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Detoxification of petroleum and diesel oil by microbial consortium from marine environment

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Author(s):
Lídia de Azevedo Duarte
Total Authors: 1
Document type: Master's Dissertation
Press: Rio Claro. 2016-07-12.
Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Rio Claro
Defense date:
Advisor: Lara Durães Sette
Abstract

The high industrial activity and the use of petroleum as the current primary energy resource are some of the factors that contribute to the release of petrochemical products in the environment. Marine environments are susceptible to contamination by petroleum due to its close relationship with the oil industry. Micro-organisms derived from these environments have the potential to act in bioremediation under these conditions. Thus, the aim of this study was to analyze the detoxification and degradation of crude oil and diesel samples by ten microbial consortia composed with the following microorganisms in combinations: four ligninolytic fungi (basidiomycetes and not basidiomycetes) isolated from marine invertebrates, two isolated from oil reservoir (off-shore), two marine lipolytic yeast from Antarctic and a marine lypolitic fungus from the Brazilian coast. The evaluation of detoxification was performed by acute toxicity analysis with Microtox (Vibrio fisheri) and the microcrustacean Artemia sp. The consortium composed by Aspergillus sclerotiorum CBMAI 849, Cladosporium cladosporioides CBMAI 857, Bacillus sp. CBMAI 707 e Cryptococcus laurentii CRM 707, showed 46% and 60% of Artemia sp. survivors after incubation for 21 days with diesel oil and petroleum, respectively. These results corroborate the microtox data, which showed a decrease in toxicity when incubated with diesel, justifying the selection of this consortium to the next steps of the study. The experimental design allowed us to determine optimal conditions of temperature and agitation to the selected consortium. Two Plackett-Burman experiments were carried out and the best assays were validated experimentally. Validation tests confirmed the potential of the consortium to detoxifify the pollutants. The experimental design enabled the increasing in diesel concentration and the use of only malt extract as additional source, reducing the cost of the process. For petroleum, results after 7 days of incubation showed the possibility of reducing the treatment time. Laccase, Manganese Peroxidase and Lignin Peroxidase activities were not detected in the validation experiments. The lipase activity was higher in the assays with petroleum and diesel oil in comparison with the assays without the pollutants, indicating that there was an induction on the enzymatic activity by the pollutants. The GC/MS analysis showed changes in the chromatographic profiles of petroleum and diesel oil after incubation with the micro-organisms. Results from the presente work, highlight the relevance of marine-derived micro-organisms in the detoxification of environmental pollutants and stimulate new studies in the field of marine consortium application, the enzymes involved in the process and the evaluation of gene expression by using metatranscriptomic approach. (AU)

FAPESP's process: 14/13205-2 - Detoxification and degradation of petroleum and diesel oil by microbial marine consortia
Grantee:Lidia de Azevedo Duarte
Support Opportunities: Scholarships in Brazil - Master