Petroleum-degrading Bacteria Research Articles

Bioremediation of petroleum-contaminated soil using aged refuse from landfills

This study explored the effects and mechanisms of petroleum-contaminated soil bioremediation using aged refuse (AR) from landfills. Three treatments of petroleum-contaminated soil (47.28 mg·g−1) amended with AR, sterilized aged refuse (SAR) and petroleum-contaminated soil only (as a control) were tested. During 98 days of incubation, changes in soil physicochemical properties, residual total petroleum hydrocarbon (TPH), biodegradation kinetics, enzyme activities and the microbial community were investigated. The results demonstrated that AR was an effective soil conditioner and biostimulation agent that could comprehensively improve the quality of petroleum-contaminated soil and promote microbial growth, with an 74.64% TPH removal rate, 22.36 day half-life for SAR treatment, compared with the control (half-life: 138.63 days; TPH removal rate: 22.40%). In addition, the petroleum-degrading bacteria isolation results demonstrated that AR was also a petroleum-degrading microbial agent containing abundant microorganisms. AR addition significantly improved both the biotic and abiotic conditions of petroleum-contaminated soil without other additives. The cooperation of conditioner addition, biostimulation and bioaugmentation in AR treatment led to better bioremediation effects (half-life: 13.86 days; TPH removal rate: 89.83%). In conclusion, AR amendment is a cost-effective, easy-to-use method facilitating in situ large-scale application while simultaneously recycling huge amounts of AR from landfills.

Breeding of in-situ Petroleum Degrading Bacteria in Hangzhou Bay and evaluating for the In-situ repair effect

In this paper, the restoration behaviour of the in-situ microorganisms in seawater and sediments to the marine accident oil spill was researched. The experimental study on the breeding of in-situ petroleum-degrading bacteria in the seawater and sediments of Hangzhou Bay and the restoration of oil spill were carried out. Making use of the reinforced microbial flora, combined with physical and chemical methods in field environment, petroleum degrading and restoration experiment were performed, the effect of the breeding of in-situ degrading bacteria was evaluated, and the standard process of in-situ bacteria sampling, laboratory screening, domestication and degradation efficiency testing were formed. This study laid a foundation for further evaluation of the advantages and disadvantages for the petroleum-degrading bacteria of Hangzhou Bay during the process of in-situ restoration. The results showed that in-situ microbes of Hangzhou Bay could reach the growth peak in 5 days with the suitable environmental factors and sufficient nutrient elements, and the degradation efficiency could reach 65.2% (or 74.8% after acclimation). And also the microbes could adapt to the local sea water and environmental conditions, with a certain degree of degradation. The research results could provide parameter support for causal judgment and quantitative assessment of oil spill damage.

Performance and community structure change of immobilized marine petroleum-degrading bacteria in the degradation process

Performance and community structure change of immobilized marine petroleum-degrading bacteria in the degradation process

Remediation of Petroleum-Contaminated Soil Using a Bioaugmented Compost Technique

Bioaugmented compost was created by inoculating petroleum-degrading bacteria into mature compost. The petroleum hydrocarbon degradation efficiencies were investigated by applying this enhanced compost to petroleum-contaminated soil under low temperatures. The results showed that the degrading bacteria can be enriched in the mature compost. After 30 d of remediation, the removal efficiency of TPH, alkanes, and PAHs in the soil was 27.0%, 19.6%, and 10.0%, compared to natural attenuation (CK), which was 4.5%, 9.5%, and 2.3%, respectively. In response to remediation, the relative abundance of Proteobacteria and Actinobacteria phyla decreased from 53.4% and 25.9% to 48.9% and 14.1%, respectively, and Bacteroidetes phylum increased from 5.0% to 24.5%. At the genus level, the relative abundance of Acinetobacter and Pseudomonas increased from 0.02% and 3.4% to 15.2% and 4.6%, respectively. The results indicated that the bioaugmented compost may efficiently facilitate and speed up the bioremediation of petroleum-contaminated soil under low-temperature conditions. Soil microbial diversity and structure of microbial communities are sensitive to the remediation.

Bacterial Community Diversity of Oil-Contaminated Soils Assessed by High Throughput Sequencing of 16S rRNA Genes.

Soil bacteria play a major role in ecological and biodegradable function processes in oil-contaminated soils. Here, we assessed the bacterial diversity and changes therein in oil-contaminated soils exposed to different periods of oil pollution using 454 pyrosequencing of 16S rRNA genes. No less than 24,953 valid reads and 6246 operational taxonomic units (OTUs) were obtained from all five studied samples. OTU richness was relatively higher in contaminated soils than clean samples. Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Planctomycetes and Proteobacteria were the dominant phyla among all the soil samples. The heatmap plot depicted the relative percentage of each bacterial family within each sample and clustered five samples into two groups. For the samples, bacteria in the soils varied at different periods of oil exposure. The oil pollution exerted strong selective pressure to propagate many potentially petroleum degrading bacteria. Redundancy analysis (RDA) indicated that organic matter was the highest determinant factor for explaining the variations in community compositions. This suggests that compared to clean soils, oil-polluted soils support more diverse bacterial communities and soil bacterial community shifts were mainly controlled by organic matter and exposure time. These results provide some useful information for bioremediation of petroleum contaminated soil in the future.

Establishing Correlations and Scale-Up Factor for Estimating the Petroleum Biodegradation Rate in Soil

ABSTRACTThe proper design of a bioremediation strategy for petroleum-contaminated sites requires a reasonable estimate of the biodegradation rate constant, which is not easy due to spatial heterogeneity. Accordingly, predictive models were developed by completing a bioventing study at the meso-scale. Reactors holding 4 kg of disturbed soil were tested using five different types of soils. Using statistical analysis, a two-stage process was observed, with a fast rate of hydrocarbon degradation in the first 8 days and a slower rate in the remaining 22 days. Review of the correlations showed that the initial population of petroleum-degrading bacteria and increasing silt content had a positive effect on the degradation. A negative impact on the degradation rate was seen by increasing the fraction of organic matter and clay content. Comparison of previously completed micro-scale and meso-scale degradation rates gave a scale-up factor (SF) of 1.8 ± 0.5. Soils with an increased sand fraction had slightly higher SF values, whereas soils high in organic matter content had lower SF values. The measured SF values and developed correlations will help practitioners with site closure decisions, indicating the need for additional SF work to allow better transfer of meso-scale data to the field.

The Removal Efficacy of Heavy Metals and Total Petroleum Hydrocarbons from Contaminated Soils by Integrated Bio-phytoremediation

ABSTRACT In this study, the bio-phytoremediation and phytoremediation technologies were applied to the soils contaminated withtotal petroleum hydrocarbons (TPH) and heavy metals to evaluate the remediation efficacy from May 2012 to December2013. Poplar (Populus bonatii Levl.) and Sun Hemp (Crotalaria juncea L.) were selected and planted in phytoremediationpractice. These plants were also utilized in the bio-phytoremediation practice, with the addition of earthworm (Eiseniafetida) and petroleum-degrading bacteria (Pseudomonos sp. NKNU01). Furthermore, physiological characteristics, such asphotosynthesis rate and maximal photochemical yield, of all testing plants were also measured in order to assess theirhealth conditions and tolerance levels in adverse environment. After 20 months of remedial practice, the results showedthat bio-phytoremediation practice had a higher rate of TPH removal efficacy at 30-60 cm depth soil than that ofphytoremediation. However, inconsistent results were discovered while analyzing the soil at 100 cm depth. The study alsoshowed that the removal efficiency of heavy metals was lower than that of TPH after remediation treatment. The resultsfrom test field tissue sample analysis revealed that more Zinc than Chromium was absorbed and accumulated by the testedplants. Plant height measurements of Poplar and Sun Hemp showed that there were insignificant differences of growthbetween the plants in remediation plots and those in the control plot. Physiological data of Poplar also suggested it hashigher tolerance level toward the contaminated soils. These results indicated that the two testing plants were healthy andsuitable for this remediation study.Keywrods: Total petroleum hydrocarbons (TPH), Bio-phytoremediation, Phytoremediation, Earthworm, Petroleum-degrading bacteria, Poplar, Sun Hemp

Temporal Changes in Microbial Metabolic Characteristics in Field-Scale Biopiles Composed of Aged Oil Sludge.

Disposal of oil sludge, a hazardous waste, is currently a prevalent environmental issue. In this study, two field-scale biopiles were constructed to explore the temporal changes of microbial metabolic characteristics during the biotreatment of aged oil sludge. Bulking agent was mixed thoroughly with oily sludge to form a treated pile. The BIOLOG™ system was used to analyze the community level physiological parameters, including microbial metabolic activity, diversity, and variance. In comparison with the control, the community level physiological parameters of the treated pile were dramatically improved. Microbial metabolic activity of the treated pile was improved by 25.06% calculated from the maximums during the treatment. Microbial diversity index (Shannon index) ranges were improved from 1.64-3.02 (control pile) to 2.34-3.14 (treated pile). The numbers of petroleum-degrading bacteria and the total heterotrophic bacteria were correlated with the environmental temperature, and microbial metabolic characteristics in the treated pile revealed the distinctive carbon resources selection with the addition of cotton stalk. Temporal microbial metabolic characteristics, which have important effect on bioremediation, were revealed in this study.

Study on the Impact Factors of Microbial Oil Displacement Efficiency

In order to quantify the microbial oil displacement efficiency, a group of petroleum-degrading bacteria were obtained from the sludge samples. Three strains of them with maximum degradation performance were tested to determine how the concentration of bacteria and nutrition affect the oil displacement efficiency. The volume of oil displaced by different strain was measured to find the rules of oil displacement efficiency change with time. From a practical point of view, the research found that there exist an optimum value between the oil displacement efficiency and concentration of bacteria and nutrient, which was related to crude oil price and cost of biological agents.

Response of microbial community to petroleum stress and phosphate dosage in sediments of Jiaozhou Bay, China

The dynamic microcosms were used to evaluate the effect of oil spills on microbial ecological system in marine sediment and the enhancement of nutrient on the oil removal. The function and structure of microbial community caused by the oil pollution and phosphate dosage were simultaneously monitored by dehydrogenase activity assay and PCR-denaturing gradient gel electrophoresis (DGGE) techniques. The results indicated that the amount of total bacteria in all dynamic microcosms declined rapidly with incubation time. The number of petroleum-degrading bacteria and the activity of sediment dehydrogenase were gradually enhanced by petroleum in the oil-treated microcosms, while they both showed no obvious response to phosphate dosage. In comparison, phosphate spiked heterotrophic bacteria and they showed a significant increase in amount. DGGE profiles indicated that petroleum dosage greatly changed community structure, and the bacteria belonged to class Deltaproteobacteria, and phyla Bacteroidetes and Chlorobi were enriched. This study demonstrated that petroleum input greatly impacted the microbial community structure and consequently the marine sediment petroleum-degrading activity was enhanced. Phosphate dosage would multiply heterotrophic bacteria but not significantly enhance the petroleum degradation.

Laboratory Research on Enhancing Oil Recovery of Three Bacteria D1-3

A group of petroleum-degrading bacteria were obtained from the sludge samples that collected from the Triassic Yanchang 6 reservoir. Of these, three strains with maximum degradation performance were tested in this study. The chromatographic analysis showed that the content of molecules with 30 or more carbons of oil was reduced by 18.36%. Core flood experiments with different flooding rate showed that the oil recovery of microbial flooding was increased by 8.76% than water flooding. The research ruled out that the three strains have well compatibility with the reservoir with remarkable result of petroleum-degrading.

English

In contaminated soils, the efficiency of natural attenuation or engineered bioremediation largely depends on the biodegradation capacities of the total microflorae. In the present study, the biodegradation capacities of various bacteria towards petroleum-hydrocarbons were determined under laboratory conditions. The purpose of the study was to isolate and characterize petroleum-degrading bacteria from contaminated soil obtained from a refinery in Arzew, Algeria. A collection of 15 bacterial isolates were obtained by enrichment cultivation from oil-contaminated soil and an indigenous microbial consortium was developed by assembling four species of bacteria which could degrade different fractions of the petroleum hydrocarbons. 16S rRNA gene analysis was used to identify members of the consortium and oil biodegra- dability was analyzed by Thin Layer Chromatography (TLC) with Flame Ionization Detection (FID) that performs quantitative compositional analysis of oil samples. The Iatroscan TLC/FID system measured the relative percentages of the four major fractions of petroleum i.e. satu- rates aromatics, resins and asphaltenes. Results indicated that the constructed consortium which comprised the genera Pseudomonas, She- wanella, Enterobacter and Serratia used the hydrocarbons as sole sources of carbon where biodegradation was defined by an initial rapid decrease in the saturate and aromatic fractions from 56.44% and 34.72% to 51.77% and 27.77% respectively, coinciding with an increase in the asphaltene fraction. The resin content remained relatively constant throughout the project. Alkane hydroxylase genes (alkB) were positively amplified in the Pseudomonas isolate by the polymerase chain reaction (PCR) method using degenerate primers. This functional gene was used as a marker to assess the catabolic potential of the bacteria for alkane pollutant biodegra- dation. The selected bacterial consortium looks promising for its application in bioremediation technologies.

Transcriptional response of bathypelagic marine bacterioplankton to the Deepwater Horizon oil spill

The Deepwater Horizon blowout released a massive amount of oil and gas into the deep ocean between April and July 2010, stimulating microbial blooms of petroleum-degrading bacteria. To understand the metabolic response of marine microorganisms, we sequenced ≈ 66 million community transcripts that revealed the identity of metabolically active microbes and their roles in petroleum consumption. Reads were assigned to reference genes from ≈ 2700 bacterial and archaeal taxa, but most assignments (39%) were to just six genomes representing predominantly methane- and petroleum-degrading Gammaproteobacteria. Specific pathways for the degradation of alkanes, aromatic compounds and methane emerged from the metatranscriptomes, with some transcripts assigned to methane monooxygenases representing highly divergent homologs that may degrade either methane or short alkanes. The microbial community in the plume was less taxonomically and functionally diverse than the unexposed community below the plume; this was due primarily to decreased species evenness resulting from Gammaproteobacteria blooms. Surprisingly, a number of taxa (related to SAR11, Nitrosopumilus and Bacteroides, among others) contributed equal numbers of transcripts per liter in both the unexposed and plume samples, suggesting that some groups were unaffected by the petroleum inputs and blooms of degrader taxa, and may be important for re-establishing the pre-spill microbial community structure.

토양 경작법을 이용한 유류오염토양 정화사업 타당성 연구

ABSTRACT The landfarming treatment for the remediation of the petroleum contaminated soil at the returned U.S. Military bases wasinvestigated in this study. Specifically, the bioaugmentation performance using various commercially available petroleum-degrading bacteria was evaluated and the directions for enhancing the performance of the landfarming treatment weresuggested. The environmental factors of the soils at the returned U.S. Military bases chosen for remediation indicate thatthe landfarming treatment can be used as the remediation technique; however, the addition of nitrogen or phosphorus isrequired. The lab-scale landfarming treatment tests using the model soil and the site soil showed that the degradationefficiency was greater with the model soil than the site soil and that the treatment performance was not affected by thenumber of bacteria present in the soil in the range of 10 6 -10 12 CFU/g. These results suggest that the successful landfarmingtreatment depends on the petroleum degradability of bacteria used and the environmental conditions during the treatmentrather than the number of petroleum-degrading bacteria used. Key words: Landfarming, Petroleum-contaminated soil, Soil remediation, Petroleum-degrading bacteria, Contaminantaging

Multi-process Bioremediation as an Improved Approach for Petroleum-contaminated Soil Restoration

A multiprocess bioremediation approach was applied to treat petroleum-contaminated soil from Dagang Oilfield, China. The bioremediation processes involved the use of four exogenous microbial strains and six herbage plants screened from a large number of species to remove low levels of total petroleum hydrocarbons (TPH) in contaminated soil. The experimental results indicated that the reduction of TPH increased with the improved community structure from the exogenous petroleum-degrading bacteria by over 35% as compared with that using the indigenous bacterial community. The refreshed microbial consortium was also able to accelerate the reduction of TPH via plant roots (phytoremediation) by over 47%. The TPH reduction rate diminished over time. Molecular biomarker ratios such as Ph/nC17, Pr/nC18 increased during the experiment but the ratio of Pr/Ph decreased. The results suggested that the multi-process bioremediation may significantly shorten the bioremediation duration and can be quite effective for treatment of soils contaminated by lower levels of petroleum.

Determination of petroleum-degrading bacteria isolated from crude oil-contaminated soil in Turkey

In order to establish an experimental basis for bioremediation of soil contaminated with crude oil, 33 strains of bacteria with hydrocarbon-degrading ability were isolated from the contaminated soil in Adana, Batman and Adiyaman, Turkey. The strains were identified as Pseudomons spp., Paucimonas lemoignei, Stenotrophomonas maltophilia, Eschericha spp., Enterobacter spp. Citrobacter koseri, Acinetobacter spp., Aeromonas caviae, Sphingobacterium multivorum, Klebsiella pneumoniae. Pseudomons aeruginosa, Pseudomonas putida biotype A, Citrobacter amalonaticus GC subgroup A and Acinetobacter genomospecies, respectively. The ability to utilize crude oil as carbon source for their growth was ascertained. These bacterial isolates obtained in this study have catabolic capabilities for the biodegradation of petroleum hydrocarbons. Further study under soil conditions may be necessary to determine biodegradation potential of bacterial mixture tested in contaminated soil. Key words : Soil, crude oil, soil pollution, bacteria, biodegradation.

Mineralization of Petroleum Contaminated Wastewater by Co-Culture of Petroleum-Degrading Bacterial Community and Biosurfactant-Producing Bacterium

Activity of a crude biosurfactant extracted from the culture fluid of Serratia sp. that was isolated from riverbed soil was shown to increase in proportion to the cultivation time, and was higher at pH 8 than at pH 7. Serratia sp. grew in the mineral-based medium with soybean oil but was not with kerosene-diesel. The petroleum-degrading bacteria—Acinetobacter sp., Pseudomonas sp., Paracoccus sp., and Cupriavidus sp.—were isolated from a specially designed enrichment culture. The efficiency of mineralization of wastewater contaminated with kerosene and diesel (WKD) by the petroleum-degrading bacterial community (PDBC) was enhanced significantly by addition of the crude biosurfactant. The efficiency of mineralization of the WKD was also about 2 times boosted by co-culture of Serratia sp. and PDBC. Bacterial community of Serratia sp. and PDBC co-cultivated in the WKD was maintained for at least 8 days according to the TGGE pattern of 16S rDNA obtained from the bacterial culture. In conclusion, the co-culture of Serratia sp. and PDBC is an applicable technique for the mineralization of wastewater contaminated with petroleum, which may substitute for chemical or biological surfactant.

Characterization and biotechnological potential of petroleum-degrading bacteria isolated from oil-contaminated soils

A collection of 38 bacteria was obtained by enrichment cultivation from oil-contaminated soils of an oil field in Daqing, China. Twenty-two strains could utilize diesel oil as the sole source of carbon and energy, and 11 strains could degrade the total petroleum hydrocarbons (TPHs) of diesel oil by more than 70% in 7 d. Phylogenetically, 19 of the bacteria related to Bacillus species. About 87.5% TPHs of crude oil were degraded by a consortium of seven strains. Denaturing gradient gel electrophoresis analysis suggested that five of the strains persisted throughout the degradation process. The collection of isolated bacteria might be a useful resource for bioremediation of oil-contaminated soils and biotreatment of oil wastewater.

Compound-Specific Stable Carbon Isotope Analysis of MTBE in Groundwater Contamination Fingerprinting Studies: The Use of Hydrogeologic Principles to Assess Its Validity

Methyl-tert-butyl ether (MTBE) is an oxygenate added to gasoline in the United States and elsewhere to boost the octane ratio and reduce tailpipe emissions. Because of its known usage time frame, the presence of MTBE can help estimate the age of gasoline releases to the environment. However, because of its ubiquity, its presence can no longer be used to fingerprint, or differentiate, gasoline plumes in groundwater. Compound-specific stable carbon isotope analysis has recently become a method for differentiating MTBE sources and plumes affecting groundwater. In the present study, groundwater samples were collected from 20 monitoring wells located at two gasoline service stations in central New Jersey in an attempt to differentiate the dissolved gasoline plumes and possibly identify their sources. The carbon isotope ratio (13C/12C expressed as δ13C) values for each sample were determined through gas chromatography–isotope ratio–mass spectrometry (GCIRMS), and the impacted area for each plume was delineated. As biological degradation of MTBE proceeds, δ13C becomes heavier; petroleum-degrading bacteria preferentially assimilate the lighter 12C isotope, thereby enriching the residual MTBE in the heavier 13C isotope. The isotopic composition of MTBE at different locations demonstrated the varying degree to which MTBE had been altered by biodegradation. The δ13C values can also provide insight into the type of release and the magnitude of biodegradation. Two types of leaks occurred at the sites: a shallow piping leak and deeper leak from a tank system. δ13C values in the vicinity of the shallow leak were heavier, revealing increased biodegradation in the soil, while δ13C values in the vicinity of the tank leak were lighter, revealing the lack of biological degradation in non-aqueous phase liquid (NAPL) trapped beneath the water table. An assessment is provided where the physical site characteristics responsible for petroleum weathering are considered in comparison with the measured δ13C values.

Escravos light crude oil degrading potentials of axenic and mixed bacterial cultures

We assessed the relationship between growth profile and the extent of biodegradation of Escravos light crude oil by axenic and mixed bacteria cultures in a shake flask. Eleven petroleum-degrading bacteria were isolated by enrichment from oil-contaminated soils including, Pseudomonas effusa, Pseudomonas fluorescens, Pseudomonas cruciviae, Arthrobacter tumescens, Pseudomonas species, Pseudomonas tralucida, Alcaligenes metacaligenes, Micrococcus colpogenes, Bacillus badius, Nocardia paraffinae and Bacillus species. Specific growth rates of axenic cultures of the bacteria during degradation of Escravos light crude oil ranged between 0.0037 and 0.0505 h(-1), while that of the mixed cultures varied from 0.0144 to 0.1301 h(-1). The crude oil was biodegraded by between 28.71% and 99.01% for single cultures and between 12.38% and 91.58% for the mixed cultures. Although specific growth rate and biomass were important at the initial stages of biodegradation, there was no significant correlation between growth rate and biomass and the extent of biodegradation of Escravos light crude oil.