Bioremediation Of Crude Oil Research Articles

Bacterial Communities Associated with Crude Oil Bioremediation through Composting Approaches with Indigenous Bacterial Isolate.

In this study, we aim to investigate the efficiency of crude oil bioremediation through composting and culture-assisted composting. First, forty-eight bacteria were isolated from a crude oil-contaminated soil, and the isolate with the highest crude oil degradation activity, identified as Pseudomonas aeruginosa, was selected. The bioremediation was then investigated and compared between crude oil-contaminated soil (S), the contaminated soil composted with fruit-based waste (SW), and the contaminated soil composted with the same waste with the addition of the selected bacterium (SWB). Both compost-based methods showed high efficiencies of crude oil bioremediation (78.1% and 83.84% for SW and SWB, respectively). However, only a slight difference between the treatments without and with the addition of P. aeruginosa was observed. To make a clear understanding of this point, bacterial communities throughout the 4-week bioremediation period were analyzed. It was found that the community dynamics between both composted treatments were similar, which corresponds with their similar bioremediation efficiencies. Interestingly, Pseudomonas disappeared from the system after one week, which suggests that this genus was not the key degrader or only involved in the early stage of the process. Altogether, our results elaborate that fruit-based composting is an effective approach for crude oil bioremediation.

Biodegradation kinetics of binary mixture of hexadecane and phenanthrene by the bacterial microconsortium

Crude oil bioremediation requires a correct selection of potential biodegraders to address the hazard. The present study investigates biodegradation kinetics of single aliphatic (Hexadecane, HEX), aromatic (Phenanthrene, PHE), and binary mixture (HEX + PHE) as co-contaminants by axenic cultures of A. fabrum SLAJ 731, B. subtilis RSL2 and P. aeruginosa P7815 and their consortium. A proposed integrated kinetic model combining first-order exponential decay and the Monod equation is well-fitted to degradation data. Maximum degradations of both the substrates were observed for microcosm, indicating synergistic effects of selected strains. The degradation rate indicated parallel utilization of HEX while serial utilization of PHE by selected strains. Maximum HEX and PHE degradations of 92.4 and 88.7 % were achieved by microconsortium, which increased to 97.2 and 91.9 % for the binary mixture. The biodegradation efficiencies of HEX and PHE were linearly correlated with Alkane hydroxylase and Catechol-2,3-dioxygenase activities, respectively.

Kinetic modeling and half-life study on bioremediation of crude oil dispersed by palm bunch enhanced stimulant

The work focused on the kinetic modeling and half-life study of the bioremediation of crude oil dispersed by palm bunch enhanced stimulant. In this study, three bioremediation processes, namely; palm bunch enhanced stimulant (PES) stimulation, modified crude oil dispersant (MCD) stimulation and natural attenuated stimulation (NAS), were carried out at various petroleum hydrocarbon concentrations in polluted water media. Bacterial culture, isolations, and identification were carried out to isolate and identify the bacterial involved in the bioremediation. The process kinetics and half-life were investigated. Characterization of PES showed that PES has an appreciable quantity of potassium, phosphate, nitrate, sulphate and calcium required for cell growth and development. Bacillus pumilus, Micrococcus roseus, Micrococcus luteus, and Pseudomonas putida were the bacteria isolated from the culture. The optimum bio-stimulation efficiency of PES occurred on day 6, with BE values of 93.23%. The degradation rate constants for the PES enhanced bioremediation process decreased as the crude oil initial concentration increased from 100 to 300 mg/L. The result showed that the degradation rate constants for PES stimulated remediation were 0.11, 0.04 and 0.03 at 100, 200 and 300 mg/L of crude oil, respectively. The MCD stimulated remediation showed degradation rate constants of 0.04, 0.03 and 0.018, at crude oil concentrations of 100, 200, and 300 mg/L, respectively. The trend was the same for NAS. The longest half-life for 100 mg/L of crude oil was achieved after 79.67 days during the NAS stimulation. The results obtained from this report showed tremendous improvement to the degradation of crude oil due to the presence of PES. The degradation process was adequately described by the first order kinetic model and showed the effectiveness of PES in the remediation process. Therefore, the data obtained in this study could be applied in the design of a bioremediation system for potential application to remediation of crude oil polluted water.

Application of Agro-Waste in Bioremediation of Crude Oil Polluted Soil from Agip Oil Spill Sites at Abecheke Ohaji-Egbema Local Government Area of IMO State

Application of Agro-Waste in Bioremediation of Crude Oil Polluted Soil from Agip Oil Spill Sites at Abecheke Ohaji-Egbema Local Government Area of IMO State

Biodegradation of crude oil by a moderately haloalkaliphilic Acinetobacter strain

Bioremediation of crude oil (or petroleum) pollution in the saline-alkali environment is challenging due to the lack of halotolerant and alkali tolerant oil-degrading bacteria. It is shown here that a newly isolated Acinetobacter strain D2 able to degrade crude oil was moderately haloalkaliphilic. Physiological characterization showed that the optimal crude oil degradation conditions for D2 strain occurred at pH = 9 and NaCl concentration of 2% w/v. Moreover, D2 can tolerate pH 11 and NaCl concentration of 8% w/v. Kinetic analysis indicated that crude oil (0.2% and 0.5% w/v) biodegradation by D2 followed the first-order kinetic model, with the k constant estimated as 0.089–0.111 d−1 and the half-life period of petroleum degradation as 6.24–7.79 d. The results of the gas chromatographic analysis revealed that strain D2 could degrade most saturated hydrocarbons, with higher removal efficiencies for shorter-chain alkanes. Strain D2 can also remove aromatic hydrocarbons with an average efficiency of 33.4%. Combined, these results demonstrated that a moderately haloalkaliphilic Acinetobacter strain can be a suitable candidate for bioremediation of oil-contaminated saline soil and oilfield produced water.

Characterization of Efficient Biosufactants Producing Bacteria and its Efficacy on Bioremediation of Crude Oil

The present work was aimed to isolate efficient hydrocarbon degrading and biosurfactant producing bacteria strain from oil contaminated site. Biosurfactant are low molecular surface active compounds involved in the degradation of hydrocarbons. Biosurfactant activity of isolated strain were detected by using different screening method. The study showed that efficient biosurfactant producing bacteria were identified as Arthrobacter globiformis. More over, crude oil degradation as consortium degraded more effectively than individual strain.

Low-cost production and application of lipopeptide for bioremediation and plant growth by Bacillus subtilis SNW3

At present time, every nation is absolutely concern about increasing agricultural production and bioremediation of petroleum-contaminated soil. Hence, with this intention in the current study potent natural surfactants characterized as lipopeptides were evaluated for low-cost production by Bacillus subtilis SNW3, previously isolated from the Fimkessar oil field, Chakwal Pakistan. The significant results were obtained by using substrates in combination (white beans powder (6% w/v) + waste frying oil (1.5% w/v) and (0.1% w/v) urea) with lipopeptides yield of about 1.17 g/L contributing 99% reduction in cost required for medium preparation. To the best of our knowledge, no single report is presently describing lipopeptide production by Bacillus subtilis using white beans powder as a culture medium. Additionally, produced lipopeptides display great physicochemical properties of surface tension reduction value (SFT = 28.8 mN/m), significant oil displacement activity (ODA = 4.9 cm), excessive emulsification ability (E24 = 69.8%), and attains critical micelle concentration (CMC) value at 0.58 mg/mL. Furthermore, biosurfactants produced exhibit excellent stability over an extensive range of pH (1–11), salinity (1–8%), temperature (20–121°C), and even after autoclaving. Subsequently, produced lipopeptides are proved suitable for bioremediation of crude oil (86%) and as potent plant growth-promoting agent that significantly (P < 0.05) increase seed germination and plant growth promotion of chili pepper, lettuce, tomato, and pea maximum at a concentration of (0.7 g/100 mL), showed as a potential agent for agriculture and bioremediation processes by lowering economic and environmental stress.Graphical

Effect of Aerating Duration on Hydrocarbon Biodegradation in a Simulated Crude-Oil Polluted Aquatic Environment Undergoing Bioremediation

The aim of this research work was to determine the aerating duration that would be effective in enhancing hydrocarbon biodegradation rate during bioremediation of crude-oil polluted river. Sediment and river-water were placed in four glass troughs labeled CT (control), A, B, and C. The setups were polluted with crude-oil, and allowed undisturbed for 2 weeks. Subsequently, accessible crude-oil on the surface was removed; bacteria and nutrients were then added. Air was bubbled for 3 hours into setups A, B, and C, at daily, 3 days, and 7 days interval respectively. Aeration was not applied to setup CT. On day 1, 7, 14, and 21, hydrocarbon concentration was determined; populations of total heterotrophic bacteria (THB) and hydrocarbon-utilizing bacteria (HUB) were also determined. The time it will take for hydrocarbons in the setups to biodegraded “completely” was calculated using first-order reaction equation. The results obtained showed that 71.43, 86.39, 83.17, and 15.42 % hydrocarbon degradation were obtained in setup A, B, C, and CT respectively. The time it will take for hydrocarbons in the setups to biodegrade “completely” were 129, 89, 101, and 1079 days for A, B, C, and CT respectively. There was slight reduction in population of HUB in setup CT, fairly stable population in setup A, and increase in population of HUB in setups B and C. It is concluded that aerating crude-oil polluted aquatic environment for 3 hours at 3 days interval will be more effective in enhancing hydrocarbon biodegradation rate during bioremediation.

The physico-chemical characteristics of fresh and old pig dungs collected from three pig farmsin Port Harcourt Metropolis

The need to source for alternative use of pigs dung to reduce environmental challenges arising from its application as farm manure prompted the study into the physico-chemical attributes of both the fresh and old pig dung in three pig farms(A,R,U) in Port-Harcourt metropolis. The study examined the pH levels, exchangeable nitrate, extractable phosphate, the total organic carbon and the sulphate using methods described by the pH meter, APHA-4500-O3-B, ASTM D515, Walkley black and ASTM D516 respectively. The results indicated that the dung were alkaline ranging from pH 9-12, the nitrate content was high in fresh dung (16.03-19.40) but considerably low in the dry dung (2.36-2.92), the phosphate values were between 7.59-20.81, the sulphate level falls within 1.84-3.79 whereas the total organic carbon were between 2.36-2.92. The result obtained have showed that the fresh dung could be supplemented with other organic substrate to initiate bioremediation of crude oil polluted soil due to its high nitrate content and the dry dung used as feedstuffs for animal nutrients or feedstock for bioenergy generation because of its high fibre content which will help in reducing the ecosystem contamination by pig waste through recycling.

Pig (Sus scrofa domesticus) dung and their associated fungi: Potential candidates for bio-remediation and nutrients improvement of crude oil contaminated soils

Abstract. Enyiukwu DN, Bassey IN, Nwaogu GA, Asamudo NU, Chukwu LA, Monday EA, Maranzu JO. 2021. Pig (Sus scrofa domesticus) dung and their associated fungi: Potential candidates for bio-remediation and nutrients improvement of crude oil contaminated soils. Biodiversitas 22: 3276-3286. Pig dung a common agro-waste material in Nigeria is associated with many fungal saprophytes. Rising oil spillages and pollution in Nigeria have made cultivation of affected agro-lands un-rewarding. Potentials of pig dung in mitigating crude oil pollution in agro-soils are herein studied. The objectives of this study were to characterize the fungal profile associated with wet and dry dung of pig. And to evaluate the remediating impacts of pig dung and their associated fungi on crude oil and heavy metals contents, physicochemical properties, and phytotoxicity of crude oil polluted soils. Coprophilous fungi were isolated from wet and dry dung by moist chamber technique and identified. Utisoil from Umudike was polluted with crude oil, amended with 10-40% of dry pig dung and sown with soybean (Glycine max L.). The amended and un-amended crude oil contaminated utisols were analyzed to reduce crude oil and heavy metals contents; and physicochemical properties at planting, and harvesting, respectively, using classical and spectrometric methods, and the extent of crude oil and heavy metals removal determined. The percentage germination, height, number of leaves, leaf color, vigor, and biomass of the test crop were recorded from the test plant. The results showed that Aspergillus candidus, Sclerotium sp., Absidia sp., Acremonium sp., Candida tropicalis, C. pseudotropicalis, and Rhizopus oryzae were consistently isolated from the dry dung specimen than the wet one. The results also indicated that the treatments significantly reduced the treated soils' crude oil and heavy metals contents. It revealed that values obtained for residual oil or heavy metals contents of the treated soils and crop performance were inversely and directly related to levels of soil amendment respectively. Crop performance in the amended soil remained statistically (P?0.05) higher compared to the control. Soil analyses showed that the dung treatments significantly increased the values of nitrogen, phosphorus, potassium, organic carbon, etc. in a directly proportional manner. Therefore, pig dung and their associated fungi hold strong potentials as cheap eco-friendly platforms to provide and stimulate microbial growth, hasten degradation and removal of crude oil and heavy metals from contaminated soils; and thus permit and sustain good performance of arable crops.

Compositional Characterization of Biosurfactant Produced from Pseudomonas aeruginosa ENO14-MH271625 and its Application in Crude Oil Bioremediation

Objectives: This study aimed to compositionally characterize the biosurfactant and its application in crude oil bioremediation. Methods: Production of biosurfactant was carried out in Bushnell Hass Broth (BHB), supplemented with 1% glucose. Compositional characterizations were performed by 1H-NMR and ESI-MS analysis. The biodegradation of crude oil was carried out by using a 0.1% (g/v) of purified biosurfactant (ENO14BS). The experiment has three sets namely Set A, Set B and Set C. The experiments are as follows: Set A contained 50 ml sterilized BHB medium with bacterial cells (5% v/v, O.D.600 ~ 1.0), 2% (v/v) of crude oil and ENO14BS (0.1 % w/v). Set B contained 50 ml of sterilized BHB medium with bacterial cells (5% v/v, O.D.600 nm ~ 1.0) and 2% (v/v) of crude oil. Set C (abiotic control) contained 50 ml of sterilized BHB with 2% (v/v) of crude oil only. This experiment was performed for 7 days. Results: Structural elucidation by NMR and Electrospray Ionization-Mass Spectroscopy (ESIMS) showed the presence of six uncommon rhamnolipid homologs, m/z (mass to charge ratio) = 358.98 [M+H]+, Rha-C12:2; m/z = 391.28 [M+H]+, Rha–C6–C6; m/z = 427.38 [M+H]+, Rha–C17:3; m/z = 447.32 [M+H]+, Rha–C8- C8; m/z = 507.22 [M+H]+, Rha-Rha-C12:1; m/z = 648.17 [M+H]+, Rha-Rha- C10-C10:1. The application of biosurfactant (ENO14BS) in biodegradation of crude oil was performed at a laboratory scale. The biosurfactant (0.1% w/v) amended microcosm showed up to 73% crude oil degradation (31% higher than with culture alone) in four days. Conclusion: We conclude that ENO14BS biosurfactant produced by Pseudomonas aeruginosa ENO14 using glucose in this study has shown its potential for use in the crude oil bioremediation process.

Synergistic adsorption and biodegradation of heavy crude oil by a novel hybrid matrix containing immobilized Bacillus licheniformis: Aqueous phase and soil bioremediation

Recently, slurry phase bioremediation as a simple and economical method is shown to be a successful technique for remediation of clayey soils. Besides, the use of microbial cell immobilization as a promising technique has drawn the attention of some researchers. The primary objective of this survey is to examine the synergistic adsorption and biodegradation performance of heavy crude oil by an isolated Bacillus licheniformis immobilized in a novel hybrid matrix (PUF/alginate/microbial cell) in aqueous phase. Isotherm studies and adsorption kinetics of crude oil on PUF matrix were carried out and their results revealed a good correlation between experimental data and Langmuir’s isotherm and maximum monolayer coverage was found out to be 1.25 g/g PUF. The other objective of this research is examination of hybrid matrix in slurry phase bioremediation of heavy crude oil polluted clayey soil as a reluctant model soil. In order to model, optimize, and investigate the factors affecting the total organic carbon (TOC) reduction, response surface methodology (RSM) was applied. For this purpose, the effect of three variables including crude oil concentration (5000–25,000 mg/kg dry soil), soil salinity (0–10%), and water to soil ratio (WSR: 2–10) have been studied. In this study, TOC reduction was achieved in ranging from 39% to 80% in crude oil polluted soil after 21 days. Additionally, experiments by polyurethane foam (PUF)-immobilized cell, alginate-immobilized cell, and freely cell suspended systems were conducted to compare the performance of hybrid-immobilized cell with other systems. Our results showed the superiority of immobilized cells in hybrid matrix of PUF/alginate compared to other immobilized cell (IC) and free cell (FC) systems. Overall, the results indicated that the hybrid matrix with simultaneous adsorption-biodegradation capacity is potentially suitable for further development for oil spill treatment and it can be used as an efficient cleaning method in TOC removal from actual polluted soils.

Extra-Heavy Crude Oil Degradation by Alternaria sp. Isolated from Deep-Sea Sediments of the Gulf of Mexico

The Gulf of Mexico (GoM) is an important source of oil for the United States and Mexico. There has been growing interest, particularly after the Deepwater Horizon oil spill, in characterizing the fungal diversity of the GoM and identifying isolates for use in the bioremediation of petroleum in the event of another spill. Most studies have focused on light crude oil bioremediation processes, while heavy crude oil (HCO) and extra-heavy crude oil (EHCO) have been largely ignored. In this work, we evaluated the ability of fungal isolates obtained from deep-sea sediments of the Mexican economic exclusive zone (EEZ) of the GoM to degrade HCO (16–20° API) and EHCO (7–10° API). Alternaria sp., Penicillium spp., and Stemphylium sp. grew with HCO as the sole carbon source. Remarkably, Alternaria sp. was the only isolate able to grow with EHCO as the sole carbon source, degrading up to 25.6% of the total EHCO and 91.3% of the aromatic fraction, as demonstrated by gas chromatography analysis of the saturate, aromatic, and polar fractions. These findings proved to be significant, identifying Alternaria sp. as one of the few fungi reported so far capable of degrading untreated EHCO and as a suitable candidate for bioremediation of EHCO in future studies.

Crude oil and pyrene degradation by halotolerant fungi Embellisia sp. KJ59 and Alternaria sp. KJ66 isolated from saline soils

ABSTRACT In recent years, investigating halophilic and halotolerant fungi enzymes has confirmed their significant potential in the biodegradation of crude oil. The aim of the current study was to evaluate the biodegradation of crude oil by halotolerant fungal Embellisia sp. KJ59 and Alternaria sp. KJ66. The fungal strains were isolated on Czapek Dox Agar (CDA), potato dextrose agar (PDA), and malt extract agar (MEA) containing 10% NaCl. Seven strains that could grow in salinity, ranging from 0 to 17% were selected. Out of the seven isolates, isolates KJ59 and KJ66 were selected as superior strains because they were more efficient in the biodegradation of crude oil on Minimal Salt Medium containing 1% crude oil and different salinity. The isolates were identified as Embellisia sp. and Alternaria sp. based on its nucleotide sequence of internal transcribed spacer gene. They could biodegrade petroleum, ranging from 81.3 to 95.1% in NaCl concentrations of 0, 2.5, and 5% on PDB over a period of 14 days. Pyrene removal by these strains was over 88.3% in saline and non-saline MSM containing 100 mg L−1 pyrene. Finally, Embellisia sp. KJ59 and Alternaria KJ66 were introduced fungal strains for crude oil biodegradation as the sole or supplementary carbon source in the presence of different salt concentrations. Furthermore, they are potential fungal strains for bioremediation of crude oil in non-saline and contaminated saline environments.

Biotreatment of oil sludge containing hydrocarbons by Proteus mirabilis SB

The release of petroleum hydrocarbons in the form of oil sludge poses a serious threat to people and the environment. At present, biodegradation of oily sludge is regarded as one of the most promising harmless treatment technologies, where the screening of high efficient degrading strains is the key to its implementation. In the present study, a strain Proteus mirabilis SB was isolated from oil sludge of Jingbian Oil Field. The strain grew and reproduced rapidly with petroleum hydrocarbon as the sole carbon source in the optimal growth temperature range of 30–35 °C, and salinity less than 6%. Its effective emulsification function was attributed to the production of biosurfactants, mainly rhamnolipids, through metabolism. Analysized by gas chromatography (GC) and four-fraction the degradation efficiency of total petroleum hydrocarbon (TPH) reached 70.5% within 2 weeks in the liquid culture medium, while the degradation efficiencies of saturated hydrocarbons, aromatics, resins and asphaltenes were 90.8%, 69.2%, 16.3% and 31.5%, respectively. For degrading petroleum hydrocarbons in oil sludge within a quasi-solid culture system under standard atmospheric conditions, a total degradation efficiency of 76.9% over 60 days was obtained, while 90.8% of saturated hydrocarbons and 69.2% of aromatics were degraded. Overall, the strain was capable of degrading petroleum hydrocarbons in both crude oil and oil sludge with high efficiencies This development demonstrated strong potential of Proteus mirabilis SB for oil sludge treatment and in situ bioremediation of crude oil contaminated soil/land.

Bio-remediation of crude oil contaminated soil using recombinant native microbial strain

The manufacture, carriage, refining, and storage of crude oil are several surface and subsurface soil pollution sources. In crude oil handling operations, there is a significant number of polluted sites worldwide. This research was performed on trays with particular prominence in the biodegradation of n-alkanes to biodegrade artificially produced oil-polluted soil by microorganic strains. Two native isolates from five isolates were selected for preliminary oil degradation potential study. Previously microbial strains are isolated from crude oil contaminated soil collected from nearby oil well areas in Thiruvarur district, Tamil Nadu state, India. One promising isolate among the two microbial strains is selected for recombinant progression after completing the recombinant process. The wild and recombinant microbial strain was inoculated in the soil at ambient conditions for 42 days with different oil concentrations of 0.5%, 1%., 3%, and 5%. The total petroleum hydrocarbon (TPH) analysis has been quantitatively tracked. The biodegradation process is monitored by a gas chromatographic–mass spectrometer (GC–MS) analysis. Following 42 days of incubation, the findings showed a higher TPH biodegradation performance of the recombinant microbial strain than that of the wild microbial strain. The recombinant microbial strain showed total normal alkanes degradation significantly. This work will untie a new corridor of bioremediation of crude oil contaminated soil using recombinant microbial strain. • A detailed study on oil contamination caused by the spillage in oil drilling stations in Cauvery delta region. • Bio-remediation and microbial and molecular techniques have been discussed thoroughly. • Pseudomonas guguanensis bacteria were isolated in Indian hydrocarbon contaminated soil. • Biodegradation and evaluation of hydrocarbon in contaminated soil are experimentally studied. • Recombinant strain biodegradation potential is high compared to native microorganisms.

Application of nitrogen fixing bacteria and poultry droppings for enhanced bioremediation of crude oil polluted-soil

The exploration, production and refining of crude oil has led to severe environmental degradation in the oil producing communities of the Niger Delta region of Nigeria. Enhanced bioremediation of tropical rainforest soil artificially polluted with crude oil, bioaugmented with nitrogen fixing bacteria (NFB) and biostimulated with poultry droppings was carried out ex situ. Soil sample was collected at 15cm depth from tropical rainforest soil of the University of Port Harcourt, Nigeria. The NFB was isolated from roots of leguminous plant Arachis hypogea, identified as Nitrobacter species. Bioaugmentation by application of NFB served as option A, option B (biostimulation by application of poultry droppings), option C (No amendment) served as the control. Bioremediation was monitored for 28 days for interval of 14 days, and determined using the percentage ratio of total petroleum hydrocarbon (TPH) losses for each period to TPH at initial day (day zero). Results of total culturable heterotrophic bacterial (TCHB) counts showed that highest range in option B (1.9×104- 2.4×109Cfu/g) than in option A (7.8×106 -2.29×107Cfu/g) and C (6.75×106 -2.6×107Cfu/g) respectively. Similarly, hydrocarbon utilizing bacterial (HUB) counts had higher range in option B (1.20×105 - 1.9×107Cfu/g) than in option A (8.30×104 - 2.30×105Cfu/g) and option C control (4.3×104 −1.69×105 Cfu/g) respectively. Changes in physicochemical parameters during the study showed reductions in nitrate, phosphate and TPH in all the options expect pH which showed slight increase in option C (6.20-6.24). Characterization and identification for bacteria revealed the following HUB genera Pseudomonas, Citrobacter, Bacillus, Corynebacterium, Micrococcus, Klebsiella, Staphylocuccus and Nitrobacter). The percentage losses in TPH from gas chromatography (GC) results showed the following; option A (44.24%) option B (61.08%) and option C - control (27.28%) respectively. The results from this study showed that option B, the application of poultry droppings as biostimulant was more efficient than the application of NFB in enhanced bioremediation of crude oil polluted soil, hence the use of poultry droppings which is available as organic waste, eco-friendly and cost-effective is recommended asbiostimulant for enhanced bioremediation in environmental cleanup of crude oil impacted-sites of the Niger Delta region of Nigeria.&#x0D; Key Words: Bioremediation, Crude oil polluted-soil, Biostimulation, Bioaugumentation, Poultry droppings, Nitrogen fixing bacteria.

Isolation and Characterization of Oil-Degrading Enterobacter sp. from Naturally Hydrocarbon-Contaminated Soils and Their Potential Use against the Bioremediation of Crude Oil

The contamination of crude oil in soil matrices is a persistent problem with negative repercussions because of the recalcitrant, hazardous, and mutagenic properties of its constituents. To mitigate the effect of crude oil contamination in soil, the use of microorganisms is a cheap and feasible option. In the current study, bacterial species from numerous polluted oil field surfaces were isolated and examined for their ability to degrade crude oil. Random soil samples polluted with hydrocarbons were collected and various bacterial isolates were isolated. Results revealed that 40% of total isolates had potential use for hydrocarbon biodegradation, the synthesis of exopolysaccharides and the solubilization of phosphorous. Following isolation and characterization to degrade crude oil, a pot trial was conducted using maize inoculated with the four best strains—i.e., S1 (PMEL-63), S2 (PMEL-67), S3 (PMEL-80), and S4 (PMEL-79)—in artificially hydrocarbon-polluted soil with concentrations of crude oil of 0, 1000, and 2000 ppm. Results revealed that S4 (PMEL-79) had significant potential to degrade hydrocarbon in polluted soils. The root length, shoot length, and fresh biomass of maize were increased by 65%, 45%, and 98%, respectively, in pots inoculated with S4 (PMEL-79) Enterobacter cloacae subsp., whereas the lowest root length was observed where no strain was added and the concentration of crude oil was at maximum. Moreover, S4 (PMEL-79) Enterobacter cloacae subsp. was found to be the most effective strain in degrading crude oil and increasing maize growth under polluted soil conditions. It was concluded that the isolation of microorganisms from oil-contaminated sites should be considered in order to identify the most effective microbial consortium for the biodegradation of naturally hydrocarbon-contaminated soils.

Prokaryotic community diversity during bioremediation of crude oil contaminated oilfield soil: effects of hydrocarbon concentration and salinity.

Crude oil extracted from oilfield reservoirs brings together hypersaline produced water. Failure in pipelines transporting this mixture causes contamination of the soil with oil and hypersaline water. Soil salinization is harmful to biological populations, impairing the biodegradation of contaminants. We simulated the contamination of a soil from an oilfield with produced water containing different concentrations of NaCl and crude oil, in order to evaluate the effect of salinity and hydrocarbon concentration on prokaryote community structure and biodegradation activity. Microcosms were incubated in CO2-measuring respirometer. After the incubation, residual aliphatic hydrocarbons were quantified and were performed 16S rRNA gene sequencing. An increase in CO2 emission and hydrocarbon biodegradation was observed with increasing oil concentration up to 100 g kg-1. Alpha diversity decreased in oil-contaminated soils with an increase in the relative abundance of Actinobacteria and reduction of Bacteroidetes with increasing oil concentration. In the NaCl-contaminated soils, alpha diversity, CO2 emission, and hydrocarbon biodegradation decreased with increasing NaCl concentration. There was an increase in the relative abundance of Firmicutes and Proteobacteria and a reduction of Actinobacteria with increasing salt concentration. Our results highlight the need to adopt specific bioremediation strategies in soils impacted by mixtures of crude oil and hypersaline produced water.

Hydrocarbon solubilisation by oil and cellulose-degrading Chitinophaga terrae isolated from the rumen.

This study investigated the capacity of cellulose and hydrocarbon degrading bacterium isolated from the rumen of a cow to solubilise hydrocarbon. The bacterium was isolated from the rumen fluid of cow and its capacity to degrade cellulose was screened on carboxyl methyl cellulose (CMC) agar plate and the ability to degrade crude oil was carried out using Bonny Light crude. Solubilisation of hydrocarbon was determined by carrying out emulsification index (E24) using kerosene. Other bio-surfactant characteristics such as blood haemolysis, tilted slide capacity and oil displacement were tested also. The bacterium was identified based on phenotypic, biochemical and molecular characteristics. The isolate achieved 48.17% degradation of total petroleum hydrocarbon (TPH) within 14 days with emulsification index of 54.5%. The isolate also produced clear zone on agar plate containing CMC as the sole carbon source. Phylogenetic tree analyses classified the bacterial isolate as Chitinophaga terrae. The sequences have been deposited to GenBank under the accession number KJ076216.1. This study has demonstrated that the novel strain of Chitinophaga terrae used in this study not only has the capacity for multiple substrate utilization, but also has the capacity to produce bio-surfactant. Considering that the isolate was obtain from the rumen of cow it shows that rumen content may harbour bacteria with diverse economical and ecologically-friendly product, which may be utilized for bioremediation of crude oil contaminated systems.