Caracterização morfológica e molecular de cianobactérias da Antártica Marítima e potencial para biodegradação e bioindicação em ambientes contaminados por hidrocarbonetos

• Ano de defesa: 2012
• Autor(a) principal: Corrêa, Débora Machado
• Orientador(a): Schaefer, Carlos Ernesto Gonçalves Reynaud
• Banca de defesa: Silva, Silvana de Queiroz , Fernandes, Péricles Leonardo
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Botânica
• Departamento: Botânica estrutural; Ecologia e Sistemática
• País: BR
• Palavras-chave em Português: Cianobactérias; Antártica; Hidrocarbonetos; Biodegradação; Bioindicação
• Palavras-chave em Inglês: Cyanobacteria; Antarctic; Hydrocarbon; Biodegradation; Bioindication
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::BOTANICA
• Link de acesso: http://locus.ufv.br/handle/123456789/367

The analyses of cyanobacterial communities in soil, lakes and glacial streams samples of three areas within the Maritime Antarctic domain revealed 37 cyanobacterial taxa, with majority belonging to Oscillatoriales Order. The most widespread organisms belonged to genera Phormidium spp,. Leptolyngbya spp. and Nostoc spp.. Seventeen strains were isolated and kept in culture into the Banco de Algas do Laboratório de Ficologia DBV/UFV. Given the concern about the impact of the Antarctic environmental contamination with petroleum hydrocarbons on microbial communities, we tested the effect of three aromatic hydrocarbons on the growth of Phormidium autumnale UFV-ANT01. Toxicological data such as NOEC, EC20 and EC50 were estimated. The toxicity observed on the growth of cyanobacteria tested followed the order: α-benzo-pyrene> anthracene> naphthalene. Concentrations of benzo-α-pyrene four hundred and fifty times smaller than those of naphthalene are sufficient to cause the same toxicity on Phormidium autumnale UFV-ANT01. Populations of cyanobacteria can be a useful tool for the biomonitoring of areas contaminated with hydrocarbons.Bioremediation can be a low cost and ecologic alternative to solve hydrocarbon contamination problems in Antarctic soils. The ability of three cyanobacterial strains in degrading [14C]naphthalene was tested under 15°C. Cyanobacterial lineages Phormidium autumnale UFV-ANT01, Nostoc sp. UFV-ANT23 and Tolypothrix sp. UFV-ANT22 was selected due its important contribution to Antarctic microbial mats. Cyanobateria was investigated in monoclonal cultures and in consortia with heterotrophic bacteria, in comparison with bacterial and abiotic controls. After 200 hours of exposure to labeled hydrocarbons, treatments corresponding to consortia proved to be more effective in [14C]naphthalene than the monoclonal treatments and controls. Cumulative mineralization rates were 42%, 39% and 32%, for Nostoc consortia, Phormidium consortia and Tolypothrix consortia respectively, while bacterial control mineralized 11% of the added hydrocarbon. Monoclonal treatments degraded 2,6 to 4,2% of naphthalene added and were considered less effective than bacterial control, but did not differ from abiotic control (1,9%). Degradation kinetics was similar to those previously reported by other authors for low hydrocarbon concentrations models, in which microbial hydrocarbon attack begins shortly after the contaminant was added to treatments. The rates of hydrocarbon degradation observed to consortia treatments were superior to the sum of individual monoclonal ones and the bacterial control, indicating that cyanobacteria had played a important role in the biodegradation process, providing moisture, nutrients, oxygen and immobilizating the biodegraders microorganisms.