Oil-contaminated Soil Research Articles

Screening and Characterization of Biosurfactant-producing Strains in Contaminated Soil

Biosurfactant obtained from microorganisms isolated from different locations presents an alternative source to chemical surfactant, due to its structural and functional similarity, as well as its biodegradability properties. The goal of this work was to isolate biosurfactant-producing bacterial strains in seven sites with oil-contaminated soils, in district Lucknow, Uttar, India. Drop collapse assay, oil displacement method, emulsification activity and haemolytic assay were used to screen the total of 13 distinct colonies obtained from this study. Isolates GAR-1, TP-2, PET-1 & PET-3 were screened and evaluated to be more potent for biosurfactant production. The molecular identification of GAR-1, TP-2, PET-1 & PET-3 isolates were identified by 16S rRNA sequencing and characterized by FT-IR analysis. A total of 13 bacteria were isolated in the oil-contaminated soils, these four strains with high biosurfactant-production, identified as Bacillus paralicheniformis HRA-IU, B. velezensis NWR-20, Bacillus sp. HUR-IU and P. aeruginosa HUR-IA, respectively. The present study confirms that isolated microorganisms have biosurfactant property and screens the most potent biosurfactant (rhamnolipid) producing strain which is Bacillus sp. HUR-IU.

Biosurfactant production by Bacillus amyloliquefaciens, characterization and its potential applications

Aim: To identify indigenous bacteria responsible for producing biosurfactants in soil contaminated by oil and to investigate their potential uses in the fields of pharmaceuticals and environmental applications. Methodology: The microorganisms of oil-contaminated soil were isolated, screened, and identified using 16S rRNA gene sequencing. Bacillus amyloliquefaciens was utilized to produce biosurfactants, and were characterized by UV, TLC, FTIR, HPTLC, and GCMS analysis. Antibacterial activity, plant growth promotion, biocompatibility, and wound healing activity of surfactant were performed. Results: Six bacterial cultures (B1 to B6) were isolated from the soil samples collected from various locations in Kerala and Tamil Nadu. Among the isolates screened for biosurfactant production, Bacillus amyloliquefaciens exhibited the highest capacity for biosurfactant production, confirmed through 16S rRNA gene sequencing. The biosurfactant produced was identified as surfactin of lipopeptide nature, characterized by various analytical techniques: UV absorption at 400 nm, TLC and HPTLC (Rf value of 0.58), FTIR (prominent peak at 3819 cm-1 corresponding to -OH groups), GCMS with a maximum retention time of 12.03. Surfactin effectively inhibited pathogenic bacteria, enhanced plant growth, was biocompatible, and enhanced the rate of cell migration towards wound scratch. Interpretation: The current study revealed that Bacillus amyloliquefaciens, isolated from oil-contaminated soil, is capable of producing biosurfactant surfactin. Additionally, it unveiled a broad spectrum of applications for surfactin, encompassing wound healing, biocompatibility, antimicrobial activity, and promotion of plant growth. Key words: Antibacterial activity, Biocompatibility, Bacillus amyloliquefaciens, Biosurfactant, Wound healing

Biochar-bacteria-plant combined potential for remediation of oil-contaminated soil.

Oil pollution is a common type of soil organic pollution that is harmful to the ecosystem. Bioremediation, particularly microbe-assisted phytoremediation of oil-contaminated soil, has become a research hotspot in recent years. In order to explore more appropriate bioremediation strategies for soil oil contamination and the mechanism of remediation, we compared the remediation effects of three plants when applied in combination with a microbial agent and biochar. The combined remediation approach of Tagetes erecta, microbial agent, and biochar exhibited the best plant growth and the highest total petroleum hydrocarbons degradation efficiency (76.60%). In addition, all of the remediation methods provided varying degrees of restoration of carbon and nitrogen contents of soils. High-throughput sequencing found that microbial community diversity and richness were enhanced in most restored soils. Some soil microorganisms associated with oil degradation and plant growth promotion such as Cavicella, C1_B045, Sphingomonas, MND1, Bacillus and Ramlibacter were identified in this study, among which Bacillus was the major component in the microbial agent. Bacillus was positively correlated with all soil remediation indicators tested and was substantially enriched in the rhizosphere of T. erecta. Functional gene prediction of the soil bacterial community based on the KEGG database revealed that pathways of carbohydrate metabolism and amino acid metabolism were up-regulated during remediation of oil-contaminated soils. This study provides a potential method for efficient remediation of oil-contaminated soils and thoroughly examines the biochar-bacteria-plant combined remediation mechanisms of oil-contaminated soil, as well as the combined effects from the perspective of soil bacterial communities.

Enhanced bioremediation of hexavalent chromium via Stenotrophomonas acidaminiphila 4–1 assisted with agricultural wastes-derived biochar

Chromium (Cr) contamination in soil poses high toxicity risks to organisms. In this study, a Cr(VI)-resistant strain was isolated from oil-contaminated soil and designated as Stenotrophomonas acidaminiphila 4–1. The optimal removal efficiency of Cr(VI) (67.4 %) was achieved by employing the response surface methodology, with a glucose concentration of 6.1 %, soil moisture content of 31 %, inoculation dose of 4.5 mL, and initial Cr(VI) concentration of 0.2 mg·g−1. The strain 4–1 was immobilized in biochar derived from the pyrolysis of agricultural waste, including corn straw, loofah, and reed straw. In the loofah biochar-4–1 group, the removal efficiency of Cr(VI) was 74.94 % when the initial concentration of Cr(VI) was 0.2 mg·g−1. The biochar-immobilized strain 4–1 exhibited superior removal efficiency and tolerance towards Cr(VI) compared to the single free strain 4–1.The FT-IR results revealed that the surface functional groups of reed straw biochar exhibited a higher abundance compared to those of corn straw biochar and loofah biochar. The predominant form of Cr(VI) in untreated soil was found to be residual form, while the proportion of Fe-Mn oxides form increased from 7.9 % to 18.8 % within a span of 14 days. Notably, loofah biochar-4–1 exhibited the ability to convert unstable chromium species into stable forms within the soil. This work offers a specific instructive method to for remediating Cr polluted sites.

Study of Bacterization of Medicago sativa L. and Cynodon dactylon (L.) Pers. During the Process of Phytoremediation of Oil-contaminated Soils

Recultivation of oil-contaminated soils on the Absheron Peninsula is one of the most important environmental and social problems for this region. One of the promising ways to solve the problem of soil pollution with petroleum hydrocarbons is the development of methods and approaches for their purification and detoxification in situ, and above all, biodetoxification and bioremediation. In a model vegetation experiment using complex systems of a mixture of plants and microorganisms, phytoremediation of soil contaminated with crude oil at a concentration of 15 g/kg was investigated. It has been established that the inoculation of plants with the modified Fermi-Start biological product affects the number of rhizosphere microorganisms that stimulate plant growth, as well as the degree of purification of gray-brown soil from oil. Cynodon dactylon is an effective biosystem for the remediation of oil-contaminated gray-brown soils as it is modified by a culture of an oil-oxidizing microorganism of the Pseudomonas aeruginosa, isolated from oil-contaminated gray-brown soil, the Fermi-Start biological product and belongs to the group of “effective microorganisms”, associated with plants — Medicago sativa. The joint introduction of the Fermi-Start biological product and the culture of P. aeruginosa had the greatest protective effect on seedlings from exposure to crude oil. The height of the shoots increased by 71% compared with the negative control, in parallel, the degree of oil degradation increased to 24%. A significant role of alfalfa in stimulating the number of rhizosphere microorganisms capable of hydrocarbon degradation has been revealed. This is confirmed by data showing that the number of microorganisms in the plant rhizoplane was 1–2 orders of magnitude higher (about 1.1×107 on average) than in the rhizosphere (about 1.4×105 on average), which may be due to secretion of plant root exudates. The results of the research allow us to recommend the use of a plant-microbial biosystem consisting of Medicago sativa and Cynodon dactylon, together with a Fermi-Start modified biological product for phytoremediation of gray-brown soil contaminated with crude oil.

FEATURES OF SOIL-VEGETATION COVER OF REVEGETATED OIL-POLLUTANTED AREAS OF OLIGOTROPHIC BOGS IN THE MIDDLE OF REGION RECLAIMED BY THE CUTTING METHOD

The article provides data on a comparative analysis of the features of vegetation restoration in areas of oligotrophic bogs with a high degree of oil product pollution, located on the territory of an oil field in the Middle Ob region, reclaimed according to standard schemes, widely used in the 2000s, and by cutting off oil-contaminated soil. The total projective vegetation cover (TPVC) of all reclaimed areas mostly reaches standard values (above 30%). The TPVC in areas without cutting is slightly higher than in areas with cutting due to the difference in recovery time in favor of the former. At the same time, the average number of all recorded species in areas with cutting is slightly higher, and they include some oligotrophic vascular plants (heather shrubs, Drosera rotundifolia, Eriophorum vaginatum), which spread much less frequently in areas without cutting. The projective cover of the herb-shrub layer is higher in areas without cutting. The content of oil products in the surface layer of 0-20 cm in areas with cutting is generally lower compared to areas reclaimed by traditional methods. However, even high concentrations (more than 250 g∙kg-1) do not have a significant negative effect on the total projective cover of the grass/herb-shrub layer, while its minimum values are primarily associated with a lack of moisture on high microrelief elements. Similarly, high concentrations of hydrocarbons do not serve as an obstacle to the development of moss cover dominated by sphagnum mosses in areas of cut-off hollows. At the same time, polytrichous and brown mosses were much more sensitive to oil pollution in the form of bitumen crust, and thus avoided areas without cutting.

Evaluating and modeling the efficacy of Stipagrostis plumosa for the phytoremediation of petroleum compounds in crude oil-contaminated soil

ABSTRACT This study focused on using Stipagrostis plumosa for phytoremediation to eliminate total petroleum hydrocarbons (TPHs) and heavy metals (HMs) like cadmium (Cd), chromium (Cr), lead (Pb), and nickel (Ni) from oil-contaminated soil. Conducted over six months at a field-scale without artificial pollutants, soil samples were analyzed using gas chromatography‒mass spectrometry (GC‒MS) for TPHs and inductively coupled plasma-optical emission spectroscopy (ICP‒OES) for HMs. Results after six months revealed that plots with plants had significantly higher average removal percentages for TPHs (61.45%), Cd (39.4%), Cr (46.1%), Pb (41.5%), and Ni (44.2%) compared to the control group (p <0.05). Increased microbial respiration and bacteria populations in planted plots indicated enhanced soil microbial growth. Kinetic rate models aligned well with the first-order kinetic rate model for all pollutants (R2 >0.9). Overall, the study demonstrates that S. plumosa can effectively reduce TPHs and HMs in oil-contaminated soil, making it a promising option for pollutant absorption.

A New Multiphase Apparatus for Testing Soil Permeated with Three Immiscible Fluids

Abstract Oil-contaminated unsaturated soil is a complex multiphase material. In this study, a new triaxial apparatus was developed to independently control/measure its air, oil, and water pressures. Therefore, the suctions associated with air–water, air–oil, and oil–water interfaces can be determined. The apparatus utilizes the hanging column and axis-translation techniques to control suctions in 0∼5 kPa and 5∼600 kPa. It is suitable for investigating water/oil retention, isotropic compression, and triaxial shear behavior of oil-contaminated soil. Using this new apparatus, five tests were conducted to analyze the saturation–pressure (S–P) relationship of sand and sandy silt at various oil and water contents and to evaluate the validity of the axis-translation technique for soil permeated with three nonimmersible fluids. Results showed that the artificial increase of air pressure in the axis-translation technique does not obviously alter the air–water and air–oil suctions at constant oil and water contents. A popular suction–saturation model, which was proposed based on test results of clean sands, showed a good prediction of the air–oil suction. However, the oil–water suction results of sandy silt do not align with the model prediction, suggesting that the model may need to be revised for soils with some silt and clay particles.

Identification of Oil Degrading Bacteria from Oil-Contaminated Soil in the Northeastern Part of Jordan

Identification of Oil Degrading Bacteria from Oil-Contaminated Soil in the Northeastern Part of Jordan

Influence of Organic Waste on Bioremediation of Oil-Contaminated Soil

Influence of Organic Waste on Bioremediation of Oil-Contaminated Soil

Catalase activity as a diagnostic indicator of the health of oil-contaminated soils after remediation.

The work objective was to assess the ecological state of soils by changing the residual oil content and restoring catalase activity after remediation. The soils were selected in various ecosystems: a steppe of the Rostov Region (Haplic Chernozem), beech-hornbeam forests in the Republic of Adygea (Haplic Cambisols), and semi-desert of the Caspian province of the Republic of Kalmykia (Eutric Cambisols). Soil samples were polluted with oil at a concentration of 5% of the soil mass. After that, ameliorants (biochar, nitroammophoska, sodium humate, and Baikal EM-1) were introduced into the oil-contaminated soil. The catalase activity of Haplic Cambisols was stimulated only with the introduction of D2 biochar by 11% relative to the control, and in Haplic Chernozem, catalase was most stimulated with the addition of nitroammophoska D0.5 and D1 by 65% and 57% of the control, respectively. Nitroammophoska in all doses significantly stimulated the enzymatic activity, in Eutric Cambisols by four to six times compared to the control. The range of soil stability determined by catalase activity: Eutric Cambisols > Haplic Chernozem > Haplic Cambisols. Thus, it is most effective to apply biochar in doses of D and D2 and D0.5 and D nitroammophoska during the remediation of oil-contaminated Haplic Chernozem. For the remediation of Haplic Cambisols, it is effective to introduce biochar in dose of D2, and Eutric Cambisols-biochar and sodium humate in dose of D0.5 and nitroammophoska (all doses). The results of the study allow using catalase activity as a very informative and statistically significant diagnostical indicator of the health of oil-contaminated soils after remediation.

Heavy fuel oil-contaminated soil remediation by individual and bioaugmentation-assisted phytoremediation with Medicago sativa and with cold plasma-treated M. sativa.

Developing an optimal environmentally friendly bioremediation strategy for petroleum products is of high interest. This study investigated heavy fuel oil (HFO)-contaminated soil (4 and 6gkg-1) remediation by individual and combined bioaugmentation-assisted phytoremediation with alfalfa (Medicago sativa L.) and with cold plasma (CP)-treated M. sativa. After 14weeks of remediation, HFO removal efficiency was in the range between 61 and 80% depending on HFO concentration and remediation technique. Natural attenuation had the lowest HFO removal rate. As demonstrated by growth rate and biomass acquisition, M. sativa showed good tolerance to HFO contamination. Cultivation of M. sativa enhanced HFO degradation and soil quality improvement. Bioaugmentation-assisted phytoremediation was up to 18% more efficient in HFO removal through alleviated HFO stress to plants, stimulated plant growth, and biomass acquisition. Cold plasma seed treatment enhanced HFO removal by M. sativa at low HFO contamination and in combination with bioaugmentation it resulted in up to 14% better HFO removal compared to remediation with CP non-treated and non-bioaugmented M. sativa. Our results show that the combination of different remediation techniques is an effective soil rehabilitation strategy to remove HFO and improve soil quality. CP plant seed treatment could be a promising option in soil clean-up and valorization.

Bacterial biodegradation of oil-contaminated soil for pollutant abatement contributing to achieve sustainable development goals: A comprehensive review

Petroleum hydrocarbon-induced environmental degradation has escalated, necessitating immediate remediation due to the ongoing growth of communities and modernization of civilization. Both carbon and energy can be obtained from hydrocarbons of petroleum, which are decomposed by a wide variety of microorganisms found in nature. Many times, remediation of places damaged by oil using biological means is accomplished by using bacteria that have such characteristics. Hence, this review attempt to highlight on the oil contaminated soil, source of oil pollution, the composition of oil, the impact of oil contamination on the living organisms additionally, the destiny of oil in the environment, how bacteria distributed in the soil and the most common degradable bacteria and their role in oil biodegradation with some attention on the impact of their enzymes. Also, considering the mechanism of biodegradation of aliphatic and aromatic oil hydrocarbon compounds, how bacteria taking up oil hydrocarbons and the influence of several elements on the processes of oil biodegradation. Furthermore, it; reducing pollution contributes to achieving sustainable development goals.

Composition and Distribution of Organic Compounds in Oil-Contaminated Peat Soils of the Mamontovskoye Field (KhMAO–Yugra)

Composition and Distribution of Organic Compounds in Oil-Contaminated Peat Soils of the Mamontovskoye Field (KhMAO–Yugra)

The Influence of Technogenic Systems and Geological Periods on the Formation of Oil Radioactivity

The article describes the influence of technogenic systems and geological periods on the formation of radioactivity in oil. It is known that damage to equipment by natural radionuclides released during oil refining, processing, transportation has a significant impact on radioactivity in the oil deposit. The influence of the content of organoelements, hydrocarbons, sulfur in oil at different stages of geological development on radioactivity has been proven by scientists in their studies. The impact of metals, organoelement compounds, hydrocarbons, sulfur compounds contained in oil in studies of oil-contaminated soils, oil sludge of the Kumkol deposit is shown as a result of qualitative analysis with the mobile application «RD» and the spectrometer «Spectroscan mass». As a result of the study, it can be seen that high radioactivity is present in the sludge and soil with highly contaminated oil.

Effectiveness of biogeosorbents based on mineral carriers for treatment oil-contaminated soil

Methods for cleaning oil-contaminated areas include the use of sorbents, the effectiveness of which is enhanced by the immobilization of hydrocarbon-oxidizing microorganisms on their surface. Biogeosorbents are obtained on the basis of mineral raw materials (analcime- and glauconite-containing rocks and thermally activated vermiculite) and hydrocarbon-oxidizing bacteria of the genera Pseudomonas and Microbacterium extracted from contaminated soils of the Murmansk region. The number of immobilized bacteria on the studied carriers remains high throughout 9 months of storage, and the bacterial film on the surface of mineral carriers persists for 12 months of storage in an air-dry state. When storing biogeosorbents, no special conditions or additional preparation are required before use. Mineral carriers have a stimulating effect on the height of seedlings and the length of roots of test plants. When biogeosorbents are added, the number of bacteria capable of microbiological transformation of petroleum products increases, and the degree of soil purification from petroleum hydrocarbons at the initial stage (during the first 30 days) increases. The most effective is the introduction of thermally activated vermiculite and glauconite-containing rock with immobilized hydrocarbon-oxidizing bacteria. The use of a biogeosorbent based on thermally activated vermiculite can reduce the cleaning time to 20–22 months, and based on glauconite-containing rock – up to 17 months, while without treatment this period will be at least 29 months.

Environmental factors influencing the soil-air partitioning of semi-volatile petroleum hydrocarbons: Laboratory measurements and optimization model

The soil-air partition coefficient (KSA) values are commonly utilized to examine the fate of organic contaminants in soils; however, their measurement has been lacking for semi-volatile petroleum hydrocarbons within soil contaminated by crude oil. This research utilized a solid-phase fugacity meter to determine the KSA values of n-alkanes and polycyclic aromatic hydrocarbons (PAHs) under crucial environmental conditions. The results showed a notable increase in KSA values with the extent of crude oil contamination in soil. Specifically, in the 3 % crude oil treatment, the KSA values for n-alkanes and PAHs increased by 1.16 and 0.66 times, respectively, compared to the 1 % crude oil treatment. However, the KSA values decreased with changes in temperature, water content, and particle size within the specified experimental range. Among these factors, temperature played a significant role. The KSA values for n-alkanes and PAHs decreased by 0.27–0.89 and 0.61–0.83 times, respectively, with a temperature increase from 5 °C to 35 °C. Moreover, the research identified that the molecular weight of n-alkanes and PAHs contributed to variations in KSA values under identical environmental factors. With an increase in temperature from 5 °C to 35 °C, the range of n-alkanes present in the air phase expanded from C11 to C34, and PAHs showed elevated levels of acenaphthene (ACE) and benzo (b) fluoranthene (BbFA). Furthermore, heightened water content and particle size were observed to facilitate the volatilization of low molecular weight petroleum hydrocarbons. The effect of environmental variables on soil-air partitioning was evaluated using the Box-Behnken design (BBD) model, resulting in the attainment of the lowest log KSA values. These results illustrate that soil-air partitioning is a complex process influenced by various factors. In conclusion, this study improves our comprehension and predictive capabilities concerning the behavior and fate of n-alkanes and PAHs within soil-air systems.

Bioremediation of Oil-Contaminated Soils of the Zhanazhol Deposit from West Kazakhstan by Pseudomonas mendocina H-3

The culture of Pseudomonas mendocina H-3 was selected as the microorganism for oil destruction, and its effect on oil-contaminated soil from the Zhanazhol deposit in West Kazakhstan was studied. After conducting model laboratory experiments, field experiments were carried out. Six and twelve months after the treatment of the oil-contaminated field with microorganisms, the amount of oil fractions in the soil decreased noticeably, while the content of asphaltenes remained constant. Analyses show that the composition of the oil fraction changes—the concentration of paraffin-naphthenic—polycycloaromatic components decreases, whereas the relative amount of mono- and bicycloaromatic hydrocarbons increases. The results of the efficiency assessment showed that the use of Pseudomonas mendocina H-3 cell suspension in natural conditions leads to a decrease in the content of hydrocarbons in the soil from 55 to 70%. The lower efficiency of bioremediation with cell cultures in field experiments (on average, 61%) compared with laboratory model studies (reduction of oil content to 79%) is apparently associated with climatic conditions.

Accelerated technology for cleaning oil-contaminated soils

Relevance. The uniqueness of the practical application of accelerated and environmentally safe technology for the reclamation of oil–polluted lands, which uses local mineral raw materials, a consortium of autochthonous hydrocarbon-oxidizing bacteria with multifunctional positive properties, effective phytomeliorants, is theoretically substantiated. Hydrocarbon pollution is eliminated directly at the spill site, and the rate ofreturn of disturbed soils to agricultural circulation is 3–4 times faster than traditional methods.Methods. Objects of research: mechanically activated bentopowder and nanobentonite, a consortium of hydrocarbon-oxidizing bacteria composed of three autochthonous strains, soil leached chernozem, spring wheat, Devonian oil. The concentration of oil pollution at the site was 6.4%. Bentopowder and nanobentonite were introduced in doses of 6.0 t/ha and 0.3 t/ha, respectively. Sampling was carried out with a sampler on the 0th, 15th, 30th, and 90th days.Results. The optimal doses of application of bento powder and nano bentonite to disturbed soil above the average pollution level (6.0 t/ha and 0.3 t/ha respectively) are recommended. After 15 days, the level of contamination is halved (to 51.1 g/kg and 40.8 g/kg with benton powder and nanobentonite respectively). Removal of the introduced mineral sorbent is not required, since it later becomes a source of mineral nutrition for autochthonous microorganisms-destructors and a soil improver. At the second innovative stage, a consortium formed from effective strains and adapted to specific conditions is used. The strains of the consortium fit into an ecological niche, adapt and begin to actively develop, utilizing oil and petroleum products. After a month, the level of contamination decreases to 19.2 g/kg and 9.2 g/kg with the addition of benton powder and nanobentonite respectively.

Microemulsion phase behavior based on biodiesel and its performance in treating oil-contaminated soil

Biodiesel-based microemulsions have unique advantages in the treatment of petroleum-contaminated soils, thanks to their ultra-low interfacial tension and strong solubility. By studying the effects of different solvents, surfactants, and co-surfactants on the phase transition of the microemulsion, and comparing the effects of temperature, solid-liquid ratio, and treatment time on washing efficiency, we successfully obtained the composition of a biodiesel-based microemulsion system with high stability and optimized washing conditions. At the same time, the deactivation mechanism in the washing process of the microemulsion was analyzed. The experimental results showed that the biodiesel microemulsion, composed of SDBS as a surfactant and n-butanol as a co-surfactant, exhibited excellent washing stability. The optimized washing conditions were as follows: temperature of 35℃, 1:5 solid-liquid ratio, and 30-minute treatment time. Under these conditions, the oil removal rate reached as high as 73.6%. The reasons for the microemulsion inactivation may be as follows: (1) Composition loss of the microemulsion during the washing process leads to a reduction in washing efficiency; (2) During the washing process, solid particles formed a hard shell on the surface of the microemulsion droplets, reducing the washing efficiency; (3) Oil components eluted from the soil entered the oil phase of the microemulsion, changing the oil phase composition and resulting in decreased washing efficiency.