Acute and subchronic effects of petroleum on the freshwater fish Hoplias aff. malabaricus / Efeitos agudo e subcrônico do petróleo no peixe de água doce Hoplias aff. malabaricus

Abstract Petroleum water soluble fraction (WSF) impairs organisms, but damages may vary among cell and tissue levels. The aim of the present study was to evaluate the acute (24 h, 48 h, 72 h) and subchronic effects (36 days) of WSF (0%, 25% and 100%) in juveniles of the Neotropical top predator fish Hoplias aff. malabaricus. The effects of WSF were evaluated at a molecular level using the comet assay and micronucleus test for genome damage; and at a morphological level through histological identification of liver pathologic lesions. In both acute and subchronic exposure we found low levels of DNA damage (< 10% of comet tail) and non-significant frequency of micronucleus in WSF exposed fish. The most significant liver lesions in WSF exposed fish were fatty vacuolization, hypertrophy and focal necrosis. Since these tissue injuries were progressive and persistent, their irreversibility may negatively affect fish recruitment, even in a such resistant top predator.

Resumo A fração solúvel de petróleo (WSF) prejudica os organismos, porém os danos podem variar entre os níveis celular e tecidual. O objetivo do presente estudo foi avaliar o efeito agudo (24 h, 48 h e 72 h) e subcrônico (36 dias) da WSF (0%, 25% e 100%) em juvenis do peixe neotropical predador topo Hoplias aff. malabaricus. Os efeitos da WSF foram avaliados no nível molecular utilizando o ensaio do cometa e o teste do micronúcleo para o dano genômico e no nível morfológico através da identificação histológica de lesões patológicas no fígado. Em ambas exposições (aguda e subcrônica) encontramos baixos níveis de dano no DNA (< 10% de DNA na cauda do cometa) e frequência de micronúcleos não significativa em peixes expostos a WSF. As lesões mais significativas no fígado dos peixes expostos a WSF foram a vacuolização lipídica, hipertrofia e focos de necroses. Como estas lesões foram progressivas e persistentes, sua irreversibilidade pode afetar negativamente o recrutamento dos peixes, mesmo sendo um predador topo resistente.

The degradation of plastics and the production of polyhydroxyalkanoates (PHA) / 生物工程学报

In recent years, the petroleum-based plastic pollution problem has been causing global attention. The idea of "degradation and up-cycling of plastics" was proposed for solving the environmental pollution caused by non-degradable plastics. Following this idea, plastics would be firstly degraded and then reconstructed. Polyhydroxyalkanoates (PHA) can be produced from the degraded plastic monomers as a choice to recycle among various plastics. PHA, a family of biopolyesters synthesized by many microbes, have attracted great interest in industrial, agricultural and medical sectors due to its biodegradability, biocompatibility, thermoplasticity and carbon neutrality. Moreover, the regulations on PHA monomer compositions, processing technology, and modification methods may further improve the material properties, making PHA a promising alternative to traditional plastics. Furthermore, the application of the "next-generation industrial biotechnology (NGIB)" utilizing extremophiles for PHA production is expected to enhance the PHA market competitiveness, promoting this environmentally friendly bio-based material to partially replace petroleum-based products, and achieve sustainable development with carbon-neutrality. This review summarizes the basic material properties, plastic upcycling via PHA biosynthesis, processing and modification methods of PHA, and biosynthesis of novel PHA.

Biodegradation of polyethylene terephthalate: a review / 生物工程学报

Plastics are widely used in human daily life, which bring great convenience. Nevertheless, the disposal of a large amount of plastic wastes also brings great pressure to the environment. Polyethylene terephthalate (PET) is a polymer thermoplastic material produced from petroleum. It has become one of the most commonly used plastics in the world due to its durability, high transparency, light weight and other characteristics. PET can exist in nature for a long time due to its complex structure and the difficulty in degradation, which causes serious pollution to the global ecological environment, and threatens human health. The degradation of PET wastes has since become one of the global challenges. Compared with physical and chemical methods, biodegradation is the greenest way for treating PET wastes. This review summarizes the recent advances on PET biodegradation including microbial and enzymatic degradation of PET, biodegradation pathway, biodegradation mechanisms, and molecular modification of PET-degrading enzymes. In addition, the prospect for achieveing efficient degradation of PET, searching and improving microorganisms or enzymes that can degrade PET of high crystallinity are presented, with the aimto facilitate the development, application and molecular modification of PET biodegradation microorganisms or enzymes.

Effect of occupational exposure on hematological and biochemical parameters in workers at oil and gas companies

Petroleum refineries are largest chemical industries that are responsible for emission of several pollutants into the atmosphere. Benzene and its metabolites are regarded as the most hazardous compounds that are emitted by petroleum refineries. These contribute to toxic oxidants, which cause many serious health risks to petroleum refineries workers. This study was aimed to analyze the effects of chemical exposure on hematological and biochemical parameters among workers at Zawia oil refinery and Mellituh oil and gas refinery companies. A total of 200 workers participated in this study which consisting of two equal groups (each group: n = 100). The first group consists of petroleum refineries workers and the second group consists of non-oil work civil servants serving were recruited as exposed and control subjects, respectively. The results of blood picture, liver enzymes and kidney functions were compared between the groups. Mean white blood cells counts, platelet counts, and hematocrit count were significantly higher, while the mean red blood cells count was insignificantly changed in petroleum refineries workers. While the mean hemoglobin and corpuscular hemoglobin concentration levels were significantly lower, whereas the mean corpuscular volume and mean corpuscular hemoglobin levels were insignificantly changed in petrol refineries workers. Liver enzymes and renal functions were significantly higher in petrol refineries workers. The present findings indicate that occupational exposure to benzene causes significant alterations in hematological and biochemical parameters and workers are at high risk of developing blood, hepatic or renal related disorders. Protection and frequent medical attention should be given to petroleum refineries workers.

Analysis of lung cancer screening through low-dose spiral computed tomography among petroleum company staffs in Sichuan-Chongqing Area in 2020 / 中华劳动卫生职业病杂志

Objective: To provide scientific evidence for early lung cancer screening, to analyze the incidence of pulmonary nodules among petroleum company staffs in Sichuan-Chongqing Area. Methods: In January 2021 , 6002 petroleum company staffs in Sichuan-Chongqing Area which scanned by low-dose spiral computed tomography (LDCT) of chest in medical examination center in 2020 were retrospectively collected as objects. Their imaging and clinical data were collected. χ(2) test was used to analyze the differences in the detection rates of lung nodules and suspected lung cancer nodules among workers in petroleum company staffs of different genders, ages and types of work. Results: Among the 6002 objects, 3853 (64.2%) were male and 2149 (35.8%) were female, with an average age of (47.25±12.13) years old. A total of 431 cases (7.2%) of pulmonary nodules and 57 cases (0.9%) of suspected lung cancer nodules were detected. 45 cases were followed up with surgical treatment, and 41 cases (91.1%) of lung cancer were diagnosed by postoperative pathology. There were significant differences in the detection rates of pulmonary nodules and suspected lung cancer nodules between different age groups (χ(2)=51.23, 18.81 , P<0.001). The detection rates of pulmonary nodules in the age groups 51-60 years old and ≥61 years old were higher than those in the age groups≤40 years old and 41-50 years old (P<0.05). The detection rate of suspected lung cancer nodules in the age group≥ 61 years old was higher than those in the age groups≤40 years old, 41-50 years old and 51-60 years old (P< 0.05) . And the detection rate of suspected lung cancer pulmonary nodules in oil workers was higher than that of ordinary workers (P<0.05) . Among female objects, the detection rate of pulmonary nodules in oil workers was higher than that in ordinary workers (χ(2)=8.09, P=0.004) . The detection rate of pulmonary nodules in oil workers aged ≥61 years old was higher than ordinary workers (χ(2)=37.94, P<0.001) . Among male objects, the detection rate of suspected lung cancer pulmonary nodules in oil workers was higher than that in ordinary workers (χ(2)=8.42, P=0.004) . The detection rates of suspected lung cancer pulmonary nodules in oil workers aged 51-60 years old and ≥61 years old groups were higher than those of ordinary workers (χ(2)=4.70, 8.74; P=0.030, 0.003) . Conclusion: LDCT is suitable for early lung cancer screening for petroleum company staffs. During the clinical screening process, LDCT should be used as a routine physical examination item for petroleum workers older than 51 years old.

Biodegradation of petroleum by bacteria isolated from fishes of Indian Ocean / Biodegradação do petróleo por bactérias isoladas de peixes do oceano Índico

In this study, oil degrading bacteria discovered from fish living near the oil ports at Karachi in Pakistan were characterized. The bacteria isolated from skin, gills, and gut in fish could consume crude oil as a source of carbon and energy. Total 36 isolates were tested using Nutrient Agar (NA) and MSA media with different crude oil concentrations (0.2%, 0.5%, 0.7%, 1%, 2%, and 5%) and 4 out of 36 isolates (two Gram positive and two Gram negative bacteria) were selected for further identification. 16S rRNA gene sequencing revealed that the isolates are related to Bacillus velezensis, Bacillus flexus, Pseudomonas brenneri and Pseudomonas azotoforman. Oil degrading potential of these bacteria was characterized by GC-MS analysis of degradation of oil components in crude oil as well as engine oil. We found that one (2, 6, 10, 14-Tetramethylpentadecane) out of 42 components in the crude oil was fully eliminated and the other oil components were reduced. In addition, 26 out of 42 oil components in the engine oil, were fully eliminated and the rest were amended. Taken together, these studies identify that B. velezensis, B. flexus, P. brenneri and P. azotoforman have high oil degrading potential, which may be useful for degradation of oil pollutants and other commercial applications.

Neste estudo, bactérias degradadoras de óleo descobertas em peixes que vivem perto dos portos de petróleo em Karachi, no Paquistão, foram caracterizadas. As bactérias isoladas da pele, guelras e intestinos dos peixes podem consumir petróleo bruto como fonte de carbono e energia. No total, 36 isolados foram testados usando Agar Nutriente (NA) e meio MSA com diferentes concentrações de óleo bruto (0,2%, 0,5%, 0,7%, 1%, 2% e 5%) e 4 de 36 isolados (dois Gram positivos e duas bactérias Gram negativas) foram selecionadas para posterior identificação. O sequenciamento do gene 16S rRNA revelou que os isolados estão relacionados a Bacillus velezensis, Bacillus flexus, Pseudomonas brenneri e Pseudomonas azotoforman. O potencial de degradação do óleo dessas bactérias foi caracterizado pela análise de GC-MS da degradação dos componentes do óleo no óleo cru, bem como no óleo do motor. Descobrimos que um (2, 6, 10, 14-tetrametilpentadecano) de 42 componentes do óleo cru foi totalmente eliminado e os outros componentes do óleo foram reduzidos. Além disso, 26 dos 42 componentes do óleo do motor foram totalmente eliminados e o restante corrigido. Juntos, esses estudos identificam que B. velezensis, B. flexus, P. brenneri e P. azotoforman têm alto potencial de degradação de óleo, o que pode ser útil para a degradação de poluentes de óleo e outras aplicações comerciais.

Effect of Petroleum Ether Extract of Rhizoma Amorphophalli on Biological Characteristics of K562 Cells and Its Mechanism / 中国实验血液学杂志

OBJECTIVE@#To investigate the role of petroleum ether extract of Rhizoma Amorphophalli (SLG) in inhibiting proliferation and promoting apoptosis and differentiation of leukemia K562 cells.@*METHODS@#K562 cells were processed by SLG and PD98059 which was the ERK signaling pathway blocker. Then cell vitality was tested by MTT. Cell apoptosis rate and positive percentage of antigen expression related with differentiation were detected by flow cytometry. The protein expression levels of ERK1/2 and pERK1/2 were detected by Western blot.@*RESULTS@#The proliferation activity of K562 was reduced by 50, 100, 200 mg/L SLG in a concentration dependent manner (r=0.9997). The apoptosis rate and positive expression rate of CD11b, CD14 and CD42b which were related with differentiation were raised by SLG, as well as the expression of pERK1/2, while PD98059 could reverse the promoting effect of SLG on apoptosis and differentiation partially.@*CONCLUSION@#SLG can inhibit the proliferation and promote apoptosis and differentiation of K562 cells through ERK signaling pathway.

Advances in biodegradation of petroleum hydrocarbons / 生物工程学报

Petroleum hydrocarbon pollutants are difficult to be degraded, and bioremediation has received increasing attention for remediating the hydrocarbon polluted area. This review started by introducing the interphase adaptation and transport process of hydrocarbon by microbes. Subsequently, the advances made in the identification of hydrocarbon-degrading strains and genes as well as elucidation of metabolic pathways and underpinning mechanisms in the biodegradation of typical petroleum hydrocarbon pollutants were summarized. The capability of wild-type hydrocarbon degrading bacteria can be enhanced through genetic engineering and metabolic engineering. With the rapid development of synthetic biology, the bioremediation of hydrocarbon polluted area can be further improved by engineering the metabolic pathways of hydrocarbon-degrading microbes, or through design and construction of synthetic microbial consortia.

Advances in bioremediation of hydrocarbon-contaminated soil / 生物工程学报

With continuous improvement of people's living standards, great efforts have been paid to environmental protection. Among those environmental issues, soil contamination by petroleum hydrocarbons has received widespread concerns due to the persistence and the degradation difficulty of the pollutants. Among the various remediation technologies, in-situ microbial remediation enhancement technologies have become the current hotspot because of its low cost, environmental friendliness, and in-situ availability. This review summarizes several in-situ microbial remediation technologies such as bioaugmentation, biostimulation, and integrated remediation, as well as their engineering applications, providing references for the selection of in-situ bioremediation technologies in engineering applications. Moreover, this review discusses future research directions in this area.

Advances in the bioaugmentation-assisted remediation of petroleum contaminated soil / 生物工程学报

Bioremediation is considered as a cost-effective, efficient and free-of-secondary-pollution technology for petroleum pollution remediation. Due to the limitation of soil environmental conditions and the nature of petroleum pollutants, the insufficient number and the low growth rate of indigenous petroleum-degrading microorganisms in soil lead to long remediation cycle and poor remediation efficiency. Bioaugmentation can effectively improve the biodegradation efficiency. By supplying functional microbes or microbial consortia, immobilized microbes, surfactants and growth substrates, the remediation effect of indigenous microorganisms on petroleum pollutants in soil can be boosted. This article summarizes the reported petroleum-degrading microbes and the main factors influencing microbial remediation of petroleum contaminated soil. Moreover, this article discusses a variety of effective strategies to enhance the bioremediation efficiency, as well as future directions of bioaugmentation strategies.

Degradation of petroleum-based plastics by microbes and microbial consortia / 生物工程学报

Along with the increasingly serious environmental pollution, dealing with the "white pollution" issue, which is caused by the worldwide use of not readily-degradable or non-degradable synthetic plastics, has become a great challenge. It is an environmentally friendly strategy to degrade synthetic plastics using microorganisms that exist in nature or evolved under selection pressure. Based on the NSFC-EU International Cooperation and Exchanges Project "Bio Innovation of a Circular Economy for Plastics", this review summarized the screening of bacteria, fungi and microbial consortia capable of degrading synthetic plastics such as polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyurethane (PUR), and polyethylene terephthalate (PET). We also analyzed the role of various microorganisms played in the degradation of petroleum-based plastics. Moreover, we discussed the pros and cons of using microorganisms and enzymes for degradation of synthetic plastics.

Engineering progress in microbial production of polyhydroxyalkanoates / 生物工程学报

Polyhydroxyalkanoates (PHAs) are polymers obtained by esterification of hydroxy fatty acid monomers. Due to similar mechanical characteristics of traditional petroleum-based plastics, 100% biodegradability and biocompatibility, PHAs are considered to be one of the most potential green materials. However, the application and promotion of PHAs as a green and environmentally friendly material are difficult because of the high production costs. This article focuses on the current methods to reduce production cost of PHAs effectively, such as cell morphology regulation, metabolic pathway construction, economic carbon source utilization and open fermentation technology development. Despite most research results are still limited in laboratory, the research methods and directions provide theoretical guidance for the industrial production of economic PHAs.

Isolation and characterization of hydrocarbon-degrading bacteria from gas station leaking-contaminated groundwater in the Southern Amazon, Brazil / Isolamento e caracterização de bactérias degradadoras de hidrocarbonetos de água subterrânea contaminada por vazamentos em posto de combustível no sul da Amazônia, Brasil

Abstract Twenty-three hydrocarbon-degrading bacteria strains were isolated from gas station leaking-contaminated groundwater located in the Southern Amazon, Brazil. Based on hydrocarbon (diesel, hexadecane, benzene, toluene and xylene) degradation ability, two strains were selected for further study. The amplification and sequencing of the 16S rRNA gene showed that these two strains belonged to the genus Bacillus (Bacillus sp. L26 and Bacillus sp. L30). GC-MS analysis showed that strain L30 was the most effective in degrading n-alkane (C10-C27) from diesel after 7 days of cultivation in mineral medium. Both strains produced biosurfactants and showed emulsification activity, specially the strain L30. Alkane hydroxylase gene (group III), which is important for alkane biodegradation, was present in strains. As a result, this study indicated that these bacteria could have promising applications in hydrocarbon bioremediation.

Resumo Vinte e três linhagens bacterianas degradadoras de hidrocarbonetos foram isoladas de água subterrânea contaminada por vazamento em posto de combustível no sul da Amazônia, Brasil. Com base na habilidade de degradar hidrocarbonetos (diesel, hexadecano, benzeno, tolueno e xileno), duas linhagens foram selecionadas para estudos posteriores. A amplificação e sequenciamento do gene 16S rRNA demonstrou que essas linhagens pertencem ao gênero Bacillus (Bacillus sp. L26 and Bacillus sp. L30). Análises de GC-MS mostraram que a linhagem L30 foi mais eficiente em degradar n-alcanos (C10-C27) presentes no diesel, após 7 dias de cultivo em meio mineral. Ambas as linhagens produziram biossurfactantes e apresentaram atividade emulsificante, especialmente a linhagem L30. O gene alcano hidroxilase (grupo III), o qual é importante para degradação de alcanos, foram detectados nas linhagens. Como resultado, este estudo indicou que essas linhagens bacterianas podem ser promissoras se aplicadas em processos de biorremediação.

Aspectos de regulação internacional do petróleo: o caso Brasil / Aspects of international oil regulation: the Brazil case

O presente trabalho tem por objeto abordar os aspectos de regulação internacional do petróleo, mais precisamente aqueles previstos na Convenção das Nações Unidas sobre o direito do mar de 1982, que definem a obrigatoriedade do pagamento de royalties às Nações Unidas advindos da exploração dos hidrocarbonetos nas plataformas estendidas. Utiliza o método dedutivo e o tipo de pesquisa exploratório e comparativo, o artigo dividiu-se em três capítulos. Após introduzir o leitor ao tema, abordando-se as particularidades do direito do mar e seu viés de exploração econômica, os autores discorrem sobre a questão com uma dimensão da regulação quase sempre ausente da formulação de políticas energéticas. Essa discussão é apresentada a partir do estudo de caso do Brasil. Para tanto, cuida de apresentar a importância do setor petrolífero e o histórico da exploração offshore no Brasil. Adentra-se em seguida a temática da distribuição dos royalties entre o estado nacional e as nações unidas. No desenvolvimento da questão são trazidos à tona o possíveis cenários entre o futuro da exploração petrolífera no Brasil e os resultados da aplicação da regulação internacional pela Convenção das Nações Unidas sobre o Direito do Mar de 1982. Por fim, chegou-se à conclusão de que algumas plataformas de petróleo já estão localizadas próximas do limite das 200 milhas marítimas e o polígono do pré-sal também encontra-se adentrando as 200 milhas marítimas, o que demonstra uma necessidade de uma abordagem imparcial sobre os prós e contras do posicionamento brasileiro, analisando os possíveis cenários futuros.

This papers seeks to verify aspects of the international regulation of oil, specifically those contained in the 1982 United Nations Convention on the Law of the Sea that refer to the obligation to pay royalties to the United Nations on the exploration by the Brazilian government of hydrocarbons in extended platforms. The deductive method and exploratory and comparative research were used. After identifying how the work was carried out, it discusses the issue of law of the sea and the economic exploitation discourses on the theme, their motivation and the context of work to be investigated. The authors also discuss the issue within the dimension of regulation being almost always absent from the formulation of energy policies. The discussion is grounded on a case study of Brazil and presents the importance of the oil industry, the history of offshore exploration in Brazil, and even the distribution of royalties between the national state and the United Nations. In the development of this issue, possible scenarios are brought to light regarding the future of offshore oil exploration in Brazil and the results of enforcement of international regulation by the 1982 United Nations Convention on the Law of the Sea. Finally, we reach the conclusion that some oil rigs are already located near the 200 nautical miles limit and that the polygon of the pre-salt oils reserves is also entering this limit, demonstrating the need for an impartial reckoning of the pros and cons of Brazil's position by analyzing possible future scenarios.

Petroleum contamination and bioaugmentation in bacterial rhizosphere communities from Avicennia schaueriana

ABSTRACT Anthropogenic activity, such as accidental oil spills, are typical sources of urban mangrove pollution that may affect mangrove bacterial communities as well as their mobile genetic elements. To evaluate remediation strategies, we followed over the time the effects of a petroleum hydrocarbon degrading consortium inoculated on mangrove tree Avicennia schaueriana against artificial petroleum contamination in a phytoremediation greenhouse experiment. Interestingly, despite plant protection due to the inoculation, denaturing gradient gel electrophoresis of the bacterial 16S rRNA gene fragments amplified from the total community DNA indicated that the different treatments did not significantly affect the bacterial community composition. However, while the bacterial community was rather stable, pronounced shifts were observed in the abundance of bacteria carrying plasmids. A PCR-Southern blot hybridization analysis indicated an increase in the abundance of IncP-9 catabolic plasmids. Denaturing gradient gel electrophoresis of naphthalene dioxygenase (ndo) genes amplified from cDNA (RNA) indicated the dominance of a specific ndo gene in the inoculated petroleum amendment treatment. The petroleum hydrocarbon degrading consortium characterization indicated the prevalence of bacteria assigned to Pseudomonas spp., Comamonas spp. and Ochrobactrum spp. IncP-9 plasmids were detected for the first time in Comamonas sp. and Ochrobactrum spp., which is a novelty of this study.

Evaluación in vitro de la capacidad biorremediadora de hongos filamentosos sobre petróleo crudo / Bioremediative Capacity Evaluation in vitro of the filamentous fungi on crude oil

Resumen Objetivo. Evaluar la capacidad biorremediadora de algunas especies de hongos filamentosos en suelos contaminados con petróleo crudo. Métodos. Se aislaron 138 cepas a partir de 90 cultivos primarios en muestras de suelos obtenidas en los municipios de Yondó (Antioquia), Acacías (Meta) y Tumaco (Nariño), se identificaron las especies por medio de claves taxonómicas y la amplificación por PCR de la región ITS ubicándose en siete géneros de hongos filamentosos. Del total de las especies se escogieron tres para el experimento que fueron: Neosartorya sp. Cepa A/N -1, Aspergillus sp. Cepa Y/As-3 y Rhizomucor sp. Cepa 1A/R-1; se realizó la micorremediación con la técnica de Landfarming modificado al diseñarse un microcosmos con 50g de suelo contaminado con petróleo crudo °API de 21.6 a concentraciones de 20.000 ppm y 30.000ppm para cada una de las especies en un inóculo de 300 conidios/ml en agua destilada, ajustado en cámara de Neubauer y las tres especies en consorcio en suelo contaminado con petróleo crudo °API de 21.6 a concentraciones de 40.000ppm, 60.000ppm, 80.000ppm y 100.000ppm con un inóculo de 300 conidios/ml. Se valoró el proceso por espectofotometría. Además se estableció las enzimas empleadas en la micorremediación y la citotoxicidad de las cepas empleadas. Resultado. La micorremediación realizada por las especies individuales fue en promedio entre 2 y 6 días y cuando se aplicaron las tres especies en consorcio se realizó en un promedio entre 6 y 10 días, la enzima empleada es peroxidasa y la citotoxicidad es negativa.

Abstract Objective. Evaluate the bioremediation capacity of some species of filamentous fungi in soils contaminated with crude oil. Methods. 138 strains were isolated from 90 primary culture in soil samples obtained in the municipalities of Yondó (Antioquia), Acacías (Meta) and Tumaco (Nariño), species were identified by means of taxonomic keys and PCR amplification of the ITS region located in seven genera of filamentous fungi. Of the total of the species, three were chosen for the experiment, which were: Neosartorya sp. Cepa A/N- 1, Aspergillus sp. Cepa Y/As -3 and Rhizomucor sp. Cepa 1A/R-1; Micoremediation was performed with the modified Landfarming technique when designing a microcosm with 50g of soil contaminated with crude oil API 21.6 at concentrations of 20,000 ppm and 30,000ppm for each of the species in an inoculum of 300 conidia / ml in water distilled, adjusted in Neubauer chamber and the three species in consortium in soil contaminated with crude oil API 21.6 at concentrations of 40,000ppm, 60,000ppm, 80,000ppm and 100,000ppm with an inoculum of 300 conidia / ml. The process was evaluated by spectrophotometry. In addition, the enzymes used in the micoremediation and cytotoxicity of the strains used were established. Result. The micoremediation performed by the individual species was on average between 2 and 6 days and when the three species were applied in a consortium it was carried out on average between 6 and 10 days, the enzyme used is peroxidase and the cytotoxicity is negative.

Indagación exploratoria in vitro de la capacidad degradadora de la cepa comercial Pleurotus ostreatus sobre dos concentraciones de petróleo crudo / In vitro inquiry on two concentrations of crude oil degradation ability by a commercial strain of Pleurotus ostreatus

Resumen Objetivo. Evaluar la potencial actividad degradadora de la cepa comercial Pleurotus ostreatus sobre petróleo crudo como única fuente de carbono. Método. Se empleó un inóculo de 10mg del hongo en medio mínimo líquido de sales con volúmenes de 0,5% y 1% de petróleo en agitación constante durante 21 días a temperatura ambiente, registrando peso seco a los 0, 8,15 y 21 días. Resultados. Se obtuvo un máximo de biomasa 45mg para 0,5% de 39mg para 1%. Esto sugiere que el hongo sufre una adaptación fisiológica para utilizar el petróleo crudo para su crecimiento.

Abstract Objectives. To evaluate the potential crude oil-degrading activity of Pleurotus ostreatus using it as the sole source of carbon and energy for growth. Methods. An inoculum of 10 mg of the fungus in the minimal liquid of salt with 0.5% or 1% crude oil in constant agitation for 21 days was used. Dry weight at 0, 8, 15 and 21 days was obtained. Results. The maximum biomass with a value of 45mg of 0.5% oil treatment registered while the 1% oil treatment reached a value of 39mg. These values suggest physiological adaptation of the fungus to crude oil as its sole carbon source for growth.

The effects of oil pollution in the development of Ejidal Communities: the case of the San Juan river basin (Nuevo León, Mexico) / Los efectos de la contaminación petrolera en el desarrollo de comunidades ejidales: el caso de la cuenca del río san juan (nuevo león, méxico)

RESUMEN La presente investigación analiza, en varios ejidos, los efectos sociales, económicos y ecológicos causados por el derrame de petróleo en el río San Juan (Nuevo León, México). Con este fin, se realizaron encuestas entre los pobladores y entrevistas a actores clave. Los resultados de la investigación indican que, sobre todo, la problemática social causada por el desastre es poco valorada y atendida por el perpetrador y descuidada por el Estado. Lo anterior muestra la inconciencia o la corrupción del Gobierno para internalizar los costos sociales que ocasiona la producción de un producto que en su momento fue monopolio del Estado y, por tanto, debía beneficiar al conjunto de la población.

ABSTRACT The present investigation analyzes, in several ejidos, the social, economic and ecological effects caused by the oil spill in the San Juan River (Nuevo León, Mexico). To this end, surveys were conducted among the settlers and interviews with key actors. The results of the investigation indicate that, above all, the social problems caused by the disaster are little valued and taken care of by the perpetrator and neglected by the State. The shows the unconsciousness or corruption of the Government to internalize the social costs caused by the production of a product that at the time was a monopoly of the State and, therefore, should benefit the entire population.

Reintroducing plant coverage in a tropical wetland contaminated with oil and sulfate: rhizosphere effects on Desulfovibrio populations / Reintroducción de cobertura vegetal en un humedal tropical contaminado con petróleo y sulfato: efecto de la rizosfera sobre poblaciones de Desulfovibrio

Abstract The Mexican tropical wetland is a coastal system with capacity to support the contamination derived from the extractive industry and the transformation of crude oil, due to its high plant biodiversity and the presence of rhizospheric reducing sulphate bacteria from plants tolerant to crude oil. A field experiment was carried out for nine months to evaluate the adaptation of aquatic plants Leersia hexandra grass and Eleocharis palustris spikerush reintroduced in a wetland contaminated with 75 560 to 118 789 mg kg-1 of weathered petroleum and also with sulfate, derived from oil and gas pipeline leaks, and gaseous emissions. The effect of the weathered oil and sulfate on the dry matter production and the population density of the bacterium Desulfovibrio spp, isolated from the rhizosphere and soil of both plants, were evaluated. The means of the variables had statistical differences (p< 0.05). Weathered oil inhibited dry matter production of L. hexandra but not E. palustris; the effect of petroleum on Desulfovibrio density was very significant negative in the rhizosphere and in the soil of both plants. Sulfate reduced the dry matter of grass. The exposure of Desulfovibrio to sulfate significantly reduced its density in rhizosphere and soil (p< 0.01). We recommend the use of E. palustris for the decontamination of flooded soils contaminated with weathered oil and sulfate. Rev. Biol. Trop. 66(2): 908-917. Epub 2018 June 01.

Resumen El humedal tropical mexicano es un sistema costero con capacidad para resistir la contaminación derivada de la industria extractiva y la transformación del petróleo crudo, debido a su alta biodiversidad de plantas y la presencia de bacterias rizosféricas reductoras de sulfato de plantas tolerantes al petróleo crudo. Se realizó un experimento en campo durante nueve meses para evaluar la adaptación de las plantas acuáticas Leersia hexandra y Eleocharis palustris reintroducidas en un humedal contaminado con 75 560 a 118 789 mg kg-1 de petróleo intemperizado y también con sulfato, derivados de fugas de oleoductos y de emisiones gaseosas crónicas. Se evaluó el efecto del petróleo intemperizado y del sulfato en la producción de materia seca vegetal y en la densidad poblacional de la bacteria Desulfovibrio spp, aislada de la rizosfera y del rizoplano de ambas especies vegetales. Las medias de las variables tuvieron diferencias estadísticas (p< 0.05). El petróleo intemperizado inhibió la producción de materia seca de L. hexandra pero no de E. palustris; el efecto del petróleo en la densidad de Desulfovibrio fue negativo muy significativo en la rizosfera y en el rizoplano de ambas plantas. El sulfato redujo la materia seca de L. hexandra. La exposición de Desulfovibrio a sulfato redujo muy significativamente (p< 0.01) su densidad en rizosfera y en rizoplano. Recomendamos el uso de E. palustris para la descontaminación de suelos inundables afectados con petróleo intemperizado y con sulfato.

Temporal assessment of microbial communities in soils of two contrasting mangroves

ABSTRACT Variations in microbial communities promoted by alterations in environmental conditions are reflected in similarities/differences both at taxonomic and functional levels. Here we used a natural gradient within mangroves from seashore to upland, to contrast the natural variability in bacteria, cyanobacteria and diazotroph assemblages in a pristine area compared to an oil polluted area along a timespan of three years, based on ARISA (bacteria and cyanobacteria) and nifH T-RFLP (diazotrophs) fingerprinting. The data presented herein indicated that changes in all the communities evaluated were mainly driven by the temporal effect in the contaminated area, while local effects were dominant on the pristine mangrove. A positive correlation of community structure between diazotrophs and cyanobacteria was observed, suggesting the functional importance of this phylum as nitrogen fixers in mangroves soils. Different ecological patterns explained the microbial behavior in the pristine and polluted mangroves. Stochastic models in the pristine mangrove indicate that there is not a specific environmental factor that determines the bacterial distribution, while cyanobacteria and diazotrophs better fitted in deterministic model in the same area. For the contaminated mangrove site, deterministic models better represented the variations in the communities, suggesting that the presence of oil might change the microbial ecological structures over time. Mangroves represent a unique environment threatened by global change, and this study contributed to the knowledge of the microbial distribution in such areas and its response on persistent contamination historic events.