Effects Of Petroleum Hydrocarbons Research Articles

Effects of pollution of saline soils with oil and oil products on soil physical properties

In the article, pollution of saline soils with oil and oil products, physical and water-physical properties depending on the level of salinity are studied. As a result of the research, it is scientifically based that the increase in the level of contamination of the soil is subject to the decrease in water permeability, and the decrease in the level of pollution is subject to the law of the increase in water permeability. In the article, weakly, moderately, strongly and very strongly contaminated soils with oil were studied. According to the results, it was determined that the water permeability of the soil was observed in 25, 45, 45, 37, 5, 3, 2 minutes, and it carried 75, 26, 44, 45, 540, 1050, 1200 ml of water, respectively, for 90 minutes. The amount of water transfer compared to the control soil for 90 minutes was less in 1%, 2%, 5% contaminated soils, and very high in 15%, 25% and 37.5% contaminated soils. The increase in the level of pollution is explained by the deterioration of water permeability and moisture retention. Also, due to the fact that oil is a viscous organic pollutant, the changes of 0.25, 0.5, 1, 3, 5, 7, 10 mm microaggregates, which are important for soil fertility, as a result of pollution, and changes in the amount of these microaggregates were also determined. It was found that the soils around the South Mirshodi oil field were previously contaminated and the amount of microaggregates smaller than 0.25 mm, 0.25 mm, 1 mm, 2 mm and 3 mm in the irrigated soils increased as the distance from the source of contamination increased. This is explained by the decrease in the concentration of oil in the soil. The amount of 5 mm, 7 mm and 10 mm aggregates has decreased. A similar situation was observed around the Kumkurgan oil base. The effect of petroleum hydrocarbons is more noticeable in microaggregates with a diameter of 10 mm.

BIOREMEDIATION OF CONTAMINATED SOIL WITH PETROLEUM PRODUCTS

Petroleum products are recognized as one of the most environmentally hazardous soil contaminants. The sources of this pollution are the enterprises of petroleum and chemical industry, transport, landfills. Soil has the ability to absorb many chemicals and retain them in the surface, fertile layer. Petroleum products change the mechanical, chemical, biochemical and physico-chemical characteristics of the soil, which can lead to the destruction of plants and microorganisms and affects on the soil self-cleaning. The degree of petroleum products impact on plants and microorganisms depends on many factors: temperature and humidity of the air and soil, the amount of nutrients, soil type, the concentration of pollutants. The effect of petroleum products on plants is due direct toxic effects and transformation of the soil environment. At the cellular and physiological level, the effect of petroleum hydrocarbons on plants is appeared in the violation of the structure of chloroplasts and photosynthesis. Hydrocarbons damage the membranes of chloroplasts, mitochondria, root cell membranes. Plants that grow in conditions of petroleum pollution of the soil contain more substances with stress-protective properties. The impact of soil contamination on plants can be direct and indirect. Direct impact - is the impact of petroleum components on plants, indirect impact - are changes in morphological, physicochemical and biological properties of the soil. Moreover, petroleum pollution can have negative and stimulating effects on plants. Therefore, determination the phytotoxic effect in soils contaminated with petroleum products, for selection the optimal methods of soil remediation is relevant today. The question of probiotics uses for remediation contaminated soil is not enough studied in Ukraine. Wide use of probiotic is prevented by insufficient study of this area: deficiency of scientific and scientific-practical base, comparative studies of different probiotics, methods of calculating the required doses to obtain a given cleansing effect and more. Thus, there is a need for further studies of effects of petroleum products on plants and methods of remediation of contaminated soils with probiotics. The article evaluates the phytotoxicity of contaminated soil with petroleum products before and after cleaning with probiotics. To assess the phytotoxic effect of petroleum products were used indicators: seedling height, root length, phytomass of seedlings and phytomass of plants root system. In the experiment were used test-plants: peas (Pisum sativum), oats (Avéna satíva). Remediation of contaminated soil was performed by biological method using probiotic Sviteko-Agrobiotic-01 (dilution 1: 100). The probiotic was applied on the second day after petroleum contamination. The obtained results showed that petroleum products pollution has a different effect on peas and oats in different periods from the moment of pollution. Contaminated soil with petroleum products hadn’t significant phytotoxic effect on Pisum sativum seeds on the 2nd day after contamination. Оn the 30th day after contamination research results showed clear toxic effect on Pisum sativum seeds by concentration of petroleum products of 5000 and 10000 mg/kg; Оn the 180 days after contamination research results showed toxic effect on Pisum sativum seeds at all research concentrations. Contaminated soil with petroleum products had phytotoxic effect on Avéna satíva seeds on the 2nd day after contamination starting from the concentration of petroleum products 5000 mg/kg (such as decreasing the length of the roots and the ground part of plants). On the 30th and 180 th day after contamination petroleum products hadn’t toxic effect on Avéna satíva seeds in the all range of the studied concentrations. It was found that contaminated soil for Pisum sativum becomes toxic mostly on 30th day after the introduction of petroleum products and soil toxicity increase over the time. For Avéna satíva, the soil becomes toxic from the moment of contamination at concentrations of petroleum products 5000 mg/kg and the toxicity of the soil decreases over time. The research results confirmed the effectiveness of biological method (use probiotics) of cleaning the soil from petroleum products. It is established that probiotics clean the soil up to the 5th class of toxicity (no toxicity) at almost all concentrations of petroleum products. Only in the variant with Pisum sativum at concentration of petroleum products 20,000 mg/kg the phytotoxic effect was more than 20% (low toxicity). The average value of the efficiency of soil remediation from petroleum products by probiotics at sowing Pisum sativum was 75%, at Avéna satíva - 74%. Therefore, the experiment showed high efficiency of bioremediation from petroleum products in comparison with soil self-cleaning. On the basis of research results it is planned to develop methodical bases of complex system of remediation of technogenic polluted soils by the way of application of newest environmentally benign methods (using probiotic).

Biochar and Bacillus sp. MN54 Assisted Phytoremediation of Diesel and Plant Growth Promotion of Maize in Hydrocarbons Contaminated Soil

Contamination by petroleum hydrocarbons (PHs) is a great threat to environment due to the higher persistence and bio-toxicity of PHs. Therefore, removal of PHs from contaminated environment and strategies to reduce their toxic effects on living organisms are crucial for environmental safety and human health. The toxic effects of PHs from the polluted soil can be reduced by the addition of microbes and biochar. In this study, a pot trial was carried out to evaluate the effects of sugarcane bagasse (SB) biochar and Bacillus sp. MN54 addition on phytoremediation of PHs and growth of maize (Zea mays L.) in soil artificially contaminated with diesel. Maize seeds were sown in uncontaminated or contaminated (with PHs) soil, treated with biochar and Bacillus sp. MN54. The results revealed that PHs showed significant phytotoxicity to maize plants and the application of strain MN54 and biochar greatly reduced the toxic effects of PHs on plants growth and physiology by increasing the nutrients uptake in PHs contaminated soil. Interestingly, the phytotoxicity of PHs on maize plants was further reduced in the co-supplementation of strain MN54 and biochar. Plants physiological (25–48%) and agronomic (38–47%) attributes were significantly higher as compared to only PHs contaminated soil in the co-supplementation of strain MN54 and biochar. Similarly, nitrogen (41%), phosphorus (43%) and potassium (37%) concentrations were also increased in the co-supplementation of strain MN54 and biochar. Furthermore, maize plants successfully phytoremediate a considerable amount of PHs from soil particularly in the presence of strain MN54 and biochar, and this PHs removal was further enhanced in the co-supplementation of strain MN54 and biochar (i.e., 46% and 77% of initial PHs were removed in unplanted and planted treatments, respectively). The present results indicate that co-supplementation of biochar and Bacillus sp. MN54 could be effective in enhancing the degradation of PHs and improving plant growth in the hydrocarbons contaminated soil.

Phytotoxicity of petroleum hydrocarbons: Sources, impacts and remediation strategies

Extraction and exploration of petroleum hydrocarbons (PHs) to satisfy the rising world population's fossil fuel demand is playing havoc with human beings and other life forms by contaminating the ecosystem, particularly the soil. In the current review, we highlighted the sources of PHs contamination, factors affecting the PHs accumulation in soil, mechanisms of uptake, translocation and potential toxic effects of PHs on plants. In plants, PHs reduce the seed germination andnutrients translocation, and induce oxidative stress, disturb the plant metabolic activity and inhibit the plant physiology and morphology that ultimately reduce plant yield. Moreover, the defense strategy in plants to mitigate the PHs toxicity and other potential remediation techniques, including the use of organic manure, compost, plant hormones, and biochar, and application of microbe-assisted remediation, and phytoremediation are also discussed in the current review. These remediation strategies not only help to remediate PHs pollutionin the soil rhizosphere but also enhance the morphological and physiological attributes of plant and results to improve crop yield under PHs contaminated soils. This review aims to provide significant information on ecological importance of PHs stress in various interdisciplinary investigations and critical remediation techniques to mitigate the contamination of PHs in agricultural soils.

STABILITY OF PHYTOCENOSES IN OIL-PRODUCING REGIONS

The only real way to deal with the consequences of oil and oil products spills is a complex of works, including mechanical or physico-chemical removal of spilled oil products with subsequent purification of the remaining oil in the soil by biological methods using phytoremediation with oil-oxidizing plants. One of the stages of the study of hydrocarbon-oxidizing plants before their introduction into the environment for remediation of contaminated sites is the study of the process of degradation of pollutants in model soil systems. Model experiments on cleaning and restoration of soils after their contamination with oil and oil products by plant biomass were studied. Oil samples from the Tengiz field were taken. During the experiments, the indicator of the total amount of biomass, as well as the oil content in the soil, was controlled. To correctly assess the participation of plant raw materials in the destruction of oil, experiments were carried out using non-sterile soils. Among other plant cultures, the most degrading activity was shown by plant cultures of the genus Fabaceae, which led to an increase in growth in the soil environment by an average of 7 sm in 20 days. This is observed for plants with oil concentrations of 3, 6 and 9 g. The results of physical and chemical analyses of phytoremediation products of crude oil, petroleum products and individual aromatic hydrocarbons can be important in microbiological and chemical studies with geobotanical indicators that allow analyzing the mechanism of action of biomass in the process of phytoremediation in the disposal of oil waste that pollutes the environment. The available data on the effect of petroleum hydrocarbons on plants are very contradictory. The species diversity of plants capable of growing on oil-contaminated soils has not been sufficiently studied. Knowledge of the degree of resistance of plants to hydrocarbon pollution is necessary to address issues related, on the one hand, to the possibility of their cultivation on contaminated soil, and on the other - to use for the restoration of disturbed soil fertility. In connection with the above, it is of great scientific and practical interest to study the effect of various doses of oil on changes in vegetation cover, soil properties and assessment of their phytotoxicity, which together determines the relevance of the stated topic.

Effect of petroleum hydrocarbons on the carbon and nitrogen stable isotope composition of Nitzschia closterium

The microalgae is an important test organism of Petroleum hydrocarbon pollution. The present study was selected the N. closterium under laboratory conditions, the acute toxicity test of 180# fuel oil CE-WAF was investigated. We found the main content of the PAHs of CE-WAF were C0-N, C2-N, C1-N and C0-P by GC-MS analysis, indicating the toxicity of PAHs could affect the growth and development of microalgae. The EA-IRMS was used to analyze the carbon and nitrogen stable isotope composition of N. closterium under the CE-WAF stress. More importantly, the value of δ13C increased with the culture time at the control group, but there was no significant difference in δ13C value with increased culture time at the high (5%, 7%, and 10%) CE-WAF concentrations. In addition, the δ15N value of microalgae was increased in the culture time at the same CE-WAF concentration. However, there was no significant difference in δ15N value with increasing CE-WAF concentration at the same culture time. This study illustrated that the toxic effects of PAHs could be detected by the δ13C value to reveal the impact on marine ecosystems, and provided basic data and related theoretical support for marine pollution detection systems.

Изменение содержания белка у растений люцерны посевной Мedicago sativa L. под влиянием загрязнения почвы нефтью и рекультивации с применением препарата «Елена»

The study of the adaptive mechanisms of plants in response to the action of oil makes it possible to identify signs that ensure the resistance of plants in conditions of oil pollution, with the aim of using them in the development of methods of reclamation and selection of plants resistant to oil pollution for it. The available data on the effects of petroleum hydrocarbons on plants are highly controversial. The species diversity of plants capable of growing on oil-contaminated soils has not been sufficiently studied. Phytoremediation is the most suitable soil purification tool for agricultural areas due to the large extent of the land and the relative cheapness of the method. Physiological, biochemical and morphometric parameters are important indicators of plant resistance to hydrocarbon pollutants. Of great scientific and practical interest is the identification of the resistance of higher plants to exogenous petroleum hydrocarbons (HC) and the identification of the effect of phytoremediation and the effect of the introduction of biological products in case of hydrocarbon pollution of the soil. The aim of the work was to assess changes in the biochemical and morphometric parameters of Medicago sativa L. plants under conditions of soil pollution with oil and reclamation using the biological product "Elena". Determination of the protein content in leaves makes it possible to judge the status of nitrogen metabolism in plants. It was revealed that oil pollution led to a decrease in the protein content of the plant Medicago sativa L. The use of the biological product "Elena" led to the restoration of this parameter. The results showed that the positive effect of the studied biological product depends on the concentration of the pollutant.

Understanding the Impacts of Crude Oil and its Induced Abiotic Stresses on Agrifood Production: A Review

In many parts of the world, the agricultural sector is faced with a number of challenges including those arising from abiotic environmental stresses which are the key factors responsible for most reductions in agrifood production. Crude oil contamination, an abiotic stress factor and a common environmental contaminant, at toxic levels has negative impacts on plants. Although various attempts have been made to demonstrate the impact of abiotic stresses on crops, the underlying factors responsible for the effects of crude oil and its induced abiotic stresses on the composition of the stressed plants are poorly understood. Hence, this review provides an in-depth examination of the: (1) effect of petroleum hydrocarbons on plants; (2) impact of abiotic environmental stresses on crop quality; (3) mechanistic link between crude oil stress and its induced abiotic stresses; as well as (4) mode of action/plant response mechanism to these induced stresses. The paper clearly reveals the implications of crude oil-induced abiotic stresses arising from the soil-root-plant route and from direct application on plant leaves.

Особенности токсического действия углеводородов нефти на организм человека

Особенности токсического действия углеводородов нефти на организм человека

Effect of petroleum hydrocarbons in copper phytoremediation by a salt marsh plant (Juncus maritimus) and the role of autochthonous bioaugmentation

This work aimed to investigate, under controlled but environmental relevant conditions, the effects of the presence of both inorganic and organic contaminants (copper and petroleum hydrocarbons) on phytoremediation potential of the salt marsh plant Juncus maritimus. Moreover, bioaugmentation, with an autochthonous microbial consortium (AMC) resistant to Cu, was tested, aiming an increase in the remediation potential of this plant in the presence of a co-contamination. Salt marsh plants with sediment attached to their roots were collected, placed in vessels, and kept in greenhouses, under tidal simulation. Sediments were contaminated with Cu and petroleum, and the AMC was added to half of the vessels. After 5months, plants accumulated significant amounts of Cu but only in belowground structures. The amount of Cu was even higher in the presence of petroleum. AMC addition increased Cu accumulation in belowground tissues, despite decreasing Cu bioavailability, promoting J. maritimus phytostabilization potential. Therefore, J. maritimus has potential to phytoremediate co-contaminated sediments, and autochthonous bioaugmentation can be a valuable strategy for the recovery and management of moderately impacted estuaries. This approach can contribute for a sustainable use of the environmental resources. Graphical abstract ᅟ.

Histopathological changes in some tissues of Tigris river fishes, exposed to petroleum hydrocarbons, Baghdad city

During the period between January till December 2012, a total of 119 fish samples were collected and examined from Tigris River between Al-Jadiriya Bridge and Al-Zaafaraniya region in two stations, the first station was located under Al-Jadiriya bridge and the second station was located at Al-Zaafaraniya region before Diayla river in order to know the effects of petroleum hydrocarbons in the tissues of the examined fishes. Fish samples belonged to (16) species (Acanthobrama marmid, Albernus caeruleus, Aspius vorax, Barbua belayewi, B. grypus, B. xanthopterus, Carassius carassius, Carasobarbus luteus, Cyprinion macrostomum, Chondrostomua regium, Gara ruffa, Heteropneustes fossilis, Leuciscus cephalus, Liza abu, Mystus pelusius and Tilapia zillii). The histopathological examination included 44 specimens from the internal and external organs of Chontrostoma regium in order to examine the histopathological changes in some organs like (gills, muscles, kidney, liver and spleen). The results revealed congestion, edema, separating, severe vacuolation and dilation of gill secondary lamella, while muscle samples showed mild hyalinization, infiltration of mononuclear cells and fragmentation. The kidney showed hydropic degeneration, necrosis changes, hyperplastic of melanomacrophages, severe dilation of blood vessels with cellular swelling of renal tubule epithelial lining and depletion of hemopoiotic tissues. Severe dilation and congestion of blood vessels and sinusoid, nucleopleomorphism were noticed with nucleomegalocytic of hepatocytes, hemorrhagic with mineral deposition in hepatic parenchyma. Lymphoid depletion in white pulp and hemopoitic tissues, congestion of red pulp, severe hyperplasia were noticed with dilation of splenic tissues. Water samples from Tigris river were analyzed for measuring the level of petroleum hydrocarbons in water and appeared that the pollution 0.0048 mg/L in Al-Jadiriya station and 0.0674 mg/L in Al-Zaafaraniya station.

The Effects of Petroleum Hydrocarbons on Algae Can Be Reversed in the Presence of a Primary Consumer.

The ecotoxicological effects of a mixture of petroleum hydrocarbons were tested on densities of two algae, Platymonas helgolandica var. tsingtaoensis and Isochrysis galbana, and of a rotifer, Brachionus plicatilis, by single-species and customized community experiments. Test concentrations ranged from 0 to 100 mg L(-1), while five to seven treatments were assessed in triplicate within 1 month. A significant decrease in densities during single-species toxicity tests were found when concentrations of petroleum hydrocarbons were above 1.0 mg L(-1). However, equilibrium densities of algae in the customized community showed a different pattern, which increased with concentration and reached a peak at 20.0 mg L(-1). The community-based no observed effect concentration (NOEC; 1.0 mg L(-1)) was different from the NOEC derived by single-species toxic tests (0.25 mg L(-1)). This demonstrates that ecotoxicological effects on plankton as part of a community is significantly different from single-species toxicity tests owing to ecological interactions.

Toxicity of fuel-contaminated soil to Antarctic moss and terrestrial algae.

Fuel pollution is a significant problem in Antarctica, especially in areas where human activities occur, such as at scientific research stations. Despite this, there is little information on the effects of petroleum hydrocarbons on Antarctic terrestrial biota. The authors demonstrate that the Antarctic mosses Bryum pseudotriquetrum, Schistidium antarctici, and Ceratodon purpureus, and the Antarctic terrestrial alga Prasiola crispa are relatively tolerant to Special Antarctic Blend (SAB) fuel-contaminated soil (measured as total petroleum hydrocarbons). Freshly spiked soils were more toxic to all species than were aged soils containing degraded fuel, as measured by photosynthetic efficiency (variable fluorescence/maximum fluorescence [Fv/Fm]), pigment content, and visual observations. Concentrations that caused 20% inhibition ranged from 16,600 mg/kg to 53,200 mg/kg for freshly spiked soils and from 30,100 mg/kg to 56,200 mg/kg for aged soils. The photosynthetic efficiency of C. purpureus and S. antarctici was significantly inhibited by exposure to freshly spiked soils with lowest-observed-effect concentrations of 27,900 mg/kg and 40,400 mg/kg, respectively. Prasiola crispa was the most sensitive species to freshly spiked soils (Fv/Fm lowest-observed-effect concentration 6700 mg/kg), whereas the Fv/Fm of B. pseudotriquetrum was unaffected by exposure to SAB fuel even at the highest concentration tested (62,900 mg/kg). Standard toxicity test methods developed for nonvascular plants can be used in future risk assessments, and sensitivity data will contribute to the development of remediation targets for petroleum hydrocarbons to guide remediation activities in Antarctica.

Synergism of Wild Grass and Hydrocarbonoclastic Bacteria in Petroleum Biodegradation

Synergism of Wild Grass and Hydrocarbonoclastic Bacteria in Petroleum Biodegradation

Phytoremediation of hydrocarbon-contaminated soils with emphasis on the effect of petroleum hydrocarbons on the growth of plant species

To date, many developing countries such as Iran have almost completely abandoned the idea of decontaminating oil-polluted soils due to the high costs of conventional (physical/chemical) soil remediation methods. Phytoremediation is an emerging green technology that can become a promising solution to the problem of decontaminating hydrocarbon-polluted soils. Screening the capacity of native tolerant plant species to grow on aged, petroleum hydrocarbon-contaminated soils is a key factor for successful phytoremediation. This study investigated the effect of hydrocarbon pollution with an initial concentration of 40 000 ppm on growth characteristics of sorghum (Sorghum bicolor) and common flax (Linum usitatissumum). At the end of the experiment, soil samples in which plant species had grown well were analyzed for total petroleum hydrocarbons (TPHs) removal by GC-FID. Common flax was used for the first time in the history of phytoremediation of oil-contaminated soil. Both species showed promising remediation efficiency in highly contaminated soil; however, petroleum hydrocarbon contamination reduced the growth of the surveyed plants significantly. Sorghum and common flax reduced TPHs concentration by 9500 and 18500 mg kg‑1, respectively, compared with the control treatment.

RESPIROMETRIC STUDIES ON THE IMPACT OF HUMIC SUBSTANCES ON THE ACTIVATED SLUDGE TREATMENT: MITIGATION OF AN INHIBITORY EFFECT CAUSED BY DIESEL OIL

This paper describes the results of aerobic respirometric studies on the application of humic substances (humate) to mitigate an inhibitory effect of petroleum hydrocarbons (diesel oil) on the returned activated sludge (RAS) in sewage from a municipal treatment plant. Initial results of the respirometric tests and non‐linear regression analysis showed that diesel oil had an inhibitory effect on the activity of biomass and that kinetic data complied with the Haldane model for inhibitory wastes. Humate addition significantly enhanced the oxygen uptake by RAS. Application of humate at the dose of 2000 mg l−1 to the sewage contaminated with 10 mg l−1 of diesel oil resulted in almost complete recovery of the biomass oxygen uptake. Non‐linear regression analysis of the respirometric data indicated that this system complied with the Monod model for non‐inhibitory wastes. Thus, the application of humic substances to mitigate the inhibitory effects of oil spills in wastewater treatment plants seems to be an attractive alternative to the treatments using activated carbon or specialized sorbents.

Arbuscular mycorrhizal fungi in chronically petroleum‐contaminated soils in Mexico and the effects of petroleum hydrocarbons on spore germination

Arbuscular mycorrhizal fungi (AMF) have been hypothesized to enhance plant adaptation and growth in petroleum-contaminated soils. Nevertheless, neither AMF-biodiversity under chronically petroleum-contaminated soils nor spore germination response to petroleum hydrocarbons has been well studied. Chronically petroleum-contaminated rhizosphere soil and roots from Echinochloa polystachya, Citrus aurantifolia and C. aurantium were collected from Activo Cinco Presidentes, Tabasco, Mexico. Root colonization and spore abundance were evaluated. Additionally, rhizosphere soil samples were propagated using Sorghum vulgare L. as a plant trap under greenhouse conditions; subsequently, AMF-spores were identified. AMF-colonization ranged from 63 to 77% while spore number ranged from 715 to 912 in 100 g soil, suggesting that AMF tolerate the presence of petroleum hydrocarbons in the rhizosphere. From grass species, four AMF-morphospecies were identified: Glomus ambisporum, G. sinuosum (previously described as Sclerocystis sinuosum), Acaulospora laevis, and Ambispora gerdermanni. From citrus trees, four AMF-species were also identified: Scutellospora heterogama, G. ambisporum, Acaulospora scrobiculata, and G. citricola. In a second study, it was observed that spore germination and hyphal length of G. mosseae, G. ambisporum, and S. heterogama were significantly reduced by either volatile compounds of crude oil or increased concentrations of benzo[a ]pyrene or phenanthrene in water-agar.

Assessment of the effects of hydrocarbon contamination on the sedimentary bacterial communities and determination of the polar lipid fraction purity: Relevance of intact phospholipid analysis

This in situ study reports on the relevance of intact phospholipids as new biomarkers and highlights the limits of the classical fatty acid analysis after the hydrolysis of the polar lipid fraction. The analysis of polar lipid fractions revealed significant contributions of marine macrophytes with either non-phospholipid compounds (sulfoquinovosyl diacylglycerol) or with both non-bacterial phospholipid classes (phosphatidylcholine) and non-bacterial phospholipid molecular species (some molecular species of phosphatidylglycerol). The analysis of intact phospholipids showed also the predominance of gram-negative bacteria in sediments whereas the analysis of fatty acids alone cannot confirm such information. Lastly, as regard to the effects of petroleum hydrocarbons on the sedimentary bacterial communities, we observed a higher degree of saturation of the fatty acyl chains of the phospholipids extracted from sediment exposed to a massive and chronic crude oil contamination. Such a result was interpreted as an adaptive response resulting in higher membrane rigidity of the bacterial communities.

Effects of crude oil on phospholipid fatty acid compositions of marine hydrocarbon degraders: estimation of the bacterial membrane fluidity

In this study, we investigated, in vitro, the effects of petroleum hydrocarbons on the phospholipid ester-linked fatty acid composition of Corynebacterium sp. Strain 8. The usual ratio of monounsaturated fatty acids E/Z (or trans/cis) was calculated. This ratio led to unexpected results because we found similar values for growths on either a hydrophobic substrate (crude oil) or a soluble carbon source (rich medium). The use of such an indicator seemed limited for monitoring an environmental stress, so we proposed an index based on the homeoviscous adaptation theory. A membrane viscosity index was defined and applied to Corynebacterium sp. Strain 8 (in vitro growth) and to a sedimentary community (in situ experiment). The results allowed us to estimate the membrane fluidity of both an isolated strain and a bacterial community in accordance with the medium hydrophobicity.

Effects of petroleum hydrocarbons on the phospholipid fatty acid composition of a consortium composed of marine hydrocarbon-degrading bacteria

Phospholipid ester-linked fatty acids (PLFAs) of a bacteria consortium, reconstituted in vitro from ten marine hydrocarbon-degrading bacteria, were studied. Culture of the consortium with ammonium acetate as the sole carbon source mainly yielded even-numbered PLFAs composed of straight chain saturated (ca. 26%) and monounsaturated (ca. 71%) fatty acids. Growth of the consortium on Blend Arabian Light petroleum (BAL 250) resulted in a complex PLFA profile with the appearance of (1) odd-numbered straight chain PLFAs, mainly 15:0 and 17:0, (2) iso- and anteiso-PLFAs with 15–17 carbon atoms, (3) 10-, 11-, 12- and 13-monomethylated PLFAs with 16–19 carbon atoms and (4) odd-numbered monounsaturated PLFAs, mainly 17:1 Δ9Z and 19:1 Δ10. When petroleum grown cells were transferred into a medium containing ammonium acetate, the consortium exhibited mainly even-numbered PLFAs: this demonstrated the ability of bacterial strains to restore their PLFA compositions after exposure to petroleum hydrocarbons. It, therefore, appears that the PLFA compositions of these bacteria are strongly influenced by the carbon sources so that several potential biomarkers of hydrocarbon-degrading bacterial activities could be recognized. In addition, an hydrocarbon-degrading activity index (HDAI) was derived from the characteristic PLFA profiles of the consortium grown on ammonium acetate and petroleum hydrocarbons. The HDAI may prove to be a tool revealing the development of hydrocarbon-degrading strains in oil-contaminated sediments.