RESUMO
Bioremediation of marine environment could be the response to oil spills threats. In the present study the fungal community from a Mediterranean marine site chronically interested by oil spills was investigated. Sixty-seven taxa were isolated from water sample and 17 from sediments; for many of the identified species is the first report in seawater and sediments, respectively. The growth of 25% of the fungal isolates was stimulated by crude oil as sole carbon source. Four strains were selected to screen hydrocarbons degradation using the 2,6-dichlorophenol indophenol (DCPIP) colorimetric assay. A. terreus MUT 271, T. harzianum MUT 290 and P. citreonigrum MUT 267 displayed a high decolorization percentage (DP≥68%). A. terreus displayed also the highest decreases of hydrocarbons compounds (up to 40%) quantified by gas-chromatography analysis. These results suggest that the selected fungi could represent potential bioremediation agents with strong crude oil degradative capabilities.
Assuntos
Fungos/classificação , Poluição por Petróleo , Água do Mar/microbiologia , Biodegradação Ambiental , Fungos/isolamento & purificação , Hidrocarbonetos/metabolismo , Região do Mediterrâneo , Petróleo/metabolismoRESUMO
The fate of hydrocarbon pollutants and the development of oil-degrading indigenous marine bacteria in contaminated sediments are strongly influenced by abiotic factors such as temperature, low oxygen levels, and nutrient availability. In this work, the effects of different biodegradation processes (bioremediation) on oil-polluted anoxic sediments were analyzed. In particular, as a potential bioremediation strategy for polluted sediments, we applied a prototype of the «Modular Slurry System» (MSS), allowing containment of the sediments and their physical-chemical treatment (by air insufflations, temperature regulation, and the use of a slow-release fertilizer). Untreated polluted sediments served as the blank in a non-controlled experiment. During the experimental period (30 days), bacterial density and biochemical oxygen demand were measured and functional genes were identified by screening. Quantitative measurements of pollutants and an eco-toxicological analysis (mortality of Corophium orientale) were carried out at the beginning and end of the experiments. The results demonstrated the high biodegradative capability achieved with the proposed technology and its strong reduction of pollutant concentrations and thus toxicity (AU)
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Assuntos
51929/métodos , Poluentes Químicos da Água/análise , /análise , Poluição por Petróleo/análise , Terapia com Luz de Baixa Intensidade , Sedimentos Geológicos/microbiologia , Biodegradação AmbientalRESUMO
Microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS2003) on microbial community dynamics. An experimental seawater microcosm, supplemented with crude oil and EPS2003 (SW+OIL+EPS2003), was monitored for 15 days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out during all experimentation period. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil degradation was monitored by GC-MS analysis. Bioemulsificant addition stimulated an increase of the total bacterial abundance, change in the community structure and activity. The bioemulsificant also increased of 5 times the oil biodegradation rate. The data obtained from microcosm experiment indicated that EPS2003 could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process.