Bioremediation of oil-contaminated field by two Pseudomonas aeruginosa strains / 生物工程学报

We studied the remediation of petroleum-contaminated soils. Two Pseudomonas aeruginosa strains were screened from soil samples in the mine environment. The degradation rate of crude oil was 95.67% after 10 days by mixed culture of the two strains, which was 32% higher than that of single bacterium. It means that the two bacteria had synergistic effect on degrading crude oil. Based on the result, bacterial agent was prepared, and the oil pollution sites were artificially constructed to simulate the degradation of crude oil under different operating conditions. During the experiment, the petroleum hydrocarbon content of the sites after treating with the bacterial agent, decreased obviously in 60 days. The content decreased to among 0.1% and 0.3% from the initial 0.8% per gram of soil. Then, the site with organic manure as supplemental source of carbon and nitrogen had the highest degradation rate of 85.28%, compared to that without adding bacterial agent of only 25.85%.

Parámetros hematológicos y de estrés oxidativo en pingüinos de Magallanes rehabilitados por contaminación con petróleo / Blood and oxidative stress parameters of oil-spill rehabilitated magallanic penguins

Los pingüinos de Magallanes son entre las aves marinas, la especie más afectada por la contaminación con petróleo en Chubut y Santa Cruz. Una de las consecuencias adversas de la exposición a hidrocarburos y otros contaminantes es el aumento de los niveles celulares de especies reactivas del oxígeno o estrés oxidativo, considerados herramientas útiles como biomarcadores del impacto de la exposición a contaminantes químicos peligrosos. El objetivo de este trabajo fue evaluar parámetros hematológicos y marcadores de estrés oxidativo durante la rehabilitación de tres pingüinos empetrolados provenientes del Área Natural Protegida Punta Tombo, Chubut, Argentina. Se tomaron tres muestras de sangre por individuo: la primera muestra al arribo de los pingüinos al centro de rehabilitación, la segunda una semana después y una última muestra antes de ser liberados. Se obtuvieron la cantidad total de leucocitos, la razón heterófilos/linfocitos, el hematocrito y las concentraciones de glucosa y de proteínas totales. Se analizó la actividad de la enzima catalasa, responsable de la degradación del peróxido de hidrógeno, los niveles de tioles totales no proteicos y el daño a lípidos evaluando las especies reactivas al ácido tiobarbitúrico, como indicadores de estrés oxidativo. El estudio se complementó con la obtención del peso de los pingüinos. En general, los parámetros medidos, aumentaron o se mantuvieron constantes desde la primera toma de muestra hasta la última. Si bien algunas de las variables para cada pingüino se comportaron diferentes durante el tratamiento, en general se observó una tendencia a normalizarse hacia el momento de su liberación. Se concluye que los pingüinos se liberaron en buen estado físico luego de la rehabilitación.

Magellanic penguins are among the most affected seabirds by oil contamination in Patagonia. Hydrocarbons and other pollutants cause an increase in the cellular levels of reactive oxygen species that lead oxidative stress and in this way, the evaluation of oxidative stress parameters could be useful tools as biomarkers to evaluate the exposure to hazardous chemical contaminants. The aim of the present work was to evaluate hematological parameters and oxidative stress biomarkers during the rehabilitation of three oil-spill penguins from Punta Tombo Natural Protected Area in Chubut, Argentina. Three blood samples were taken from each individual, the first sample was obtained at arrival of penguin to the rehabilitation center, the second one was the following one week and last sample was taken before animals were freed. Hematocrit, white blood cell count, heterophil/ lymphocyte ratio as a measure of stress, and concentrations of glucose and total proteins were determined. The thiobarbituric acid reactive species, a well-established method for monitoring lipid peroxidation, the activity of catalase enzyme (involved in the catabolism of hydrogen peroxide) and the thiol levels were evaluated as oxidative stress indicators. In general, the measured parameters remained constant or increased their values from the first to the last blood sampling. While some of the variables for each penguin behaved differently during treatment, generally they tended to normalize when penguins were released. We conclude that penguins were released in good physical condition after rehabilitation.

Biodegradation of 2,4'-dichlorobiphenyl, a congener of polychlorinated biphenyl, by Pseudomonas isolates GSa and GSb.

Biodegradation of 2,4'-dichlorobiphenyl (2,4 CB), by two isolates of Pseudomonas (GSa and GSb) was compared using GC-MS. Transformer oil polluted soil was used for the isolation of 2,4 CB degrading bacteria. GC-MS analysis of the solvent extracts obtained from Pseudomonas sp. GSa spent culture indicated the presence of Phenol 2,6-bis (1,1-dimethyl)-4-methyl (C15H24O). Further, the enzyme analysis of the cell free extracts showed the presence of 2,4'-dichlorobiphenyl dehalogenase (CBD), 2,4'-dichlorobiphenyl-NADPH-oxido-reductase (2,4 CBOR) and 2,3-dihydro-xybiphenyl-NADPH-oxido-reductase (2,3 DHOR) with specific activity of 6.00, 0.4 and 0.22 μmol/min/mg of protein, suggesting that dechlorination as an important step during 2,4 CB catabolism. Further, the cell free extract of GSb showed only 2,4'-dichlorobiphenyl-NADPH-oxido-reductase (2,4 CBOR) and 2,3-dihydroxybiphenyl-NADPH-oxido-reductase (2,3 DHOR), with specific activity of 0.3 and 0.213 μmol/min/mg of protein, suggesting attack on non-chlorinated aromatic ring of 2,4 CB, releasing chlorinated intermediates which are toxic to the environment. Although, both the isolated bacteria (GSa and GSb) belong to Pseudomonas spp., they exhibited different metabolic potential.

Microbial Communities and Hydrocarbon Degradation in Oil-contaminated Seawater / 微生物学通报

Nowadays,oil-pollution of seawater in the world has severely threatened the security of sea entironment.Bioremediation offers one available option for an oil spill response.The aspects as follows are introduced some evolvement of microbial ecology,including new method of survey of microbial diversity without cultivation,new isolated method and the properties of main hydrocarbon degradated strain.But we have little or no understanding of the vast majority of marine bacteria that remain uncultured,and more efforts should be made to improve current methods for isolating oil-degrading or oil-emulsifying bacteria,not only for assessing the fate and effects of the spilled oil,but also for isolating novel bacteria that would be useful for the petroleum industry.