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1.
Crude oil and water samples were collected from selected Iranian oil reservoirs. Experimental works were carried out in laboratory conditions. The samples have been grown on PYG medium and incubated at 30–80 °C. Thirty-six mesophile and thermophile bacterial strains have been isolated. All the isolates were able to grow at aerobic condition. Batch growth kinetic studies were carried out in a 500 ml. shake flask. Out of 36 isolated strains from 24 crude oil and water samples, 35 strains were gram positive rod. Shaped spore forming bacteria and one strain was coccid form. Eight out to 35 bacillus species were capable of producing surfactant. Production of biosurfactant was found to be cell growth associated. The ability of surfactant producing bacteria indicated by reduction of surface tension (ST) and interfacial tension (IFT) of the supernatant. Eight strains obtained the IFT reduction in crude oil, hexadecane, sucrose, glucose, fructose and mannose medium as a sole source of carbon and energy at 40 °C by 15–30 mN/m. Results showed that all the bacteria are producing more surfactant when glucose is the carbon source. Further screening of biosurfactant producer showed that three of the isolated strains resulted the maximum ST and IFT. Effect of temperature on these three isolates investigated at 30–80 °C, above 50 °C surfactant production was dramatically reduced. The isolated strains had the capacity to produce the surfactant at 3–5% NaCl a wide rang of pH (6.5–8.5).  相似文献   

2.
Biodegradation of petroleum hydrocarbons as a decontamination mechanism is a relatively slow process. This study aimed to investigate the impact of a tailored consortium of bacteria with higher capacities in biosurfactant production and biodegradation on the acceleration of the biodecontamination process. To this end, 18 biosurfactant producing bacteria were isolated from the crude oil-contaminated soil samples of Isfahan refinery, and the activity of the produced biosurfactants was measured in terms of surface tension reduction and emulsification E24 test. Then, the isolates screened for the biodegradation of kerosene hydrocarbons and chemical structure of the purified biosurfactants produced by the most efficient isolates were partially characterized. Next, the isolates were sorted based on their surfactant activity and biodegradation efficiency, and the higher ranked bacteria thus selected were utilized to form an efficient consortium removing hydrocarbons from the oil-contaminated soil samples in a slurry phase system. The consortium consisted of Bacillus subtilis tb1 and Pseudomonas aeruginosa species having the highest biodegradation capabilities and surface activities. The results revealed that the hydrocarbon removal efficiency of the consortium was at least 25 % higher than single species, and the final removal efficiency for the consortium could be reached in a considerably shorter time.  相似文献   

3.
The ability of native bacteria to utilize diesel fuel as the sole carbon and energy source was investigated in this research. Ten bacterial strains were isolated from the oil refinery field in Tehran, Iran. Two biodegradation experiments were performed in low and high (500 and 10000 ppm, respectively) concentration of diesel fuel for 15 days. Only two isolates were able to efficiently degrade the petroleum hydrocarbons in the first test and degraded 86.67% and, 80.60 % of diesel fuel, respectively. The secondary experiment was performed to investigate the toxicity effect of diesel fuel at high concentration (10000 ppm). Only one strain was capable to degrade 85.20 % of diesel fuel at the same time (15 days). Phenotype and phylogeny analysis of this strain was characterized and identified as diesel-degrading bacteria, based on gram staining, biochemical tests, 16S rRNA gene sequence analysis. These results indicate that this new strain was Bacillus sp. and could be considered as Bacillus Cereus with 98 % 16 S rRNA gene sequence similarity. The results indicate that native strains have great potential for in situ remediation of diesel-contaminated soils in oil refinery sites.  相似文献   

4.
Nocardia otitidiscaviarum microbial type cultural collection 6471 isolated from oil contaminated Alang India seawater was examined for production of surface active compound. Isolate shows halos and α-heamolysis on cetyl trimethyl ammonium bromide and blood agar respectively indicating the production of biosurfactant. Biosurfactant was extracted by precipitation and was partially purified. Partially purified product was characterized by thin layer chromatography and Infra-red spectroscopy and was identified as glycolipid. Sugar present in glycolipid was rhamnose and hence, biosurfactant was quantified as rhamnose equivalent. Role of cell-surface hydrophobicity and emulsification activity in correlation with biosurfactant production was examined. Correlation between biosurfactant production, growth and crude oil degradation was also examined and showed positive correlation at significant level 0.001 and 0.01 respectively. Thus, this is a first report on a marine strain of Nocardia otitidiscaviarum microbial type culture collection 6471, which can be a potential candidate for restoration of oil contaminated marine environment.  相似文献   

5.
Crude oil and its derivatives because of different events and accidents may cause pollution to the environment. A biological treatment is a novel technique that uses microorganisms to remove or neutralize pollutants from a contaminated site. Oil-contaminated soils were sampled, after isolating of soil bacteria, using quantitative and qualitative screening, biosurfactant-producing bacteria were identified and environmental factors on the growth of bacteria and biosurfactant were investigated. In this study, the Bacillus subtilis was identified as the best biosurfactant-producing strain which has the ability to grow in environments with high salinity and temperature and pH > 5. The produced biosurfactant from B. subtilis is stable to changes in temperature and salt concentration and pH (in the range of 5–12).The B. subtilis also showed that they are able to biodegrade aliphatic alkanes. The B. subtilis has necessary potential for bioremediation of oil pollution in the environment.  相似文献   

6.
This research work focuses on testing the bacterial strain Bacillus licheniformis for the bioremediation capacity of the crude oil. A biosurfactant and two different nanoparticles with different concentrations (0.05, 0.1, 0.2 g/100 ml) were applied separately to enhance the biodegradation process. The optimum biodegradation of crude oil was demonstrated at 60% of microcosms containing biosurfactant and nanoparticles after 7 days. The bacterial strain is highly potential to consume the total paraffins (iso- and n-paraffins) in crude oil samples. Accordingly, the best biodegradation of total paraffins was observed in microcosms containing (0.2 g) of Fe2O3, Zn5(OH)8Cl2 (nps) and biosurfactant separately. Additionally, the consumption of specific member rings of polyaromatics depends on the type and the concentration of nanoparticles. Thus, this bacterial strain was considered as a good candidate to be applied in the bioremediation process of petroleum-contaminated sites using biosurfactant and specific concentration of (Fe2O3 and Zn5OH8Cl2) nanoparticles.  相似文献   

7.
1, 3, 5-TMB (trimethylbenzene) has been considered as priority pollutant by several environmental agencies due to its high toxicity, carcinogenicity and mutagenic activity. Two bacteria with ability of degrading 1, 3, 5- TMB were isolated from crude oil contaminated soil. The optimal pH value and temperature for the growth of these bacteria were 7.0 and 30℃. 1, 3, 5- TMB was used as sole carbon and energy source by both strains. Strain A was identified as Staphylococcus sciuri and Strain C was Microbacterium schleiferi, both of which were facultative anaerobic bacteria. 1, 3, 5-TMB was degraded by strain C with efficiency of 41.2±1.8%. The bacteria offered new source for biodegradation of BTEX and bioremediation of oil-contaminated soil and groundwater.  相似文献   

8.
Onshore and offshore oil spills contaminate soil. In addition to environmental concerns for ground water pollution and other possible effects, the geotechnical properties of the contaminated soil such as the shear strength and the hydraulic conductivity are also altered. This note is a report of research in progress to evaluate the variation of the shear strength of a sand contaminated by a crude oil and thus the ultimate bearing capacity of shallow foundations. The limited results of the tests reported here relate to only one type of sand and one crude oil. The oil content was varied from zero to 4.2%. Results of direct shear tests for determining the soil friction angle are given. Along with these, laboratory model test results for the ultimate bearing capacity of a surface strip foundation supported by crude oil-contaminated sand are also presented. Based on these test results, the effect of oil contamination in drastically reducing the bearing capacity is discussed.  相似文献   

9.
Surfactants enhanced recovery of endosulfan from contaminated soils   总被引：1，自引：1，他引：1  
Soil pollution due to hydrophobic organic compounds is a wide environmental problem. Extensive use of endosulfan in cotton and paddy to meet the needs of the growing population has led to contamination of soil and other ecosystems. Endosulfan is hydrophobic, highly toxic to aquatic and human population and persists in soil for more than a year. To overcome the problem of hydrophobicity and limited availability, surfactants play a major role in soil remediation. In the present study, the potential of non-ionic synthetic surfactants (Tween 80, Triton X-100) and biosurfactant (Surfactin produced by Bacillus subtilis) for enhancing the release of endosulfan from contaminated agricultural soils was evaluated using the batch method. Incorporation of the surfactant concentrations at above Criticle Miceller Concentration (0.5, 1 and 2 g/L) into soil enhances the release of endosulfan. Surfactin produced from Bacillus subtilis recorded maximum (91.5%) recovery. The observed order of recovery being surfactin > Tween 80 > Triton X-100. The result suggest that surfactants could help in the remediation of soils polluted by pesticides.  相似文献   

10.
广西北部湾人造陆域吹填土生物固结试验研究   总被引：2，自引：0，他引：2  
结合微生物对岩土工程特性影响的研究现状,选取黑曲霉、放射型土壤杆菌及地衣芽孢杆菌3株菌种,首先通过压缩试验研究了不同微生物菌种及其培养液掺入土样后对土样固结特性的影响情况,然后借助矿物和化学成分分析及土粒比表面积测定等手段,初步探索微生物改良吹填土机制。研究表明,掺入微生物菌种及其培养液后土样的压缩系数av1-2均有降低,压缩模量Es1-2均有增加,最大降幅和升幅分别为29%和37%;土样的矿物成分没有改变;土中高价阳离子明显减少,但这不是造成土体压缩特性变化的主因;掺入放射型土壤杆菌、地衣芽孢杆菌后土样土粒的比表面积分别增大到1.49倍、1.45倍,菌株改变了土颗粒间的连接状态,从而导致土体颗粒的增多或者土体结构的变化。  相似文献   

11.
利用从油藏中分离的芽孢杆菌HBS4在兼性厌氧情况下作用于剧毒物质亚硒酸钠,36 h后1～11mM的样品中均出现了大量红色颗粒沉淀物.生物显微镜观察发现,在很多细菌内部出现一颗到多颗红色的圆形颗粒,排列方式有单链、双链、弧线和无规则排列,并且在细胞周围释放有游离态的红色颗粒.XPS测试红色沉淀物发现四价硒全部还原为零价硒.实验还发现添加葡萄糖对单质硒的产量有很大的促进作用.  相似文献   

12.
The aim of this study was to assess the antimicrobial resistance and the prevalence of genes determining the presence of extended-spectrum beta-lactamase (ESBL) enzymes in Escherichia coli isolated from two major rivers of the Podhale region in southern Poland. In total, 196 E. coli isolates were analyzed—98 from each river—Bia?ka and Zakopianka, collected in 8 campaigns, over the period of two years. Antimicrobial resistance was assessed using disk diffusion method and PCR tests were conducted to detect the ESBL genes. In E. coli isolated from Bia?ka, the resistance to amoxicillin/clavulanic acid was detected most frequently (54.08%) and ESBL was detected in 14.29% of strains. In strains isolated from Zakopianka, most frequent resistance was observed toward ticarcillin (51.02%), while ESBL was observed in 16.33% of isolates. In the total pool of isolates, the resistance to amoxicillin/clavulanic acid was most frequent (48.98% of isolates) and ESBL producers comprised 15.30% of E. coli isolates derived from both rivers. Multidrug resistance was observed less frequently in strains derived from Bia?ka (4 isolates resistant to 10 and more antimicrobials) than from Zakopianka, where 10 isolates were resistant to 10 and more antibiotics. Out of the tested ESBL genes blaTEM was detected most frequently (45.4% of isolates), whereas blaCTX-M1 and blaCTX-M3 were recorded in one isolate.  相似文献   

13.
Different bacterial and fungal strains, isolated from petroleum hydrocarbon-contaminated soil, were tested, in isolation as well as in combination, for their ability to degrade total petroleum hydrocarbon (TPH) in soil samples spiked with crude oil (2, 5 or 10 %, w/w) for 30 days. The selected combination of bacterial and fungal isolates, i.e., Pseudomonas stutzeri BP10 and Aspergillus niger PS9, exhibited the highest efficiency of TPH degradation (46.7 %) in soil spiked with 2 % crude oil under control condition. Further, when this combination was applied under natural condition in soil spiked with 2 % (w/w) crude oil along with inorganic fertilizers (NPK) and different bulking agents such as rice husk, sugarcane, vermicompost or coconut coir, the percent degradation of TPH was found to be maximum (82.3 %) due to the presence of inorganic fertilizers and rice husk as bulking agent. Further, results showed that the presence of NPK and bulking agents induced the activity of degradative enzymes, such as catalase (0.718 m mol H2O2 g?1), laccase (0.77 µmol g?1), dehydrogenase (37.5 µg g?1 h?1), catechol 1, 2 dioxygenase (276.11 µ mol g?1) and catechol 2, 3 dioxygenase (15.15 µ mol g?1) as compared to control (without bioaugmentation). It was inferred that the selected combination microbes along with biostimulants could accentuate the crude oil degradation as evident from the biostimulant-induced enhanced activity of degradative enzymes.  相似文献   

14.
The southern coastal plain of Iran at the Persian Gulf encounters oil pollution due to the historical oil exploitation, related tanker navigations and accidents, and petrochemical industrial expansions in the recent years. Therefore, it is important to investigate the geochemical properties of oil-contaminated coastal soils and sediments for engineering and environmental purposes. Here, an extensive laboratory testing program was carried out to determine the effects of crude oil contamination on some of the geotechnical properties of clayey and sandy soils such as CL, SM and SP sampled from the coastal soils from this area. The testing included basic properties, Atterberg limits, compaction, direct shear, uniaxial compression and permeability tests on clean and contaminated soil samples at the same densities. The contaminated samples were prepared by mixing the soils with crude oil in the amount of 2%, 4%, 8%, 12%, and 16% by dry weight. The results indicated a decrease in strength, permeability, maximum dry density, optimum water content and Atterberg limits. Knowledge of these effects of oil contamination is important in coastal engineering and environmental remediation activities of the studied coastal plain.  相似文献   

15.
Waste engine oil causes a vital environmental pollution when it spill during change and transportation and products of waste engine oil causes lethal effects to the living systems. Thus, abiotic and biotic approaches are being extensively used for removal of waste engine oil pollution. Therefore in present study, waste engine oil degradation was accomplished by a new bacterial culture, isolated from the soil by an enrichment technique. Morphological, biochemical and gene sequence analysis revealed that isolate was Bacillus cereus. Subsequently, biodegradation potential of B. cereus for waste engine oil was studied. Experimental variables, such as pH, substrate concentration, inoculum size, temperature and time on the biodegradation, were checked in mineral salt medium. The biodegradation efficiency of B. cereus was determined by gravimetry, UV–visible spectrophotometry and gas chromatography. In addition, waste engine oil was also characterized by GC–MS and FTIR for its major constituents, which showed total 38 components in waste engine oil, including hopanes, benzopyrene, long-chain aliphatic hydrocarbons, dibenzothiophenes, biphenyl and their derivatives. Results of successive biodegradation indicated that B. cereus was capable to degrade 1% of waste engine oil with 98.6% degradation potential at pH 7 within 20 days. Hence, B. cereus presents an innovative tool for removing the engine oil from the contaminated area.  相似文献   

16.
The characteristics of hydrocarbon-contaminated soils have been among major concerns of geotechnical engineers due to its significant frequency of event and also its influential consequences on our surroundings from various environmental and engineering viewpoints. Heretofore, the effects of diverse kinds of hydrocarbon contaminants on majority of geotechnical properties of fine- and coarse-grained soils such as grain size, hydraulic conductivity, plasticity, compressibility, internal friction, cohesion, and shear strength have been investigated. However, there has not been a concentrated research study examining shear wave velocity (\({\text{V}}_{\text{s}}\)) of hydrocarbon-contaminated soils as an important geotechnical property of soil due to this fact that, in small/very small strain levels, the maximum shear modulus of soils (\({\text{G}}_{ \hbox{max} }\)) can be determined using shear wave velocity (\({\text{G}}_{ \hbox{max} } =\uprho{\text{V}}_{\text{s}}^{2}\)). This paper aims to investigate effects of hydrocarbon contamination on shear wave velocity of sandy soils by comparing shear wave velocities in identically prepared clean and contaminated samples. To this aim, an Iranian light crude oil, a standard type of silica sand (Ottawa sand), and a bender element apparatus were used to minutely measure shear wave velocity of clean and crude oil contaminated sand samples. Moreover, dry and quasi-moist tamping methods were employed in order to provide comparable clean and contaminated specimens (containing 4, 6, 8, 10, and 12 wt% of crude oil), respectively. Firstly, a comprehensive bender element (BE) and resonant column tests were conducted on the identically prepared clean sand samples at various amounts of frequency (2–20 kHz) and under various confining pressure (50–500 kPa) to find the best methods of accurately determining shear wave travel time in BE tests. Thereafter, BE tests were conducted to examine shear wave velocity in contaminated specimens. Based on the results, it was found that there was a critical value for crude oil content with the maximum shear wave velocity so that shear wave velocity of 4 wt% contaminated sand (Vs-4 wt%) was about 1.2 times higher than clean one (Vs-clean), and contrastingly adding further crude oil up to 6 wt% made a significant reduction in value of shear wave velocity to some extent that Vs-6 wt% was slightly lower than Vs-clean (Vs-6 wt% = 0.95–0.97Vs-clean). Moreover, adding more contaminant (8–12 wt%) into sand had negligible influences on shear wave velocity. In this paper, the effects of crude oil contamination on sand microstructure were also evaluated using scanning electron microscopy.  相似文献   

17.
The lipA gene, encoding a solvent-tolerant extracellular lipase from Proteus sp. SW1, was displayed on the cell surface of Escherichia coli by fusing it to an antigen 43 anchoring motif. The display of LipA on the Escherichia coli cell surface was directly confirmed by immunofluorescence microscopy and flow cytometry. After 6 days of incubation in media containing 1 % used cooking oil, an Escherichia coli strain expressing surface displayed lipase was able to degrade 27 % of the oil. The biosurfactant, pseudopyronine B, was purified from culture supernatants of Pseudomonas sp. SL31. Its critical micelle concentration was determined to be 1400 mg/l, and the surfactant was stable within a temperature range from 0 to 120 °C and a pH range of 3–11. Pseudopyronine B-containing crude media extracts efficiently removed up to 51 % of the cadmium from contaminated water. We demonstrated the oil degradation ability of the mixed culture of four bacterial strains, namely the recombinant Escherichia coli expressing cell surface displayed lipase (pKKJlipA), His-tagged lipase (pETlipA), extracellular lipase-producing Proteus sp. SW1, and pseudopyronine B-producing Pseudomonas sp. SL31 by culturing in LB media containing 1 % oil. The consortium degraded 29 % of oil in one day and reached 84 % after 7 days.  相似文献   

18.
Soil pollution by crude oil is a challenging environmental issue for oil producing countries. Several methods have been developed for remediation of the contaminated soil including washing with different detergents. In this work, we applied UTCHEM simulator model to the sand columns polluted by 10000 and 30000 ppm of crude oil which was treated with 0.05, 0.1 and 0.2 wt% of a biological detergent, saponin. The results showed a good agreement between simulated and pilot study. The maximum remediation was 61% with a pH of 9 when we utilized 0.2 wt% saponin for the column contaminated with 30000 ppm of crude oil. 47% remediation was achieved with a pH of 9 when 0.1wt% of detergent was applied to the same column. Sensitivity analysis indicated an increase in remediation by increasing the pH with the optimum pH of 11. The best possible concentrations of surfactant solutions were 0.1 and 0.2 wt% for 10000 and 30000 ppm pollution, respectively, resulting in crude oil removal efficiencies of 69% and 72%, respectively. Simulation results also indicated that an increase in the permeability of the sand columns would also result in an increased remediation.  相似文献   

19.
文茜  赵亮  石玉兰  杨思忠 《冰川冻土》2014,36(5):1306-1312
生物降解与土著微生物群落结构、功能及其变化密切相关. 目前, 对于东北冻土土壤中的适冷降解菌了解不足. 新建成的中俄输油管道穿越中国东北的多年冻土区, 为相关研究提供了契机. 实验利用454高通量测序分析了加格达奇冻土活动层土壤在受控原油污染前后的微生物群落结构. 结果显示: 污染后的Proteobacteria和Firmicutes相对丰度显著升高, 优势类群包括Alicyclobacillus、Sphingomonas、Nevskia以及Bacillus. 群落以芳烃降解菌或者耐受油污环境的细菌为主. 这种变化与原油(尤其是芳烃)组分的生态毒害作用有关. 较高浓度的原油污染下, 群落中可耐受油污环境的细菌丰度相对更高.  相似文献   

20.
The aim of this research was to evaluate the potential of six legumes: Medicago sativa L., Glycine max, Arachis hypogea, Lablab purpureus, Pheseolus vulgaris and Cajanus cajan to restore within a short period of time soil contaminated with 3% crude oil. The legumes in five replications were grown in crude oil-contaminated and crude oil-uncontaminated soil in a completely randomized design. Plants were assessed for seedling emergence, plant height and leaf number. GC–MS was used to analyze the residual crude oil from the rhizosphere of the legumes. Plant growth parameters were reduced significantly (P < 0.05) for legumes in contaminated soil compared to their controls. In the 4th week after planting (WAP), shoot height increased across the species up to the 8th WAP. However, in the 12 WAP no significant increase in the shoot of all species was observed. Two WAP legumes planted in contaminated soil had significantly (P < 0.05) higher leaf number than these planted in uncontaminated soil with the exception of M. sativa. In the 4th WAP, only A. hypogea and P. vulgaris had increased leaf number, while in the 6th WAP, only L. purpureus had increased leaf number and survived up to the 12th WAP while most of the legumes species died. Chromatographic profiles indicated 100% degradation of the oil fractions in C. cajan and L. purpureus after 90 days. For other legumes however, greater losses of crude oil fractions C1–C10 and C10–C20 were indicated in rhizosphere soil of P. vulgaris and G. max, respectively. The most effective removal (93.66%) of C21–C30 components was observed in G. max-planted soil even though vegetation was not established. The legumes especially C. cajan, L. purpureus and A. hypogea are promising candidates for phytoremediation of petroleum hydrocarbon-impacted soil.  相似文献   

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