In situ bioremediation of petroleum hydrocarbon–contaminated soil: isolation and application of a Rhodococcus strain / Biorremediación in situ de suelos contaminados con hidrocarburos de petróleo: aislamiento y aplicación de una cepa de Rhodococcus

Due to low consumption and high efficiency, in situ microbial remediation of petroleum hydrocarbons (PHs)-contaminated sites in in-service petrochemical enterprises has attracted more and more attention. In this study, a degrading strain was isolated from oil depot–contaminated soil with soil extract (PHs) as the sole carbon source, identified and named Rhodococcus sp. OBD-3. Strain OBD-3 exhibited wide adaptability and degradability over a wide range of temperatures (15–37 °C), pH (6.0–9.0), and salinities (1–7% NaCl) to degrade 60.6–86.6% of PHs. Under extreme conditions (15 °C and 3–7% salinity), PHs were degraded by 60.6 ± 8.2% and more than 82.1% respectively. In OBD-3, the alkane monooxygenase genes alkB1 and alkB2 (GenBank accession numbers: MZ688386 and MZ688387) were found, which belonged to Rhodococcus by sequence alignment. Moreover, strain OBD-3 was used in lab scale remediation in which the contaminated soil with OBD-3 was isolated as the remediation object. The PHs were removed at 2,809 ± 597 mg/kg within 2 months, and the relative abundances of Sphingobium and Pseudomonas in soil increased more than fivefold. This study not only established a system for the isolation and identification of indigenous degrading strains that could efficiently degrade pollutants in the isolated environment but also enabled the isolated degrading strains to have potential application prospects in the in situ bioremediation of PHs-contaminated soils.(AU)

Population dynamics and crude oil degrading ability of bacterial consortia of isolates from oil-contaminated sites in Nigeria / Dinámica de la población y capacidad de degradación del petróleo crudo de consorcios bacterianos de aislamientos de sitios contaminados con petróleo en Nigeria

Application of bacterial consortium of hydrocarbon degraders to crude oil–contaminated site can enhance bioremediation. This study evaluated the population dynamics and crude oil degradation abilities of various consortia developed from bacterial strains isolated from crude oil–contaminated sites using crude oil–supplemented Bushnell Haas media. Each consortium consisted of three bacterial strains and was designated as Consortium A (Serratia marcescens strain N4, Pseudomonas aeruginosa strain N3R, Pseudomonas aeruginosa strain W11), B (Pseudomonas aeruginosa strain N3R, Pseudomonas aeruginosa strain W11, Pseudomonas protegens strain P7), C (Serratia marcescens strain N4, Pseudomonas aeruginosa strain W11, Pseudomonas protegens strain P7), and D (Pseudomonas aeruginosa strain W15, Providencia vermicola strain W8, Serratia marcescens strain W13). There was progressive decline in the populations of Serratia marcescens strains in the consortia as the incubation period progressed. This may have led to reduction in their synergistic contribution and, subsequently, total degradation ability of crude oil by the consortia. The gravimetric analyses showed that Consortium D produced the highest % crude oil degradation of 29.66% compared to Consortia A, B, and C with 23.73%, 11.86%, and 19.49% respectively. Based on gas chromatography–mass spectrometry analyses, Consortium D produced the highest percentage total petroleum hydrocarbon degradation of 73.65% compared to 68.24%, 68.94%, and 69.19% produced by Consortia A, B, and C respectively. The biodegradation potential of Consortium D also demonstrates the significance of using isolates from the same isolation site in development of consortium for bioremediation.(AU)

Entender la naturaleza para crear una industria. El petróleo en la exploración de John McLeod Murphy en el istmo de Tehuantepec, 1865 / Fathom the nature to create an industry: oil survey during the exploration of John McLeod Murphy in the Isthmus of Tehuantepec, 1865

En 1851, John McLeod Murphy fue el oficial inferior de la Armada estadounidense encargado de redactar el informe hidrográfico en la expedición científica en el istmo de Tehuantepec, dirigida por el Mayor Barnard. Durante su exploración, encontró varios criaderos y pozas de petróleo. Años más tarde, en Nueva York, Murphy fue espectador interesado de la explosión de riqueza generada por la extracción del petróleo; el decidió volver a Tehuantepec para explorar más detenidamente las zonas. Los resultados de su visita se plasmaron, en 1865, en un importante estudio de factibilidad acerca de la posibilidad de emprender la explotación petrolífera en la región. Su estudio constituye la primera combinación de exploración geográfica, medición topográfica, interpretación geológica y logística comercial del petróleo mexicano; y representa una fuente hasta aquí no conocida y analizada (AU)

In 1851, John McLeod Murphy was the junior officer of the U.S. Navy in charge of drafting the hydrographic report during the scientific expedition of the Isthmus of Tehuantepec, directed by Major Barnard. During his survey Murphy observed the oil springs and lakes scattered around the Atlantic Plains of the Isthmus. Years later in New York, Murphy was observing with interest the massive wealth generated by petroleum; he decided to move again to the Isthmus to explore more thoroughly the area. In 1865 Murphy prepared an important feasibility study on the possibility to build oil settlements in South Veracruz. Geographic survey, topographic measurements, geological interpretation, and logistic, are some of the elements proposed by Murphy to describe the making of oil in the uncontaminated and wild Mexican natural landscapes (AU)

Impacto de las actividades antrópicas derivadas de la industria petrolera en relación con la presencia de metales pesados en la ganadería bovina colombiana / Impact of human activities deriving from the oil industry in connection with the presence of heavy metals in cattle Colombian

La región del Magdalena medio es una zona de actividad industrial-minera con exploraciones y refinación de hidrocarburos. Por ello los animales que viven en esta área geográfica son afectados por la presencia de contaminantes, especialmente metales pesados. En este trabajo se estudiaron 40 animales adultos, sacrificados en el matadero de Barrancabermeja, procedentes de explotaciones bovinas cercanas a industrias con actividad petrolífera. Se determinó la presencia de plomo, cadmio, molibdeno y zinc en hígado, riñón, músculo y piel mediante espectrofotometría de absorción atómica y se compararon los resultados obtenidos con los límites máximos permisibles establecidos por la Unión Europea y el Codex Alimentarius [1,2]. Se encontró mayor concentración de todos los metales en Barrancabermeja excepto el Zn que presentó mayores niveles en Yondó. Un número importante de muestras hepáticas (90 y 50%), renales (75 y 15%) y musculares (85 y 90%) de ambas localizaciones superaron los valores permisibles de Pb tanto del Codex Alimentarius, como de la Unión Europea. Situación similar sucede con el Cd en Barrancabermeja, superando en el 85%, el 10% y la totalidad (100%) los valores permitidos por la Unión Europea en hígado, riñón y músculo respectivamente, mientras que en Yondó, 65% de las muestras hepáticas y todas las muestras musculares superan esos mismos límites. Por ello podemos concluir que el consumo de carne y vísceras de bovinos que pastorean en el Magdalena Medio Colombiano, representa un grave riesgo para la salud humana como consecuencia de su alto grado de contaminación con metales pesados (AU)

Middle Magdalena region is an area with an industrial-mining with exploration and refining of oil. Therefore the animals that live in this geographical area are affected by the presence of pollutants, especially heavy metals. In this study 40 adult animals slaughtered in the abattoir in Barrancabermeja, from bovine holdings nearby industries with petroleum extraction activities were studied. The presence of lead, cadmium, molybdenum and zinc in liver, kidney, muscle and skin was determined by atomic absorption spectrophotometry and the results obtained with the limits set by the European Union and the Codex Alimentarius were compared [1,2]. Higher concentration of all metals was found in Barrancabermejaexcept Zn presented higher levels in Yondó. A significant number of liver samples (90 and 50%), kidney (75 and 15%) and muscle (85 and 90%) of both locations exceeded the permissible values of Pb both the Codex Alimentarius and the European Union. A similar situation occurs with cd in Barrancabermeja, exceeding 85%, 10%and all (100%) values allowed by the European Union in liver, kidney and muscle respectively, while in Yondó, 65% of samples liver and muscle samples exceed all those same limits. Therefore we can conclude that the consumption of meat and offal from cattlegrazing in the Middle Magdalena Colombian, represents a seriousrisk to human health as a result of its high degree of contamination with heavy metals (AU)

Production of two novel laccase isoforms by a thermotolerant strain of Pycnoporus sanguineus isolated from an oil-polluted tropical habitat

A thermotolerant and halotolerant strain of Pycnoporus sanguineus was isolated from an oil-polluted site in a tropical area located in Veracruz, Mexico. This strain was able to grow at 47 degrees C and in culture medium containing 500 mM NaCl. The strain was also tolerant to the presence of 30,000 ppm of crude Maya oil. A 68-kDa protein purified from submerged cultures exhibited laccase activity towards 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), guaiacol, syringaldazine, and o-dianisidine, for which it presented the highest affinity (Km = 43 microM). Two-dimensional gel electrophoresis analysis showed that, unusual for laccases, the enzyme has two active isoforms, with isoelectric points of 7.00 and 7.08. The purified enzyme showed high thermostability, retaining 40% of its original activity after 3 h at 60 degrees C. This property seems to correlate with a long «shelf-life», given that at 40 degrees C enzyme activity was only gradually lost over a 5-day period incubation. Both the fungus and its laccase are likely to have high potential for biotechnological applications (AU)

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La exposición a las mareas negras y sus efectos en la salud / Health effects of exposure to oil spills

El naufragio del petrolero Prestige frente a las costas gallegas no sólo supuso el mayor desastre ecológico en la historia de nuestro país, sino que también propició la exposición de miles de personas que participaron en la limpieza de las zonas contaminadas a compuestos potencialmente tóxicos para la salud. Teniendo en cuenta que la vía respiratoria es una de las principales puertas de entrada de estos compuestos en el organismo, los posibles efectos de estos vertidos preocupan especialmente a los profesionales que nos dedicamos a las enfermedades respiratorias. Sin embargo, la información clínica que tenemos es manifiestamente insuficiente. Por tal motivo se ha elaborado esta revisión. En ella se analizan los estudios científicos realizados a propósito de otros naufragios de petroleros. Finalmente se exponen los datos clínicos y epidemiológicos de las investigaciones publicadas hasta la fecha con ocasión del hundimiento del buque Prestige

The sinking of the oil tanker Prestige off the coast of Galicia was not only the worst ecological disaster ever to affect Spain, it also led to thousands of people who participated in the cleanup of the contaminated areas being exposed to potentially dangerous toxic substances. As the airway is one of the principal routes of entry into the body of these toxic compounds, the possible effects of exposure to such spills is of particular interest and concern to respiratory specialists. The paucity of clinical information available on the subject was the motive for this paper, which reviews the scientific studies undertaken in the aftermath of other accidents involving oil tankers and concludes with a summary of the clinical and epidemiological data published to date on the Prestige oil spill

Presence of opportunistic oil-degrading microorganisms operating at the initial steps of oil extraction and handling / Presencia de microorganismos oportunistas degradadores de petróleo en la extracción y manipulación iniciales de petróleo

Hydrocarbon-degrading microorganisms from natural environments have been isolated and identified using culture-dependent or molecular techniques. However, there has been little research into the occurrence of microorganisms incorporated into crude oil in the initial steps of extraction and handling, which can reduce the quality of stored petroleum. In the present study, a packed-column reactor filled with autoclaved perlite soaked with crude oil was subjected to a continuous flow of sterile medium in order to determine the presence of potential hydrocarbon degraders. Microorganisms developed on the surface of the perlite within a period of 73 days. DNA was extracted from the biofilm and then PCR-amplified using 16S rRNA bacterial and archaeal primers and 18S rRNA eukaryotic primers. No amplification was obtained using archaeal primers. However, denaturing gradient gel electrophoresis (DGGE) revealed the presence of unique bands indicating bacterial and eukaryotic amplification. Excision of these bands, sequencing, and subsequent BLAST search showed that they corresponded to Bacillus sp. and Aspergillus versicolor. The fungus was later isolated from intact perlite in agar plates. A bacterial clone library was used to confirm the presence in the biofilm of a unique hydrocarbon-degrading bacterium closely related to Bacillus sp. Analysis of the petroleum components by gas chromatography showed that there n-alkanes, aromatic hydrocarbons, and carbazoles were degraded (AU)

Algunos autores han aislado e identificado microorganismos degradadores de petróleo utilizando técnicas moleculares o dependientes de cultivo. Sin embargo, se ha investigado poco la presencia de microorganismos que entran en contacto con el petróleo en las fases iniciales de su extracción y manipulación, circunstancia que puede reducir la calidad del petróleo almacenado. Mediante un reactor con una columna cargada con perlita esterilizada en autoclave y empapada de petróleo, y sujeto a un flujo continuo de medio estéril, determinamos la presencia de posibles degradadores de hidrocarburos. En la superficie de la perlita se desarrollaron microorganismos en un período de 73 días. Se extrajo el DNA del biofilm, y se amplificó por PCR con cebadores para el 16S rRNA de bacterias y arqueas y con cebadores para el 18S rRNA de eucariotas. No se obtuvo ampliación del DNA de arqueas, pero el análisis por electroforesis en gel con gradiente desnaturalizante (DGGE) reveló la presencia de bandas únicas en la amplificación de bacterias y eucariotas. La escisión de estas bandas, la secuenciación y la subsiguiente búsqueda en BLAST demostraron que correspondían a Bacillus sp. y a Aspergillus versicolor. El hongo fue aislado posteriormente en placas de agar a partir de perlita intacta. También se llevó a cabo una biblioteca genética bacteriana, que confirmó la presencia de una única bacteria degradadora de petróleo en el biofilm, muy próxima a Bacillus sp. El análisis de los componentes del petróleo por cromatografía de gases mostró que había habido degradación de n-alcanos, hidrocarburos aromáticos y carbazoles (AU)

El impacto en la salud humana de la catástrofe del Prestige / The impact of the Prestige disaster on human health

La mayor catástrofe ambiental de la historia de España propició una renovación de la conciencia social sobre las estrechas relaciones que existen entre el estado del medio ambiente y la salud de las personas. Sin embargo, la salud de las poblaciones más directamente afectadas por el vertido de fuel no fue inicialmente la preocupación principal de las autoridades políticas. Los principales objetivos de este trabajo son, en primer lugar, comentar sucintamente algunas de las actuaciones más destacadas llevadas a cabo por diferentes actores sociales y, en segundo lugar, sugerir cuáles podrían ser los principales objetivos y características de los estudios epidemiológicos que es necesario realizar para poder valorar con fundamento racional el posible impacto del accidente sobre la salud de los trabajadores, voluntarios y residentes en las zonas más afectadas por el vertido. Los autores esperan que en un futuro cercano se podrán valorar científicamente los resultados y las implicaciones de diversos estudios (epidemiológicos y de otra índole) correctamente diseñados y ejecutados. (AU)

Vertidos de petróleo y salud pública / Oil spills and public health

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Bioremediation of oil by marine microbial mats / La biorremediación del petróleo por la acción de los tapetes microbianos marinos

Cyanobacterial mats developing in oil-contaminated sabkhas along the African coasts of the Gulf of Suez and in the pristine Solar Lake, Sinai, were collected for laboratory studies. Samples of both mats showed efficient degradation of crude oil in the light, followed by development of an intense bloom of Phormidium spp. and Oscillatoria spp. Isolated cyanobacterial strains, however, did not degrade crude oil in axenic cultures. Strains of sulfate-reducing bacteria and aerobic heterotrophs were capable of degrading model compounds of aliphatic and aromatic hydrocarbons. Results indicate that degradation of oil was done primarily by aerobic heterotrophic bacteria. The oxygenic photosynthesis of oil-insensitive cyanobacteria supplied the molecular oxygen for the efficient aerobic metabolism of organisms, such as Marinobacter sp. The diurnal shifts in environmental conditions at the mat surface, from highly oxic conditions in the light to anaerobic sulfide-rich habitat in the dark, may allow the combined aerobic and anaerobic degradation of crude oil at the mat surface. Hence, coastal cyanobacterial mats may be used for the degradation of coastline oil spills. Oxygen microelectrodes detected a significant inhibition of photosynthetic activity subsequent to oil addition. This prevailed for a few hours and then rapidly recovered. In addition, shifts in bacterial community structure following exposure to oil were determined by denaturing gradient gel electrophoresis of PCR-amplified fractions of 16S rRNA from eubacteria, cyanobacteria and sulfate-reducing bacteria. Since the mats used for the present study were obtained from oil-contaminated environments, they were believed to be preequilibrated for petroleum remediation. The mesocosm system at Eilat provided a unique opportunity to study petroleum degradation by mats formed under different salinities (up to 21%). These mats, dominated by cyanobacteria, can serve as close analogues to the sabkhas contaminated during the Gulf War in Kuwait and Saudi Arabia (AU)

En la costa africana del canal de Suez y en el Lago Solar de la península del Sinaí, se recogieron muestras de tapetes de cianobacterias que crecen en «sabkhas» contaminadas por petróleo, para su posterior estudio. Dichas muestras degradaron de manera efectiva el petróleo en un ambiente iluminado; tras la degradación se produjo un crecimiento intenso de Phormidium spp. y Oscillatoria spp. Sin embargo, las cepas aisladas no degradan el petróleo en cultivos axénicos. Las cepas de bacterias sulfatorreductoras, así como los heterótrofos aeróbicos degradaban compuestos de hidrocarburos alifáticos y aromáticos. Los resultados indican que la degradación del petróleo se debía principalmente a la acción de las bacterias heterótrofas aeróbicas. La fotosíntesis oxigénica de cianobacterias no sensibles al petróleo proporcionaba el oxígeno molecular para el metabolismo aeróbico de organismos como Marinobacter sp. Los cambios diurnos de las condiciones ambientales en la superficie del tapete, desde altas concentraciones de oxígeno durante la fase iluminada a altas concentraciones de sulfuro y anaerobiosis en la oscuridad, permiten la degradación combinada aeróbica y anaeróbica de crudo de petróleo en la superficie del tapete. Así pues, los tapetes de cianobacterias que se desarrollan en la costa pueden utilizarse para la degradación de los vertidos de petróleo que afectan la costa. Mediante electrodos de oxígeno se detectó una inhibición significativa de la actividad fotosintética posterior al añadido de petróleo Dicha inhibición se prolongó durante algunas horas y luego se recuperó rápidamente. Además, el análisis mediante electroforesis de gel en gradiente desnaturalizante (DGGE) de las fracciones de RNA 16S de eubacterias, cianobacterias y bacterias sulfatorreductoras amplificadas mediante PCR, reveló un cambio estructural en las comunidades bacterianas. Puesto que los tapetes usados para el estudio fueron obtenidos en ambientes contaminados por petróleo, se cree que dichos tapetes están preequilibrados para la biorremediación del petróleo. El sistema de mesocosmos en Eilat ha proporcionado una oportunidad única para estudiar la degradación del petróleo mediante tapetes formados a distintas salinidades (de hasta el 21 por ciento). Estos tapetes, en los que predominan las cianobacterias, sirven como análogos a las “sabkhas” contaminadas durante la Guerra del Golfo en Kuwait y en Arabia Saudí. (AU)

Potential of Burkholderia capacia RQ1 in the biodegradation of heavy crude oil

The potential of Burkholderia cepacia strain RQ1 in the biodegradation of heavy crude oil (Maya) was assessed to develop an active indigenous bacterial consortium for the bioremediation of crude oil-polluted systems in Nigeria. The heavy crude oil (Maya) was utilized as sole source of carbon, attaining maximum cell densities of 10(8) cfu ml(-1) from an initial 10(5) cfu ml(-1) in 15 days. Biomass also increased with oil concentrations up to 0.8% (w/v). Growth rates ranged from 0.028 h(-1) to 0.036 h(-1) and degradation rates decreased with increasing concentrations of oil from 0.009 day(-1) to 0.004 day(-1). The quantity of oil metabolized increased significantly (P < 0.05) with increasing concentrations of oil. However, the growth of the bacterium was inhibited at crude oil concentrations beyond 6% (w/v). The pH of the culture media also dropped significantly (P < 0.05) during the 15-day test period, while the non-asphaltic fractions of the oil were significantly reduced (by about 89%) during the same period. The bacterium harbours a plasmid of about 10 kb that lacks restriction sites for the endonucleases Asp718, BamHI and PstI (AU)

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