Bioremediation Of Petroleum-contaminated Soil Research Articles

Enhancing soil petrochemical contaminant remediation through nutrient addition and exogenous bacterial introduction

Biostimulation (providing favorable environmental conditions for microbial growth) and bioaugmentation (introducing exogenous microorganisms) are effective approaches in the bioremediation of petroleum-contaminated soil. However, uncertainty remains in the effectiveness of these two approaches in practical application. In this study, we constructed mesocosms using petroleum hydrocarbon-contaminated soil. We compared the effects of adding nutrients, introducing exogenous bacterial degraders, and their combination on remediating petroleum contamination in the soil. Adding nutrients more effectively accelerated total petroleum hydrocarbon (TPH) degradation than other treatments in the initial 60 days’ incubation. Despite both approaches stimulating bacterial richness, the community turnover caused by nutrient addition was gentler than bacterial degrader introduction. As TPH concentrations decreased, we observed a succession in microbial communities characterized by a decline in copiotrophic, fast-growing bacterial r-strategists with high rRNA operon (rrn) copy numbers. Ecological network analysis indicated that both nutrient addition and bacterial degrader introduction enhanced the complexity and stability of bacterial networks. Compared to the other treatment, the bacterial network with nutrient addition had more keystone species and a higher proportion of negative associations, factors that may enhance microbial community stability. Our study demonstrated that nutrient addition effectively regulates community succession and ecological interaction to accelerate the soil TPH degradation.

Bioremediation of Petroleum-Contaminated Soils with Biosurfactant-Producing Degraders Isolated from the Native Desert Soils.

A crude oil spill in 2014 resulted in extensive soil contamination of the hyper arid Evrona Nature Reserve in Israel's Negev Desert. The contaminated soils became highly hydrophobic, threatening the existence of plants in the habitat. We hypothesized that bioaugmenting the soil with indigenous biosurfactant-producing, hydrocarbon-degrading bacteria (HDB) would accelerate the reduction in the soil's hydrophobicity. We aimed to isolate and characterize biosurfactant-producing HDBs from the desert-contaminated soil and test if they can be used for augmenting the soil. Twelve hydrocarbon-degrading strains were isolated, identified as Pseudomonas, and classified as biosurfactants "producing" and "nonproducing". Inoculating 109 CFU/g of "producing" strains into the polluted soil resulted in a 99.2% reduction in soil hydrophobicity within seven days. At the same time, nonproducing strains reduced hydrophobicity by only 17%, while no change was observed in the untreated control. The microbial community in the inoculated soil was dominated by the introduced strains over 28 days, pointing to their persistence. Rhamnolipid biosynthesis gene rhlAB remained persistent in soil inoculated with biosurfactants, indicating in situ production. We propose that the success of the treatment is due to the use of inoculum enriched from the polluted soil.

Correction to: Bioremediation of petroleum-contaminated soil in arid region using different arid-tolerant tree, shrub, and grass plant species with bacteria

Correction to: Bioremediation of petroleum-contaminated soil in arid region using different arid-tolerant tree, shrub, and grass plant species with bacteria

Bioremediation of petroleum-contaminated soil in arid region using different arid-tolerant tree, shrub, and grass plant species with bacteria

Bioremediation of petroleum-contaminated soil in arid region using different arid-tolerant tree, shrub, and grass plant species with bacteria

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

Bioremediation of petroleum-contaminated soil by semi-aerobic aged refuse biofilter: Optimization and mechanism

Petroleum-contaminated soil (PCS) is a global environmental issue. An effective remediation technique is urgently needed to address this problem. This study applied a semi-aerobic aged refuse biofilter (SAARB) to the decontamination and remediation of PCS. The effects of petroleum content, surfactant content, and water content on oil removal efficiency were studied, and the operation conditions were optimized using the response surface method. Results showed that contents of petroleum and water that were too high or too low depressed total petroleum hydrocarbon (TPH) removal. The presence of surfactant markedly reduced the TPH removal efficiency. The optimal operation conditions were the ratio of aged refuse to PCS = 1.6; water content = 41%; and petroleum content = 3.8%. The TPH removal efficiencies under optimized conditions and during a confirmatory experiment were 59.89% and 51.38%, respectively. PCS contained an abundance of polycyclic aromatic hydrocarbons and macro molecular alkanes, and these organic compounds were considerably removed by SAARB treatment. The microbial community exhibited a marked change at both phylum level and genus level after 3 months of remediation in the PCS. At the genus level, norank_f_SS1–B-06-26 became the most dominant; further isolation and verification experiments for its ability to degrade petroleum are needed. In addition, the abundance of norank_o_Saccharimonadales, Aquabacterium, Hydrogenophaga, and norank_f_Saccharimonadaceae, which can degrade hydrocarbons, also increased. This study provides a theoretical reference for SAARB application in the remediation of PCS.

Characteristics of organic carbon metabolism and bioremediation of petroleum-contaminated soil by a mesophilic aerobic biopile system

An innovative mesophilic aerobic biopile technology was explored to improve the bioremediation efficiency of petroleum-contaminated soil. Under the suitable soil conditions (C:N:P at 100:5:1 and soil moisture content at 18%), the soil pH was hold in the range of 7.4 to 6.8 throughout the bioremediation process, the mesophilic (30 °C-40 °C) and forced aeration (3 h-on/1 h-off) conditions were the critical factors to enhancing petroleum biodegradation. The consumption of bioavailable organic carbon (BAC) which was one of the most important factors regulating microbial metabolism, was positively related (R2 = 0.85, 40 °C) with the rate of petroleum removal. The 50% threshold of BAC could be regarded as the signal for supplementing the soil nutrients in the mesophilic aerobic biopiles to favor petroleum removal. The optimal conditions (40 °C, 3 h-on/1 h-off) maximized the utilization of BAC, promoted the petroleum degradation, and remained the microbial abundance and community composition stable to the greatest extent. In addition, the accumulation of aliphatic acids affected the microbial activity, which limited the efficiency of petroleum degradation to a certain extent. Jointly considering the energy consumption, time cost and soil conditions maintenance, a cost-effective biopile technology was obtained by temperature and aeration regulation and BAC supplementation, which could be applied to engineering application.

Performance and Kinetics of Bioaugmentation, Biostimulation, and Natural Attenuation Processes for Bioremediation of Crude Oil-Contaminated Soils

Bioremediation of contaminated sites is usually limited due to the inadequate availability of nutrients and microorganisms. This study was conducted to assess the impact of bioaugmentation (BA) and biostimulation (BS) on petroleum hydrocarbon degradation efficiency. In addition, treatment performance and kinetics of different remediation processes were investigated. For this purpose, four tanks containing oil-contaminated soils were tested. Tank 1 was operated as the natural attenuation process. Then, a microbial inoculum and nutrients were added to tank 2 to promote BA and BS. In tank 3, only the BA process was adopted, whereas in tank 4, only the BS process was adopted. After 63 days of operation, the total petroleum hydrocarbon (TPH) in tank 2 was reduced from 1674 to 430 mg/kg, with 74% reduction. Tank 1, tank 3, and tank 4 indicated TPH reductions of 35%, 41%, and 66%, respectively. Microbiological analysis of the inoculum indicated that Alcanivorax was the dominant bacterium. The population of TPH degrader bacteria in tank 2 soil was two orders of magnitude higher than in the control tank. Reaction rate data were fitted with a first-order reaction rate model. The Monod kinetic constants, maximum specific growth rate (µmax), and substrate concentration at half-velocity constant (Ks) were also estimated. This study showed that the TPH removal efficiency in the combined BA and BS process was higher than in other processes tested. The populations of TPH degrading microorganisms in soil tanks were positively related to TPH removal efficiency during bioremediation of petroleum-contaminated soils.

Comparative Assessment of Crude Oil Degradation by &lt;i&gt;Monocillium sp.&lt;/i&gt; and &lt;i&gt;Aspergillus niger&lt;/i&gt;

Fungi dwelling in soils contaminated by petroleum products can survive on these hydrocarbons due to the highly effective extracellular enzymes. Species belonging to the genus, Aspergillus are known to be efficient degraders of various classes of hydrocarbons as well as other organic contaminants. In this study, the biodegradation of crude oil by Aspergillus niger and Monocillium sp. were compared using laboratory microcosms.The moulds were isolated from a site receiving effluent from a petroleum refinery. They were identified using their macroscopic and microscopic characteristics and subsequently screened for their ability to utilize hydrocarbons for their metabolic requirements. Following the biodegradation studies, Aspergillus niger and Monocillium sp. recorded an increase in hydrocarbon utilizing fungal counts of 8.5 x 107 spores/ml and 6.1 x 107 spores/ml and crude oil weight loss of 80 % and 70 %. Both fungi were tested singly and in a consortium for their ability to degrade crude oil, itwas observed that Monocillium sp. and A.niger performed better when tested individually (94.2 %; 92.8 %) than in consortium (76.3 %). This may suggest that their combined metabolism may have created some antagonistic effect on the degradation process as opposed to their enzymatic capabilities which appeared to be more favourable to the process. The biodegradation experiment analysis showed that contact time plays a significant role in biodegradation of crude oil (p&lt;0.05), and Monocillium sp. and Aspergillus niger are excellent crude oil degraders and can be usedin the bioremediation of petroleum-contaminated soil and water. &#x0D; Keywords: Biodegradation, Aspergillus niger, Monocillium sp., soil, Crude oil

Synergistic Effect of Rhamnolipids and Inoculation on the Bioremediation of Petroleum-Contaminated Soils by Bacterial Consortia.

Crude oil is a serious soil pollutant, requiring large-scale remediation efforts. Bacterial consortia in combination with rhamnolipids can be an effective bioremediation method. However, the underlying mechanisms and associated changes in soil bacterial composition remain uncharacterized. Therefore, this study sought to evaluate the effectiveness of rhamnolipids in petroleum hydrocarbon removal, and the associated bacterial community dynamics during bioremediation of petroleum-contaminated soils. Contaminated soils were subjected to natural attenuation, bioremediation with rhamnolipids, bioremediation with bacterial consortia, or bioremediation with bacterial consortia supplemented with rhamnolipids (BMR). High-throughput sequencing of bacterial sample partial 16S rRNA sequences was performed. Additionally, the n-alkanes and aromatic fractions were analyzed by gas chromatography-mass spectroscopy. The results showed that rhamnolipid supplementation increased the rate and extent of total petroleum hydrocarbon biodegradation to a maximum of 81% within 35days. Further, phylogenetic analysis revealed that the bacterial community was composed of 14 phylotypes (similarity level = 97%). Actinobacteria and Proteobacteria were the two core phyla in all samples, accounting for 63-89%, but Proteobacteria was the most dominant phylum in the BMR sample (~ 53%). Among the top 20 genera, Pseudomonas, Pseudoxanthomonas, Cavicella, Mycobacterium, Rhizobium, and Acinetobacter were more abundant in BMR samples compared to other samples. Predicted functional profiles revealed that rhamnolipid addition also induced changes in gene abundance related to hydrocarbon metabolic pathways. This study provided comprehensive insights into the synergistic effect of rhamnolipids and bacterial consortia for altering bacterial populations and specific functional traits, which may serve to improve bacteria-mediated petroleum hydrocarbon biodegradation in contaminated soils.

Phormidium Improves Seed Germination and Growth Parameters of Trifolium alexandrinum in Hexadecane-contaminated Soil

Petroleum is known as the main source of fuel and one of the most important environmental pollutants. Petroleum contaminated soil negatively influences plant growth and human health. Bioremediation of petroleum-contaminated soil could be achieved by adding cyanobacteria and photosynthetic microalgae in the soil. In the current study, the beneficial effects of cyanobacterium Phormidium sp. ISC108 treatment on seed germination and plant growth parameters were investigated on berseem clover plants exposed to 1% hexadecane- contaminated soil. For this purpose, after cultivation of berseem clover seeds in soil with 0 and 1% hexadecane, they were irrigated every two days by 3 ml Phormidium (OD600 = 0.7) and water for the cyanobacteria treatment and control, respectively. After 30 days, the biodegradability of hexadecane in the soil around the root was measured by gas chromatography mass-spectrometry (GC-MS). The results showed that Phormidium treatment accelerated germination of berseem clover seeds in both control and hexadecane- contaminated soil. Improvement of plant growth indices such as leaf area, plant fresh weight and leaf RWC due to cyanobacteria treatment was observed in hexadecane-contaminated soil. Hexadecane levels in the soil around the root of the plants irrigated by cyanobacteria were significantly decreased. In addition, the hexadecane degradation in the soil around the roots of berseem clover plant was increased in both control (water) treatment. In conclusion, due to positive effects of Phormidium treatment on seed germination, plant growth of berseem clover and hexadecane degradation, it can be effectively used to enhance plant capacity to cope with hexadecane toxicity in petroleum-contaminated soils.

Study of microbial combination and nutrients in remediation of petroleum-contaminated soil

In this study, degradation of polluted soil (with 1, 4 and 9% petroleum contamination) was performed using different microbial combinations and nutrients. Biosurfactant production and lipase production of the isolated microbes were also tested. A5 and A14 (isolated from petroleum-contaminated soil (PCS)) and G1 and G6 (isolated from garden soil) showed a positive result in the biosurfactant production test. A1, A5, A6, A13, A14, A15, A16, G1 and G5 showed zones around agar wells; these bacterial strains produced lipase. Combinations of microbes were applied in treatment of 1% PCS; the combination of only bacteria and the combination of bacteria and fungi showed petroleum degradation of 71 and 73·17%, respectively. In 4 and 9% PCS, the degradation activities of microbes decreased; the microbes needed a longer time to activate the large amount of petroleum. Furthermore, tests with and without nutrients were conducted to determine the effect of using nutrients in bioremediation of PCS. The results showed that petroleum degradation percentages from the treatment using nutrients were about 5% higher than the degradation percentages from treatments without nutrients.

Bioremediation of petroleum-contaminated soils using Streptomyces sp. Hlh1

Fil: Baoune, Hafida. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universite Kasdi Merbah Ouragla; Argelia

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.

Bioremediation of petroleum-contaminated soil: A Review

Petroleum is the major source of energy for various industries and daily life. Releasing petroleum into the environment whether accidentally or due to human activities is a main cause of soil pollution. Soil contaminated with petroleum has a serious hazard to human health and causes environmental problems as well. Petroleum pollutants, mainly hydrocarbon, are classified as priority pollutants. The application of microorganisms or microbial processes to remove or degrade contaminants from soil is called bioremediation. This microbiological decontamination is claimed to be an efficient, economic and versatile alternative to physicochemical treatment. This article presents an overview about bioremediation of petroleum-contaminated soil. It also includes an explanation about the types of bioremediation technologies as well as the processes.

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.

Evaluation of microbial population and functional genes during the bioremediation of petroleum-contaminated soil as an effective monitoring approach

This study investigated the abundance and diversity of soil n-alkane and polycyclic aromatic hydrocarbon (PAH)-degrading bacterial communities. It also investigated the quantity of the functional genes, the occurrence of horizontal gene transfer (HGT) in the identified bacterial communities and the effect that such HGT can have on biostimulation process. Illumina sequencing was used to detect the microbial diversity of petroleum-polluted soil prior to the biostimulation process, and quantitative real-time PCR was used to determine changes in the bacterial community and functional genes (alkB, phnAc and nah) expressions throughout the biostimulation of petroleum-contaminated soil. The illumine results revealed that γ-proteobacteria, Chloroflexi, Firmicutes, and δ-proteobacteria were the most dominant bacterial phyla in the contaminated site, and that most of the strains were Gram-negative. The results of the gene expression results revealed that gram-negative bacteria and alkB are critical to successful bioremediation. Failure to maintain the stability of hydrocarbon-degrading bacteria and functional gene will reduce the extend to which alkanes and PAHs are degraded. According to the results of the study, the application of a C:N:P ratio of was 100:15:1 in the biodegradation experiment resulted in the highest rate at which petroleum hydrocarbons were biodegraded. The diversity of pollutant-degrading bacteria and the effective transfer of degrading genes among resident microorganisms are essential factors for the successful biostimulation of petroleum hydrocarbons. As such, screening these factors throughout the biostimulation process represents an effective monitoring approach by which the success of the biostimulation can be assessed.

Bioremediation of petroleum-contaminated soil by a combined system of biostimulation–bioaugmentation with yeast

This paper presents a study of the effect of a combined biostimulation–bioaugmentation treatment applied to a clay-loam soil contaminated with 16,300 mg/kg of total petroleum hydrocarbons (TPH), which comprised 51% saturated hydrocarbons and 31% aromatic hydrocarbons. The bioaugmentation was performed with yeast Candida tropicalis SK21 isolated from petroleum-contaminated soil. The strain was able to grow in a pH range of 3–9 in liquid culture, and the optimum pH was found to be 6 for both growth and biosurfactant production. At pH 6, 96% and 42% of TPH were degraded by the strain at the initial diesel oil concentrations of 0.5% and 5% (v/v), respectively. The remediation via inoculating the yeast removed 83% of TPH in 180 days while the experiment with the indigenous microorganisms alone removed 61%. Microbial enumeration showed that the yeast SK21 could grow good in the soil. It was also found that dehydrogenase and polyphenoloxidase activities in soil were remarkably enhanced by the inoculation of the yeast.

Bioremediation of petroleum-contaminated soil by biostimulation amended with biochar

In this study, the effects of rice straw biochar on soil contaminant biodegradation and microbial community compositions were investigated in the laboratory during a 180-day period. The results of soil microcosm experiments showed that contaminant degradation efficiency was significantly higher in soils amended with biochar than in soils without. The adding time of biochar had apparent effects on degradation efficiency. The removal efficiencies of total petroleum hydrocarbons (TPH) were 61.2%, 77.8% and 84.8%, in the soils without biochar, amended with biochar at the beginning or the 80th day respectively. When adding biochar at the 80th day, the TPH concentration decreased to below the threshold level required for Chinese soil quality for TPH (3000 mg kg−1 dry weight) in 140 days. The addition of biochar did not result in appreciable negative impacts on soil microbial community composition. It was speculated that when adding biochar at the 80th day, a large amount of metabolites could be absorbed onto the biochar, leading to significant reduction in soil toxicity and biodegradation enhancement.

POTENTIAL OF GLYCEROL AND SOYBEAN OIL FOR BIOREMEDIATION OF WEATHERED OILY-SLUDGE CONTAMINATED SOIL

The bioremediation of petroleum-contaminated soil was investigated on laboratory scale. This work evaluated the effect of co-substrate addition in tropical climate soil highly contaminated with oily residue. Glycerol and soybean oil were used as auxiliary co-substrates for contaminant degradation. Three different concentrations of co-substrate were tested, and the experiments were carried out over 60 days. The following parameters were monitored: humidity, pH, total heterotrophic bacteria, total fungi, total petroleum hydrocarbons (TPH), and the concentrations of benzo[a]pyrene and chrysene. The soil supplementation with renewable co-substrates improved the efficiency of the biodegradation TPH, with removals of 85% and 83% for glycerol and soybean oil, respectively, compared to a 55% removal yielded by the biodegradation process without supplementation. The use of glycerol increased Chrysene and Benzo[a]pyrene biodegradation by 50%, while soybean oil supplementation increased their removal by 36%.