Bioremediation Of Petroleum Hydrocarbon-contaminated Soil Research Articles

Application of Organic Amendment from Kitchen Waste Composting for Enhanced Bioremediation of Petroleum Hydrocarbon-Contaminated Soil

Application of Organic Amendment from Kitchen Waste Composting for Enhanced Bioremediation of Petroleum Hydrocarbon-Contaminated Soil

Remediation of petroleum contaminated soil by persulfate oxidation coupled with microbial degradation

This study was conducted on soil polluted with high concentrations of crude oil (12,835 ± 572.76 mg/kg) with different dosages of persulfate (PS) coupled with hydrocarbon-degrading mixed bacteria (including Enterobacteriaceae, Stenotrophomonas, Pseudomonas, Acinetobacter, and Achromobacter) obtained from long-term oil-contaminated soil. The interaction among total petroleum hydrocarbons (TPH), soil parameters, and microbial communities during a 187-d combined remediation process was evaluated. The result showed that the TPH removal of 1% PS oxidation combined with bioremediation was 80.05%; this was 4.88% and 20.94% higher than that of bioremediation and 1% PS oxidation combined with natural attenuation. This is a result of 1%PS stimulated enzyme secretion and dissolved organic carbon content, especially fulvic acid, improving TPH mobility and bioavailability in soil. Furthermore, introducing mixed bacteria after oxidation further increased enzyme activities and TPH-degrading ability, thus promoting carbon substrate conversion and biodegradation rate. Conversely, the excessive oxidation of 3% and 5% PS had a negative impact on the soil environment and microbial diversity resulting in lower TPH degradation (36%-57%). High-throughput sequencing revealed that the abundance and diversity of soil bacteria decreased in all remediation groups compared to those in the pristine soil. Redundancy analysis showed that the main factors affecting 1% PS oxidation combined with bioremediation during subsequent microbial remediation were pH, cation exchange capacity, and lipase activity, which may indirectly influence TPH biodegradation by increasing the abundance of genus Immundisolibacteraceae, Comamonadaceae, and Acinetobacter. This study provides data on in situ chemical oxidation integrated with the bioremediation of petroleum hydrocarbon-contaminated soils.

Metagenomic analysis of microbial communities across a transect from low to highly hydrocarbon-contaminated soils in King George Island, Maritime Antarctica.

Soil samples from a transect from low to highly hydrocarbon-contaminated soils were collected around the Brazilian Antarctic Station Comandante Ferraz (EACF), located at King George Island, Antarctica. Quantitative PCR (qPCR) analysis of bacterial 16S rRNA genes, 16S rRNA gene (iTag), and shotgun metagenomic sequencing were used to characterize microbial community structure and the potential for petroleum degradation by indigenous microbes. Hydrocarbon contamination did not affect bacterial abundance in EACF soils (bacterial 16S rRNA gene qPCR). However, analysis of 16S rRNA gene sequences revealed a successive change in the microbial community along the pollution gradient. Microbial richness and diversity decreased with the increase of hydrocarbon concentration in EACF soils. The abundance of Cytophaga, Methyloversatilis, Polaromonas, and Williamsia was positively correlated (p-value=<.05) with the concentration of total petroleum hydrocarbons (TPH) and/or polycyclic aromatic hydrocarbons (PAH). Annotation of metagenomic data revealed that the most abundant hydrocarbon degradation pathway in EACF soils was related to alkyl derivative-PAH degradation (mainly methylnaphthalenes) via the CYP450 enzyme family. The abundance of genes related to nitrogen fixation increased in EACF soils as the concentration of hydrocarbons increased. The results obtained here are valuable for the future of bioremediation of petroleum hydrocarbon-contaminated soils in polar environments.

Alternating current enhanced bioremediation of petroleum hydrocarbon-contaminated soils.

In this work, bioremediation was applied with sinusoidal alternating current (AC) electric fields to remove petroleum hydrocarbon (TPH) for soil remediation. Applying AC electric field with bioremediation (AC+BIO) could efficiently remove 31.6% of the TPH in 21 days, much faster than that in the BIO only system (13.7%) and AC only system (5.5%). When the operation time extended to 119 days, the AC+BIO system could remove 73.3% of the TPH. Applying AC electric field (20-200 V/m) could maintain the soil pH at neutral, superior to the direct current electric field. The maximum difference between soil temperature and the room temperature was 1.9 °C in the AC (50 V/m) +BIO system. The effects of AC voltage gradient (20-200 V/m) on the microorganisms and TPH degradation efficiency by AC+BIO were investigated, and the optimized AC voltage gradient was assessed as 50 V/m for lab-scale experiments. The microbial community structures in the BIO and AC+BIO systems were compared. Although Pseudomonas was the dominant species, Firmicutes became more abundant in the AC+BIO system than the BIO system, indicating their adaptive capacity to the stress of the AC electric field. Real petroleum-contaminated soil was used as a reaction matrix to evaluate the performance of AC+BIO in the field. The initial current density was about 0.2 mA/cm2, voltage gradient was about 20 V/m, and the average TPH degradation rate was 8.1 μg/gdry soil per day. This study provided insights and fundamental supports for the applications of AC+BIO to treat petroleum-polluted soils.

Petroleum hydrocarbon-contaminated soil bioremediation assisted by isolated bacterial consortium and sophorolipid.

Pollution in soil by petroleum hydrocarbon has become a global environmental problem. The bioremediation of petroleum hydrocarbon-contaminated soil was enhanced with the combination of an isolated indigenous bacterial consortium and biosurfactant. The biodegradation efficiency of total petroleum hydrocarbon (TPH) was increased from 12.2% in the contaminated soil to 44.5% and 57.7% in isolated consortium and isolated consortium & 1.5g sophorolipid (SL)/kg dry soil, respectively. The half-life of TPH degradation process was decreased from 32.5d in the isolated consortium reactor to 20.4d in the isolated consortium & 1.5g SL/kg dry soil. The addition of biosurfactant into contaminated soils improved the TPH desorption from solid matrix to the aqueous solution and the subsequent solubilization, which ultimately improved the bioavailability of TPH in contaminated soils. Biosurfactant also served as carbon sources which contributed to the stimulation of cell growth and microbial activity and accelerated the biodegradation process via co-metabolism. The enzyme activities and quantities of functional genes were demonstrated to be incremented in SL reactors. The biosurfactant improved the TPH bioavailability, stimulated the microbial activities and participated in the co-metabolism. The combination of bioaugmentation and SL benefitted the bioremediation of petroleum hydrocarbon-contaminated soil.

Succession of microbial communities and synergetic effects during bioremediation of petroleum hydrocarbon-contaminated soil enhanced by chemical oxidation

Biotechnologies integrated with chemical techniques are promising in treating the soils contaminated by petroleum hydrocarbons. Experiments by applying the degrading consortium and the modified Fenton (MF) with the chelator sodium citrate simultaneously were carried out to investigate the effects of the MF reagents on the degradation of total petroleum hydrocarbons (TPHs), changes in enzyme activities and the succession of microbial communities at the 0, 20, 100 and 500 mmol/kg hydrogen peroxide concentration levels. The ratio between hydrogen peroxide, ferrous sulfate and sodium citrate in the MF reagents was 100:1:1. The results indicated that the degradation of TPHs conformed to first-order kinetics and MF treatments increased the total removal rates of TPHs (4.73–24.26%) and activated dehydrogenase and polyphenol oxidase activities. A shift in microbial communities from Proteobacteria to Bacteroidetes was observed during the enhanced bioremediation, and the predominant genus shifted from Pseudomonas with an average relative abundance (ARAs) of 76.61% at the beginning to Sphingobacterium with ARAs of 52.06% at the later stage. The MF reagents at the proper level could simplify the relationship among the community populations, alleviate their competition and strengthen their associations, which would optimize the removal efficiency.

Bioremediation of petroleum hydrocarbon-contaminated soil by petroleum-degrading bacteria immobilized on biochar.

Biochar is investigated experimentally as a new highly effective amendment to remediate contaminated soil. A crucial consideration is the influence of biochar on the bioremediation of soil polluted with total petroleum hydrocarbons (TPHs), and in particular, the use of biochar as a bacteria immobilization carrier with a synergistic effect of absorption and degradation. Therefore, we studied the ability of petroleum-degrading bacteria immobilized on biochar, free bacteria, and biochar alone on the removal of TPHs in soil using gravimetric analysis and gas chromatography-mass spectrometry. After 60 days of remediation, the strategy involving immobilized bacteria on biochar was more effective than other treatments in reducing the contents of TPHs and n-alkanes with C12–18, which showed the shortest half-life and highest biodegradation efficiency; variations in the features of enzymatic activities and microbial respiration indicated that the biochar treatment improved not only the soil fertilizer and carbon storage, but the immobilization greatly affected both the physicochemical properties of soil and bacterial activities. Moreover, the bacterial population diversity and bioavailability of hydrocarbons were promoted by the inputs of the combination of biochar and petroleum-degrading bacteria. Overall, our results highlight the potential of applying immobilized microorganisms on biochar for accelerating the biodegradation of petroleum and maintaining the balance of the soil ecosystem, which may be ascribed to the synergistic effect of biostimulation and bioaugmentation.

Ability of Agaricus bisporus, Pleurotus ostreatus and Ganoderma lucidum compost in biodegradation of petroleum hydrocarbon-contaminated soil

Use of the white rot fungi in bioremediation is effective in degrading of organic petroleum hydrocarbon-contaminated soil. The rate of degradation depends on nature of microflora and environmental characteristics of an oil-contaminated ecosystem. The spent mushroom compost of Agaricus bisporus, Pleurotus ostreatus and Ganoderma lucidum were used as inoculums (10%) for bioremediation of petroleum hydrocarbon-contaminated soil from the Esfahan Oil Refinery Company. The soils were kept at 25–28 °C and maintained at 60% water holding capacity. To provide the necessary aeration, the soils were tilled twice a week by shovel. Ecotoxicity testing was performed on dried soil sample, and residual oil was measured by gas chromatography. The petroleum hydrocarbons were degraded by all composts of white rot fungi. However, only A. bisporus showed a higher ability to degrade total petroleum hydrocarbons (71.5%). The results showed that the hydrocarbon remediation rate in all the treatments by A. bisporus, P. ostreatus and G. lucidum increased with time. Gas chromatography results showed total petroleum hydrocarbon decreased in all treatments. The result showed that spent mushroom compost degrades petroleum hydrocarbons residues in contaminated soil of Esfahan Refinery and reduced toxicity of this soil during 3 months.

Biosurfactant production by Pseudomonas aeruginosa DSVP20 isolated from petroleum hydrocarbon-contaminated soil and its physicochemical characterization.

Among 348 microbial strains isolated from petroleum hydrocarbon-contaminated soil, five were selected for their ability to produce biosurfactant based on battery of screening assay including hemolytic activity, surface tension reduction, drop collapse assay, emulsification activity, and cell surface hydrophobicity studies. Of these, bacterial isolate DSVP20 was identified as Pseudomonas aeruginosa (NCBI GenBank accession no. GQ865644) based on biochemical characterization and the 16S rDNA analysis, and it was found to be a potential candidate for biosurfactant production. Maximum biosurfactant production recorded by P. aeruginosa DSVP20 was 6.7 g/l after 72 h at 150 rpm and at a temperature of 30 °C. Chromatographic analysis and high-performance liquid chromatography-mass spectrometry (HPLC-MS) revealed that it was a glycolipid in nature which was further confirmed by nuclear magnetic resonance (NMR) spectroscopy. Bioremediation studies using purified biosurfactant showed that P. aeruginosa DSVP20 has the ability to degrade eicosane (97%), pristane (75%), and fluoranthene (47%) when studied at different time intervals for a total of 7 days. The results of this study showed that the P. aeruginosa DSVP20 and/or biosurfactant produced by this isolate have the potential role in bioremediation of petroleum hydrocarbon-contaminated soil.

Pilot-scale bioremediation of a petroleum hydrocarbon-contaminated clayey soil from a sub-Arctic site

Bioremediation is a potentially cost-effective solution for petroleum contamination in cold region sites. This study investigates the extent of biodegradation of petroleum hydrocarbons (C16–C34) in a pilot-scale biopile experiment conducted at 15°C for periods up to 385 days, with a clayey soil, from a crude oil-impacted site in northern Canada. Although several studies on bioremediation of petroleum hydrocarbon-contaminated soils from cold region sites have been reported for coarse-textured, sandy soils, there are limited studies of bioremediation of petroleum contamination in fine-textured, clayey soils. Our results indicate that aeration and moisture addition was sufficient for achieving 47% biodegradation and an endpoint of 530mg/kg for non-volatile (C16–C34) petroleum hydrocarbons. Nutrient amendment with 95mg-N/kg showed no significant effect on biodegradation compared to a control system without nutrient but similar moisture content. In contrast, in a biopile amended with 1340 mg-N/kg, no statistically significant biodegradation of non-volatile fraction was detected. Terminal Restriction Fragment Length Polymorphism (T-RFLP) analyses of alkB and 16S rRNA genes revealed that inhibition of hydrocarbon biodegradation was associated with a lack of change in microbial community composition. Overall, our data suggests that biopiles are feasible for attaining the bioremediation endpoint in clayey soils. Despite the significantly lower biodegradation rate of 0.009day−1 in biopile tank compared to 0.11day−1 in slurry bioreactors for C16–C34 hydrocarbons, the biodegradation extents for this fraction were comparable in these two systems.

Bioremediation of petroleum hydrocarbons-contaminated soil by bacterial consortium isolated from an industrial wastewater treatment plant

BACKGROUND Bioaugmentation is a promising technology to clean up sites contaminated by the petrochemical industry. The paper reports on the bioremediation of a refinery soil containing hydrocarbons in a semi-arid climate and its impact on the soil microbial community. Two trial plots were established in autumn 2008 to compare two sets of conditions. The first trial is a control (contaminated soil with indigenous microorganismes) and the second is a trial where an acclimatized bacterial consortium was added. RESULTS The proposed bioremediation technology resulted in significantly higher hydrocarbons removal efficiencies than the control. The total amount of petroleum hydrocarbon (TPH) was decreased from 63.4 mg g−1 to 2.5 mg g−1 at the end of the treatment. The treated soil could be considered non-phytotoxic since the germination index of Lepidium sativum ranged between 80 and 115%. Further, a GC/MS profile proved that the acclimatized bacterial consortium could effectively remove medium- and long-chain alkanes in the contaminated soil after a 30-day treatment period. Microbial community analysis (16S rRNA and Denaturing Gradient Gel Electrophoresis (DGGE) fingerprints) confirmed the dominance of hydrocarbon degrading genera such as actinobacteria and gamma-proteobacteria phyla. CONCLUSION These results show that bioaugmentation may be a suitable tool for the remediation of soil contaminated with petroleum hydrocarbons. © 2013 Society of Chemical Industry

Effect of scale-up and seasonal variation on biokinetics in the enhanced bioremediation of petroleum hydrocarbon-contaminated soil

The biodegradation rate of petroleum hydrocarbon-contaminated soil was evaluated by the effect of temperature variation through bioaugmentation and biostimulation. In this study, biokinetics of batch-, pilot-, and field-scale biodegradation were performed by the optimization of enhanced biodegradation, minimizing the inhibitory effects of seasonal variations such as the rainy and cold winter seasons. From the relationship between remedial timescale and initial concentration, the biokinetic isolines of the biodegradation were smaller in the winter than those in the other seasons. The scale-up of biodegradation process led to enhance its activation energy, and then the field-scale remedial action should be performed in the way to lower the activation energy from the chemical diffusion and microbial activation. Therefore, a remedial or field worker can obtain the remedial timescale from the given apparent data of biokinetics with respect to initial TPH concentration only after the simple remedial investigation.

Microbial degradation of polycyclic aromatic hydrocarbons in soil by bacterium-fungus co-cultures

Two fungi and the phenanthrene-degrading bacterial strainRhodococcus sp. IC10 were used as inocula for the bioremediation of petroleum hydrocarbon-contaminated soil from a manufactured gas plant area. The two fungi, which were previously isolated from different hydrocarbon-contaminated soil samples, were identified asAspergillus terreus andPenicillium sp. In addition, two types of co-cultures which consist of fungal species includingA. terreus orPenicilium sp. withRhodococcus sp. IC10 were applied. After a 10-week incubation period, the concentrations of anthracene, phenanthrene, and pyrene were totally biodegraded by days 68, 54, and 64, for the 16 polycyclic aromatic hydrocarbons (PAH's) tested. The ecotoxicity of the soil after bioremediation did not show any effect on the survival ofDaphnia magna (24 h-old-daphnids). However, the toxicity on seed germination ofBrassica alba and the oxidoreductase activity ofBacillus cereus declined after 5- and 10-weeks of incubation, respectively. Co-cultures ofPenicillium sp. andRhodococcus sp. IC 10 revealed the best efficiency at reducing ecotoxicity.

Basics of diagnostic PCR assay design

Pollution in soil by petroleum hydrocarbon has become a global environmental problem. The bioremediation of petroleum hydrocarbon-contaminated soil was enhanced with the combination of an isolated indigenous bacterial consortium and biosurfactant. The biodegradation efficiency of total petroleum hydrocarbon (TPH) was increased from 12.2% in the contaminated soil to 44.5% and 57.7% in isolated consortium and isolated consortium & 1.5 g sophorolipid (SL)/kg dry soil, respectively. The half-life of TPH degradation process was decreased from 32.5 d in the isolated consortium reactor to 20.4 d in the isolated consortium & 1.5 g SL/kg dry soil. The addition of biosurfactant into contaminated soils improved the TPH desorption from solid matrix to the aqueous solution and the subsequent solubilization, which ultimately improved the bioavailability of TPH in contaminated soils. Biosurfactant also served as carbon sources which contributed to the stimulation of cell growth and microbial activity and accelerated the biodegradation process via co-metabolism. The enzyme activities and quantities of functional genes were demonstrated to be incremented in SL reactors. The biosurfactant improved the TPH bioavailability, stimulated the microbial activities and participated in the co-metabolism. The combination of bioaugmentation and SL benefitted the bioremediation of petroleum hydrocarbon-contaminated soil.

Use of fungal technology in soil remediation: A Case Study

Two white rot fungi Irpex lacteus and Pleurotus ostreatus and a PAH-degrading bacterial strain of Pseudomonas putida were used as inoculum for bioremediation of petroleum hydrocarbon-contaminated soil from a manufactured-gas-plant-area. Also two cocultures comprising a fungus with Pseudomonas putida were applied. After 10-week treatment out of 12 different PAHs, concentration of phenanthrene, anthracene, fluoranthene and pyrene decreased up to 66%. The ecotoxicity of the soil after bioremediation did not reveal any effect on the survival of Daphnia magna, a crustacian. However, the toxic effect on seed germination of plant Brassicaalba and oxidoreductase activity of bacterium Bacillus cereus decreased after 5 and 10 weeks of treatment.

Bioremediation of petroleum hydrocarbon-contaminated soil by composting in biopiles

Composting of contaminated soil in biopiles is an ex situ technology, where organic matter such as bark chips are added to contaminated soil as a bulking agent. Composting of lubricating oil-contaminated soil was performed in field scale ( 5×40 m 3) using bark chips as the bulking agent, and two commercially available mixed microbial inocula as well as the effect of the level of added nutrients (N,P,K) were tested. Composting of diesel oil-contaminated soil was also performed at one level of nutrient addition and with no inoculum. The mineral oil degradation rate was most rapid during the first months, and it followed a typical first order degradation curve. During 5 months, composting of the mineral oil decreased in all piles with lubrication oil from approximately 2400 to 700 mg (kg dry w) −1, which was about 70% of the mineral oil content. Correspondingly, the mineral oil content in the pile with diesel oil-contaminated soil decreased with 71% from 700 to 200 mg (kg dry w) −1. In this type of treatment with addition of a large amount of organic matter, the general microbial activity as measured by soil respiration was enhanced and no particular effect of added inocula was observed.