Removal of polycyclic aromatic hydrocarbons from soil using surfactant and the white rot fungus Phanerochaete chrysosporium

The bioremediation of soil contaminated with polycyclic aromatic hydrocarbons (PAH) is often limited by a low bioavailability of the contaminants. Non‐ionic surfactants, such as Tween 80, when above their critical micelle concentration (CMC), can efficiently enhance the bioavailability of PAHs in contaminated soil by increasing solubility and dissolution rates. However, disposing of this micelle‐contaminated spent washwater can be a major problem. The aim of this study was to combine surfactant soil washing techniques using Tween 80 with the versatile lignin‐degrading system of the white rot fungus, Phanerochaete chrysosporium, to bioremediate PAH‐contaminated soil. Approximately 85% (w/w) of a total of nine PAHs in an aged (1 month) contaminated soil (total PAH concentration = 403.61 µg g⁻¹) could be solubilized in a 2.5% (w/v) Tween 80 solution at a soil/water ratio of 1:10. The washwater was then catabolized by a 3‐day‐old culture of P chrysosporium under a stationary condition. The disappearance of most PAHs tested (molecular weight ≥ 178) correlated well with their ionization potentials and 66.4% (w/w) of the total PAHs in washwater with 2.5% (w/v) Tween 80 was catabolized after 11 days of culture. The catabolism was enhanced to 86% (w/w) using a lower concentration of 0.5% (w/v) Tween 80. The initial oxidation rate of total PAHs based on the first 4 days of culture remained almost constant at approximately 1.88 µg cm⁻³day⁻¹ when the Tween 80 concentration in washwater was increased from 0.5% to 2.5% (w/v). The combination of soil washing and white rot fungus catabolization of PAH using 2.5% (w/v) Tween 80 eliminated the total PAH concentration in the contaminated soil by 56.4% (w/w) after 11 days. The results suggest that PAH‐contaminated soil may be cleansed by using a combination of surfactant soil washing and white rot fungus catabolism. © 2000 Society of Chemical Industry     

Effect of non‐ionic surfactants on elimination of polycyclic aromatic hydrocarbons (PAHs) in soil‐slurry by Phanerochaete chrysosporium

Surfactants can enhance bioremediation of soil contaminated with polycyclic aromatic hydrocarbons (PAHs) by increasing their bioavailability. The objective of this study was to evaluate the effect of non‐ionic polyoxyethylene (POE) surfactants on the elimination of nine PAHs in contaminated soil by the white rot fungus Phanerochaete chrysosporium. PAHs in both liquid and solid phases were extracted and then assayed using GC–MS. Fungal biomass concentration and the activity of extracellular ligninolytic enzymes were used to determine the toxicity of POE surfactants. Results indicated that 0.5% (w/v) of surfactant Tween 80 was not toxic to fungal growth and had little impact on extracellular ligninolytic enzyme synthesis. About 80% of low ring PAHs (ie acenaphthene and fluorene) could be efficiently catabolized by P chrysosporium without surfactants, while catabolism of others (ie phenanthrene, fluoranthene, pyrene, chrysene, benzo(a)pyrene, dibenz(ah)anthracene and benzo(ghi)perylene) was less than 30% over a 8‐day culture period. Elimination of four‐to six‐ring PAHs in contaminated soil was enhanced in P chrysosporium cultures with 0.4% (w/v) Tween 80 by 15–33% compared with those in cultures without Tween 80, while no obvious effect was observed in the elimination of three‐ring PAHs over the culture period. Investigations on PAH concentrations in aqueous phase during the culture period showed that Tween 80 increased PAH aqueous concentrations and the PAH oxidation rate in aqueous was rapid. Enhancement of soil PAH elimination in the presence of Tween 80 was due to the increased PAH bioavailability. © 2001 Society of Chemical Industry     

Extent of cleaning achievable by bioremediation of soil contaminated with petrochemical sludges

Bioremediation is capable of reducing the hydrocarbon concentration of contaminated soil by 75–95% depending on the soil type, the kind of hydrocarbons and the history of the contamination. The impact of different number of petrochemical sludge applications to soil on the degree of PAH elimination was assessed. A simple and reliable extraction and gas chromatographic method was used to facilitate more rapid determination of hydrocarbon contamination in soils and sludge wastes. Its application in a model laboratory bioremediation experiment and a pilot field study were used to illustrate its practical benefits. Post-remediation persistence of sludge constituents was evaluated after a single dose sludge application in the laboratory and after seven sludge applications in the field. A relative increase in the concentration of some PAHs was detected at the end of the experiments, but their individual concentrations were reduced to suggested values for industrial soils. The remaining concentration of total hydrocarbons in soil was found to be similar in both experiments, pointing to soil organic matter adsorption capacity as the factor determining hydrocarbon elimination limits in soil bioremediation. ©1997 SCI     

Microbial Degradation of High Molecular Weight Polycyclic Aromatic Hydrocarbons with Emphasis on Pyrene

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) is a major concern in the environment due to their toxic nature and ubiquitous occurrence. PAHs remain sorbed to soil organics and interact with non-aqueous phases and therefore, become less available for degradation. Several microorganisms like bacteria, fungi, and algae have the capability to degrade soil-sorbed PAHs using different metabolic pathways. The focus of this review is microbial degradation of high molecular weight PAH pyrene by pure and mixed culture, including biological aspects of biosurfactants produced during the process for increasing the bioavailability of soil-sorbed or non-aqueous phase pyrene. High molecular weight PAHs are generally recalcitrant to microbial attack, although some bacteria, fungi, and algae are capable of transforming these compounds by using them as the sole source of carbon and energy. Also, the use of microbial consortium has been found to be more efficient and better from an economic point of view for degradation due to synergistic interactions among microbial species. The review also explains the role of catabolic genes involved in the degradation of pyrene.     

Treatment of PAH‐contaminated soil by combination of Fenton's reaction and biodegradation

A combination of modified Fenton and biological treatment was used to remove polycyclic aromatic hydrocarbons (PAHs) from creosote oil‐contaminated soil. After modified Fenton reaction the toxicity of column leachate and soil to Vibrio fischeri increased. The number of intact bacterial cells and utilisation of PAHs in PAH utilisation microplate assay decreased after modified Fenton reaction. However, bacteria in chemically treated soil utilised PAHs without addition of other carbon sources. The activity of extracellular esterases increased during incubation of modified Fenton‐treated soil. PAH removal in combined chemical oxidation and incubation (43–59%) was higher than in incubation alone (22–30%). Residual H₂O₂ in soil allowed chemical oxidation of PAHs during incubation. Copyright © 2006 Society of Chemical Industry     

Reduction of petroleum hydrocarbons content from an engine oil refinery wastewater using a continuous stirred tank reactor monitored by spectrometry tools

BACKROUND: Hydrocarbon contamination of groundwater resources has become a major environmental and human health concern in many parts of the world. Microbial degradation of hydrocarbons, through either naturally occurring processes or engineered systems, has been successfully used to reduce concentrations of these pollutants. In order to develop an aerobic bioreactor tailored for this purpose, the present study aims to investigate petroleum contaminated wastewater remediation and toxicity reduction by acclimated microbial consortium enriched in a continuous stirred tank bioreactor (CSTR). Characterization and quantification of refinery wastewater components were performed by gas chromatography mass spectrometry (GC/MS) and Fourier transform infrared (FTIR) spectroscopy. RESULTS: The petroleum hydrocarbons were significantly degraded (97%) by the microbial consortium. After continuous aerobic treatment in the CSTR, the COD_effluent and BOD_5effluent average removals were high reaching 97% and 78%, respectively. Also, strong degradation of C10? C35 n‐alkanes was observed. The concomitant use of GC/MS and FTIR proved to be a useful complementary tool to assess the impact of treatment strategies on hydrocarbon‐contaminated wastewater. In addition, the toxicity of the contaminated wastewater decreased drastically after bioremediation. CONCLUSION: This work shows the ability of this consortium to degrade hydrocarbons and reduce toxicity, which makes them useful candidates for environmental restoration applications at other hydrocarbon‐contaminated environments. Copyright © 2011 Society of Chemical Industry     

Sorption-Desorption of Pyrene for Colombia and New Mexico Soils

The adsorption and availability of polycyclic aromatic hydrocarbons (PAHs) in the environment is an important factor to be considered for potential bioremediation processes. If desorption of the organic occurs, it could imply that remediation technologies such as microbial degradation may be feasible for PAH contaminated soils. Conversely no, or partial, desorption would indicate that the components may persist in the environment due to their decreased bioavailability. The sorption-desorption of pyrene in conjunction with two different soils was studied to determine the feasibility of bioremediation as an effective treatment. The measured distribution coefficient (K _d ) for the Colombia and New Mexico soils using a 4:40 soil:liquid ratio was 1956 and 526 L/kg, respectively. When the soil:liquid ratio was reduced to 1:40, the K _d values were 4294 L/Kg for the Colombia, and 1141 L/Kg for the New Mexico soil.     

Evaluation of drum bioreactor performance used for decontamination of soil polluted with polycyclic aromatic hydrocarbons

A laboratory‐scale drum bioreactor system was used to study engineering aspects of soil bioremediation. Polycyclic aromatic hydrocarbons (PAHs) were chosen as contaminants in soil. In the operation of the reactor, different mixing strategies were applied according to the size of soil without separate washing of sand. The effect of the water content of the soil mixture on solid mixing time and phenanthrene degradation rate was of particular interest. At 20% water content, which was below the saturation level, the mixing efficiency of soil and the degradation rate of phenanthrene was lower than those at 30% or 40% water content. Optimal water content was variable according to the soil texture. The drum bioreactor was operated under optimal water content and PAH concentration (fluorene, phenanthrene, anthracene, pyrene) and microbial numbers were measured in each soil phase (sediment and suspension). Over 95% of PAHs with three or four rings (fluorene, phenanthrene, anthracene, pyrene) were degraded at 270 mg kg⁻¹ soil within 20 days. The degradation rate of PAHs in the suspension phase was higher than that in sediment phase. © 1999 Society of Chemical Industry     

Enhanced bioremediation of crude oil‐contaminated soil by a Pseudomonas species and mutually associated adapted Azotobacter vinelandii

A mixed culture of compatible hydrocarbonoclastic and diazotrophic bacteria, each at a density of 10⁸ organisms cm^?3, was developed for optimised bioremediation of crude oil‐contaminated soil. The hydrocarbonoclastic bacterium, Pseudomonas sp and the diazotroph, Azotobacter vinelandii, were both isolated from a previously crude oil‐contaminated soil and thereafter modelled as a unit of mutualistic consortium in situ. Stabilisation of the consortium and hence the optimised bioremediation process occurred when the bacterial growth attained a pseudo‐steady state condition. This was considered to be as a result of a symbiotic association between A vinelandii and the Pseudomonas sp in which A vinelandii produced the required concentration of fixed nitrogen compounds required for the growth of the Pseudomonas sp. Enhancement in biodegradation, due to stimulated growth of Pseudomonas sp and co‐metabolic activity of A vinelandii, was mathematically evaluated as the difference in the specific growth rates (µ) between the consortium Pseudomonas sp/A vinelandii and Pseudomonas sp alone. The proportion of petroleum hydrocarbons degraded by the consortium from the contaminated soil ranged between 66.83 and 69.6% as compared with that of a pure culture of Pseudomonas sp (23.2–44.45%). Hence, beyond their role in biological nitrogen fixation, diazotrophs may be used to contribute to bioremediation of crude oil‐contaminated land. Copyright © 2004 Society of Chemical Industry     

The Effect of Polycyclic Aromatic Hydrocarbons on the Structure of Organotrophic Bacteria and Dehydrogenase Activity in Soil

The objective of this article was to determine the structure of microbial communities and the activity of dehydrogenases in soil samples contaminated with four polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, phenanthrene, anthracene, and pyrene, in the amount of 0, 1000, 2000, and 4000 mg kg^?1soil DM. Organic substances—cellulose, sucrose, and compost—were added to the samples in the amount of 0 and 9 g kg^?1soil DM. The experiment was performed in a laboratory on samples of loamy sand. Indices of colony development (CD) and eco-physiological diversity (EP) of organotrophic bacteria, soil resistance (RS), and soil resilience (RL) were calculated. Soil contamination with PAHs differentiated the structure of organotrophic bacteria, and the lowest CD and EP values were noted in soil samples containing pyrene. PAHs inhibited the activity of dehydrogenases, and pyrene exerted the most inhibitory effect on enzyme activity. Dehydrogenase activity was determined mainly by the applied PAH dose, the date of analysis and the type of organic substance added to soil. Low RL values indicate that exposure to PAHs induces long-term changes in dehydrogenase activity.     

Effects of Secondary Plant Metabolites on Microbial Populations: Changes in Community Structure and Metabolic Activity in Contaminated Environments

Secondary plant metabolites (SPMEs) play an important role in plant survival in the environment and serve to establish ecological relationships between plants and other organisms. Communication between plants and microorganisms via SPMEs contained in root exudates or derived from litter decomposition is an example of this phenomenon. In this review, the general aspects of rhizodeposition together with the significance of terpenes and phenolic compounds are discussed in detail. We focus specifically on the effect of SPMEs on microbial community structure and metabolic activity in environments contaminated by polychlorinated biphenyls (PCBs) and polyaromatic hydrocarbons (PAHs). Furthermore, a section is devoted to a complex effect of plants and/or their metabolites contained in litter on bioremediation of contaminated sites. New insights are introduced from a study evaluating the effects of SPMEs derived during decomposition of grapefruit peel, lemon peel, and pears on bacterial communities and their ability to degrade PCBs in a long-term contaminated soil. The presented review supports the “secondary compound hypothesis” and demonstrates the potential of SPMEs for increasing the effectiveness of bioremediation processes.     

Aerobic and Anaerobic Bacterial and Fungal Degradation of Pyrene: Mechanism Pathway Including Biochemical Reaction and Catabolic Genes

Microbial biodegradation is one of the acceptable technologies to remediate and control the pollution by polycyclic aromatic hydrocarbon (PAH). Several bacteria, fungi, and cyanobacteria strains have been isolated and used for bioremediation purpose. This review paper is intended to provide key information on the various steps and actors involved in the bacterial and fungal aerobic and anaerobic degradation of pyrene, a high molecular weight PAH, including catabolic genes and enzymes, in order to expand our understanding on pyrene degradation. The aerobic degradation pathway by Mycobacterium vanbaalenii PRY-1 and Mycobactetrium sp. KMS and the anaerobic one, by the facultative bacteria anaerobe Pseudomonas sp. JP1 and Klebsiella sp. LZ6 are reviewed and presented, to describe the complete and integrated degradation mechanism pathway of pyrene. The different microbial strains with the ability to degrade pyrene are listed, and the degradation of pyrene by consortium is also discussed. The future studies on the anaerobic degradation of pyrene would be a great initiative to understand and address the degradation mechanism pathway, since, although some strains are identified to degrade pyrene in reduced or total absence of oxygen, the degradation pathway of more than 90% remains unclear and incomplete. Additionally, the present review recommends the use of the combination of various strains of anaerobic fungi and a fungi consortium and anaerobic bacteria to achieve maximum efficiency of the pyrene biodegradation mechanism.     

Analysis of Polycyclic Aromatic Compounds in Soil Samples Using Laser-Induced Phosphorimetry

Abstract

The analysis and spectral characteristics of several polycyclic aromatic hydrocarbons (PAHs) have been investigated by Laser-Induced Solid-Surface Room Temperature Phosphorimetry (LI-SSRTP). These PAHs included phenanthrene, chrysene, 1,2 benzofluorene, 2,3 benzofluorene, pyrene, coronene, 1,2,3,4 dibenzanthracene, benzo(a)pyrene, benzo(e)pyrene, and benzo(g, h, i)perylene. A nitrogen laser was employed as the excitation source at 337 nm. Filter paper treated with UV irradiation for background reduction was used as the solid substrate. Thallium(I)acetate was employed as a phosphorescence enhancer. Absolute limits of detection in the picogram level were obtained for all the PAHs, improving SSRTP levels of detection by three orders of magnitude. Finally, the proposed method was tested with a PAH contaminated soil sample. Detection of several PAHs at the nanogram level was easily performed, showing the potential of LI-SSRTP to the analysis of samples of environmental concern.     

Levels of Polycyclic Aromatic Hydrocarbons (PAHs) in Atmospheric Environment of Urban Areas in Latin America

Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds considered as pollutants of high priority due to their carcinogenic potential. PAH can appear in water, soil or in the atmosphere as adsorbed on particulate material or in gas phase. An increased number of studies on atmospheric PAH in urban areas have been published in the last decade, especially in the last years. Anthropogenic sources are frequently mentioned to be responsible for the increased concentration of PAHs in the atmosphere of urban areas, which at the same time seems to depend on meteorological parameters. This research is focused on compiling information on PAH levels in Latin America and their relationship with typical meteorological variables from seasonal and tropical countries. Brazil is the country with the most number of bibliographies about this topic, followed by Argentina, Chile and Mexico. Scarce information was found for Colombia and Venezuela and none for the rest of Latin American countries. The majority of studies checked have evaluated the climatological parameters in relationship with the PAH concentration and their distribution, finding that it affects meaningfully their levels. The monitor campaigns in Brazil have been developed mainly in the southern cities, where PAHs are strongly influenced by the seasons and their proximity to the South Pole. Tropical countries such as Venezuela and Colombia showed moderate variation of PAH concentration through months. The main influential parameters are precipitation and direction/speed winds.     

Bioremediation of polycyclic aromatic hydrocarbons: current knowledge and future directions

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds that have accumulated in the natural environment mainly as a result of anthropogenic activities such as the combustion of fossil fuels. Interest has surrounded the occurrence and distribution of PAHs for many decades due to their potentially harmful effects to human health. This concern has prompted researchers to address ways to detoxify/remove these organic compounds from the natural environment. Bioremediation is one approach that has been used to remediate contaminated land and waters, and promotes the natural attenuation of the contaminants using the in situ microbial community of the site. This review discusses the variety of fungi and bacteria that are capable of these transformations, describes the major aerobic and anaerobic breakdown pathways, and highlights some of the bioremediation technologies that are currently available. Copyright © 2005 Society of Chemical Industry     

THE FATE AND BEHAVIOR OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) THROUGH FEEDING AND EXCRETION OF ANNELIDS

The concentration of polycyclic aromatic hydrocarbons (PAHs) in sediment and excrements of annelids was measured by gas chromatography-mass spectrometry (GC/MS) and the movement of PAHs in the tidal flat was investigated. The PAH concentrations ranged 4.4–80.4 and 61.2–286.9 μg/kg-dry for the excrement of Arenicola basiliensis and of Marphysa sanguinea, respectively; the former contained about 10 times as much PAHs as the sediment and the latter about 100 times. The difference in the PAH concentration between the two organisms was attributed to their feeding behavior; M. sanguinea intakes much more detritus containing PAHs than A. basiliensis. Moreover, after the excrement of M. sanguinea had stood on the sediment for 2 hours, the PAH concentrations decreased to half. The reduction of the PAHs may arise from chemical changes owing to microorganisms and/or enzymes in the excrement of M. sanguinea.     

Effect of vegetable oil addition on bioaccessibility and biodegradation of polycyclic aromatic hydrocarbons in historically contaminated soils

BACKGROUND: Bioaccessibility is often the limiting factor for the biodegradation of polycyclic aromatic hydrocarbons (PAH) in soils. The present study explores the potential of amending canola oil, an economically and ecologically attractive soil additive, for the enhancement of bioaccessibility and, in consequence, biodegradation of PAH in historically contaminated, bioaccessibility limited soils. RESULTS: The amendment of canola oil (1% and 5%, w/w) to contaminated soils increased the bioaccessibility and the subsequent biodegradation of PAH with up to four rings. Residual concentrations of pyrene and fluoranthene in oil‐treated soils were 38–53% lower compared to the unamended tests. The continuous removal of bioaccessible PAH with a passive sampling system confirmed that oil amendment indeed increased bioaccessibility, leading to a lower non‐accessible PAH fraction. Canola oil amendment did, by contrast, not increase the bioaccessibility of high molecular weight PAH, likely due to their strong binding to soil organic carbon compounds. CONCLUSION: Canola oil can be used efficiently in low concentrations to render PAH up to four rings accessible for biodegradation in historically contaminated soils. Contaminants remaining in soil after treatment may pose a significantly lowered environmental risk, as is indicated by the lack of mobilisation by a solubilising agent such as canola oil. Copyright © 2009 Society of Chemical Industry     

Isolation and Characterization of Phenanthrene-Degrading Bacteria from PAHs Contaminated Mangrove Sediment of Thane Creek in Mumbai,India

Polycyclic aromatic hydrocarbons (PAHs), including phenanthrene, are commonly found as pollutants in soils, estuarine, and sediments, as well as in terrestrial and other aquatic ecosystems. In this context, the phenanthrene-degrading bacteria were isolated and characterized in contaminated mangrove surface sediment, on the coast of Thane Creek, Mumbai, India by enrichment method, using phenanthrene as the sole source of carbon and energy. The phylogenetic diversity of the isolates were evaluated by 16S rRNA gene analysis and characterized as Bacillus mojavensis strain KSS001, Bacillus firmus strain KSS002, Bacillus flexus strain KSS003, Bacillus vietnamensis strain KSS004, and Bacillus amyloliquefaciens strain KSS005. Each isolate was grown on the phenanthrene up to 100 mg/L and the biodegradation ability was evidenced using a gas chromatography–flame ionization detector. Further, the mean value of phenanthrene degradation by 5 bacterial isolates after incubation in mineral salt medium for 7 days was 63% at 100 mg/L. The study reports that mangrove sediments of Thane Creek, Mumbai, contain a diverse population of phenanthrene-degrading bacteria that have the potential and capability to degrade PAHs contaminated sites, and are consequently recommended for bioremediation.     

Effect of Bioaugmentation by Bacterial Consortium and Methyl-β-cyclodextrin on Soil Functional Diversity and Removal of Polycyclic Aromatic Hydrocarbons

ABSTRACT

The low biological effectiveness of polycyclic aromatic hydrocarbons (PAHs) is the main limiting factor of in-situ bioremediation of PAH-contaminated soil. The purpose of the present study was to assess the effects of methyl-β-cyclodextrin (MCD) and microbial consortia on the PAHs degradation rate and microbial ecology and functional diversity and stability in soil. The results show that MCD and microorganisms significantly increased the degradation rate of pyrene and benzo[a]pyrene by 30.1% and 9.1%, respectively, (p < 0.05) after 4 weeks. The average well color development (AWCD) values and diversity indices of bioaugmentation (B) and MCD- and bacterial-assisted bioaugmentation (MB) were significantly higher than that in control (CK). The Shannon–Weaver index (H) and McIntosh index (U) in the MB treatment were significantly higher than those observed in other treatments, which indicated that its species richness and individuals were distributed evenly. The soil microbial activity and community structure were the most abundant in the MB treatment. Compared to the CK treatment, MB significantly promoted soil dehydrogenase activity (DHA) and fluorescein diacetate hydrolysis (FDAH) enzyme activity, which were increased by 96.3% and 994.3%, respectively. According to the results of principal component analysis, the physiological functions of microbial communities in the MB and B treatments were different from the other treatments. Therefore, the combination of the microorganisms with MCD can stimulate the remediation efficiency of PAHs and the physiological functions of microbial communities.     

Biosurfactant-Assisted Bioremediation of Polycyclic Aromatic Hydrocarbons (PAHs) in Liquid Culture System and Substrate Interactions

A lipopeptide biosurfactant was produced by the bacterium Pseudomonas aeruginosa strain LBP9 isolated from petroleum-contaminated soil. Phenanthrene, fluoranthene, and pyrene were used as model polycyclic aromatic hydrocarbons (PAHs) to study the effect of the biosurfactant on the biodegradation of mixed and sole substrate PAHs, and examine substrate interactivity effects on their biodegradation in liquid culture. At 400 mg/L amendment of lipopeptide, the solubility of phenanthrene, fluoranthene, and pyrene were increased to 19, 33, and 45 times their aqueous solubility, respectively, and the extent of substrate utilization rate (q_max?) of PAHs was enhanced up to three-fold in the sole substrate studies in comparison to the unamended controls. In the ternary PAH mixture at total concentration of 300 mg/L, with equal parts of each PAH, 77%, 57%, and 33% degradation of phenanthrene, fluoranthene, and pyrene were observed, respectively, at 400 mg/L lipopeptide amendment on day 30 of incubation. Whereas in the sole substrate experiments at 300 mg/L concentration of each PAH and the same level of lipopeptide amendment more than 98% fluoranthene and 76% pyrene were degraded and phenanthrene removal was so rapid that at day 4 of incubation more than 80% was degraded. Biosurfactants at optimum amounts enhanced biodegradation of PAHs. Lipopeptide amendments of 200 mg/L and 400 mg/L were found out to be optimum amounts for statistically significant (p < 0.05) biodegradation of the PAHs in the experiments. However, despite biosurfactant-enhanced bioavailability of the PAHs, biodegradation rate was competitively inhibited in the multisubstrate microcosms.