture of Phormidium sp. ANT 01 were not able to degrade naphthalene, when compared with the abiotic treatment (control). A second experiment was carried out to test the biomass production of Phormidium sp. ANT 01 under naphthalene conditions. The exposure of Phormidium sp. ANT 01 to the naphthalene at concentration of 66,67 μg.L-1 caused a inibitory effect on the growth of the organisms around 37%. By reason of its great distribution and abundance in soils of Admiralty Bay, Antarctic, and its sensibility under low naphthalene concentrations, Phormidium sp. ANT 01 showed potencial to be used as a bioindicator of hydrocarbon contaminated soils of this region.