Petroleum hydrocarbons are recalcitrant contaminants that have various impacts on the natural ecosystem. Microorganisms have been widely used in recent years to remove the hydrocarbons that are present in crude oil. The objective of this research was to isolate and select microorganisms that have the potential to degrade hydrocarbons present in mangrove sediments. In present study, we have isolated fungi from clean sediment contaminated with different fractions (i.e., saturated hydrocarbons, aromatic, and no hydrocarbon compounds (NSO)) of two types of oil. There were two types of oxidation tests were performed: one in multi well plates and the other in stirring and temperature control. Screening tests were conducted to detect the biodegradation of petroleum fractions with 72 fungal isolates over a period between 12 and 48 hours. With the two oxidation tests, the 2,6-dichlorophenol-indo phenol (DCPIP) indicator made it possible to select fungi with the potential to degrade the three main fractions of oil in the Reconcavo and Campos Basins. It was observed that the fungal isolates in the cleaned sediment were able to oxidize the three fractions of both types of oil. It was also concluded that some isolated strains oxidize oil faster and more efficiently than others. The formation of a consortium with the isolated consortium was a potential for the increase of the degradation of oil in the environment.
Bioremediation is a technique applied to several environmental impacts, among which the ones generated by petroleum derivatives, through the introduction of microorganisms into the environment, or creating optimal conditions for them to develop. The present study aimed to evaluate the degradation of saturated hydrocarbons through the biostimulation technique in the mangrove sediment impacted by petroliferous activities, testing the potentiality of two fertilizers (NPK and OSMOCOTE) as accelerating agents of the biodegradation of petroleum components, under experimental conditions. In order to understand the bioremediation process it was used the quantification of nutrient contents, the percent of saturated, aromatic and NSO hydrocarbons, and the behavior of saturated compounds along the entire experiment, besides the monitoring of physical and chemical parameters. Chromatographic profiles characterized a major degradation of saturated hydrocarbons at the units with NPK, presenting a better efficiency of this fertilizer in the tested biostimulation process
Bioassays with the marine copepod Tisbe biminiensis were used to evaluate the efficiency of three bioremediation treatments on oil contaminated sediments. Two biostimulation treatments (adding NPK and OSMOCOTE fertilizers) and a natural attenuation treatment (experimental control, without fertilizers) were evaluated. The addition of NPK fertilizer had a strong lethal effect on T. biminiensis females probably associated to ammonium compounds, but this effect disappeared after 15 days. The OSMOCOTE releases nutrients in a gradual manner and as such, had no lethal effect on T. biminiensis females. In the natural attenuation treatment, the fecundity of T. biminiensis increased 200% and this indicates that natural attenuation treatment effectively attenuated the sub-lethal toxicity. Biostimulation treatments were not more efficient in obtaining lower toxicity levels of oil contaminated sediment compared to natural attenuation as the recovery of the endpoint affected by contamination (fecundity) increased at the same rate in the 3 treatments over time. In conclusion, adding fertilizers with high ammonium compound concentrations and rapid release is not recommended as a bioremediation treatment in mangroves.
The purpose of this work was to propose sustainable solutions for advanced oil recovery by evaluating the ability of the bacterium Pseudomonas sp. in the biotransformation of alkanes, in addition to determining strain growth patterns under extreme conditions. For this, the work was initially carried out under laboratory conditions, in which the crude oil was fractionated to obtain the saturated fraction used in the experiment. The bacterial tolerance to salinity and temperature was also tested to determine the experimental conditions and set up the experiment in regard to these parameters. Additionally, an experiment was performed to produce a biosurfactant through biostimulation. The biotransformation experiment consisted of a triplicate with treatment and a control. For treatments, Erlenmeyers flasks received 100 mL of broth containing the biosurfactant, 10 g (10%) of NaCl, 3% of the strain and 1% of the saturated fraction. Erlenmeyer flasks were incubated at 40 °C and 180 rpm for 18 days with periodic analysis. The results initially showed the bacteria exhibited better tolerance at a temperature of 40 °C, and there was no significant change for the different salinities, which was a nonlimiting parameter. For the final experiment, the bacterial growth analysed by Optical Density (OD). exhibited a low variation, in which the lowest point was in T18 with an absorbance of 0.115 and the highest point was in T6 with an absorbance of 0.149. In the qPCR analysis of the bacterial population, the pattern found was similar to the optical density results, with low variation; the lowest number of copies of the 16S rRNA gene (6.66x 103) was found in T0 and the highest number was found in T12 (7.86x 103). For biotransformation analysis, time 6 was observed to have the highest rate, with 54% oil recovery (C30), followed by 52% (C31) and 51% (C29).
Fungi are excellent producers of extracellular enzymes. Therefore, the present study aimed to investigate the screening of marine fungi, which are laccase and manganese peroxidase potential producers, in solid fermentation for future applications in bioremediation processes of contaminated sites. For this purpose, twolevel factorial planning was adopted, using time (6 and 15 days) and the absence or presence of oil (0 and 1%) as factors. The semi-quantitative evaluation was carried out by calculating radial growth, enzyme activity and enzyme index by measuring phenol red or syringaldazine oxidation halo. The results showed that all the studied strains showed a positive result for manganese peroxidase production, with an enzymatic activity in solid medium less than 0.61, indicating a strongly positive activity. Through the enzyme index, the study also showed prominence for Penicillium sp. st rains, with values > 2. The enzyme index increase in oil presence and the inexpressive use of the genera studied for ligninolytic enzymes production from crude oil demonstrated these data importance for fermentative processes optimization. Considering the ability of these strains to develop into recalcitrant compounds and the potential for manganese peroxidase production, they are indicated for exploitation in various bioremediation technologies, as well as other biotechnological applications.
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