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Special Issue "Biodegradation of Conventional and Emerging Pollutants"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Green Chemistry".

Deadline for manuscript submissions: closed (31 December 2019).

Special Issue Editors

Dr. Łukasz Chrzanowski
E-Mail Website
Guest Editor
Faculty of Chemical Technology, Poznan University of Technology, Berdychowo 4, 60-965 Poznań, Poland
Interests: microbial degradation of petroleum hydrocarbons and ionic liquids; (bio)surfactant-mediated biodegradation; microbiological aspect of biodiesel as a fuel additive; mechanisms of bacterial adaptation to toxic xenobiotics, novel herbicidal ionic liquids
Special Issues and Collections in MDPI journals
Dr. Łukasz Ławniczak
E-Mail Website
Guest Editor
Faculty of Chemical Technology, Poznan University of Technology, Berdychowo 4, 60-965 Poznań, Poland
Interests: environmental impact of organic compounds; biodegradation processes; biosurfactants; industrial pollutants
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

Our first steps into the 21st century are associated with the introduction of ground-breaking technological advances; however, this progress often comes at the cost of notable environmental hazards. The development of numerous industrial sectors has resulted in the production of several novel compounds, such as pharmaceuticals, pesticides, and various chemical additives. These groups often include xenobiotics with an unknown environmental impact. Furthermore, the growing population of consumers corresponds to increased usage of personal care products. This leads to constant use of surfactants, polymers, and organic solvents. Our economy is currently facing an important shift from nonrenewable resources to sustainability; therefore, the contamination with petroleum hydrocarbons as well as heavy metal ions still remains a topic of high importance. Despite the improvement of environmental awareness, chemical compounds are continuously released into the environment, and chronic exposure to low doses of pollutants has been recognized as a major health threat. In order to counter the abovementioned issues, there is an urgent need to provide appropriate analytical, technical, and legal solutions.

As such, this Special Issue is focused on the identification of conventional and emerging pollutants as well as the description of monitoring and treatment methods. The challenge to make chemistry “green” still remains valid.

Dr. Lukasz Chrzanowski
Dr. Łukasz Ławniczak
Guest Editors

Manuscript Submission Information

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Keywords

  • Organic pollutants
  • Inorganic pollutants
  • Environmental monitoring
  • Bioremediation

Published Papers (12 papers)

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Research

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Open AccessArticle
Enhanced Degradation of Naproxen by Immobilization of Bacillus thuringiensis B1(2015b) on Loofah Sponge
Molecules 2020, 25(4), 872; https://doi.org/10.3390/molecules25040872 (registering DOI) - 17 Feb 2020
Abstract
The naproxen-degrading bacterium Bacillus thuringiensis B1(2015b) was immobilised onto loofah sponge and introduced into lab-scale trickling filters. The trickling filters constructed for this study additionally contained stabilised microflora from a functioning wastewater treatment plant to assess the behavior of introduced immobilized biocatalyst in [...] Read more.
The naproxen-degrading bacterium Bacillus thuringiensis B1(2015b) was immobilised onto loofah sponge and introduced into lab-scale trickling filters. The trickling filters constructed for this study additionally contained stabilised microflora from a functioning wastewater treatment plant to assess the behavior of introduced immobilized biocatalyst in a fully functioning bioremediation system. The immobilised cells degraded naproxen (1 mg/L) faster in the presence of autochthonous microflora than in a monoculture trickling filter. There was also abundant colonization of the loofah sponges by the microorganisms from the system. Analysis of the influence of an acute, short-term naproxen exposure on the indigenous community revealed a significant drop in its diversity and qualitative composition. Bioaugmentation was also not neutral to the microflora. Introducing a new microorganism and increasing the removal of the pollutant caused changes in the microbial community structure and species composition. The incorporation of the immobilised B1(2015b) was successful and the introduced strain colonized the basic carrier in the trickling filter after the complete biodegradation of the naproxen. As a result, the bioremediation system could potentially be used to biodegrade naproxen in the future. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessArticle
Assessment of Biodegradation Efficiency of Polychlorinated Biphenyls (PCBs) and Petroleum Hydrocarbons (TPH) in Soil Using Three Individual Bacterial Strains and Their Mixed Culture
Molecules 2020, 25(3), 709; https://doi.org/10.3390/molecules25030709 - 06 Feb 2020
Abstract
Biodegradation is one of the most effective and profitable methods for the elimination of toxic polychlorinated biphenyls (PCBs) and total petroleum hydrocarbons (TPH) from the environment. In this study, aerobic degradation of the mentioned pollutants by bacterial strains Mycolicibacterium frederiksbergense IN53, Rhodococcus erythropolis [...] Read more.
Biodegradation is one of the most effective and profitable methods for the elimination of toxic polychlorinated biphenyls (PCBs) and total petroleum hydrocarbons (TPH) from the environment. In this study, aerobic degradation of the mentioned pollutants by bacterial strains Mycolicibacterium frederiksbergense IN53, Rhodococcus erythropolis IN129, and Rhodococcus sp. IN306 and mixed culture M1 developed based on those strains at 1:1:1 ratio was analyzed. The effectiveness of individual strains and of the mixed culture was assessed based on carried out respirometric tests and chromatographic analyses. The Rhodococcus sp. IN306 turned out most effective in terms of 18 PCB congeners biodegradation (54.4%). The biodegradation index was decreasing with an increasing number of chlorine atoms in a molecule. Instead, the Mycolicobacterium frederiksbergense IN53 was the best TPH degrader (37.2%). In a sterile soil, contaminated with PCBs and TPH, the highest biodegradation effectiveness was obtained using inoculation with mixed culture M1, which allowed to reduce both the PCBs (51.8%) and TPH (34.6%) content. The PCBs and TPH biodegradation capacity of the defined mixed culture M1 was verified ex-situ with prism method in a non-sterile soil polluted with aged petroleum hydrocarbons (TPH) and spent transformer oil (PCBs). After inoculation with mixed culture M1, the PCBs were reduced during 6 months by 84.5% and TPH by 70.8% as well as soil toxicity was decreased. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessArticle
Hydrocarbon Removal by Two Differently Developed Microbial Inoculants and Comparing Their Actions with Biostimulation Treatment
Molecules 2020, 25(3), 661; https://doi.org/10.3390/molecules25030661 - 04 Feb 2020
Abstract
Bioremediation of soils polluted with petroleum compounds is a widely accepted environmental technology. We compared the effects of biostimulation and bioaugmentation of soil historically contaminated with aliphatic and polycyclic aromatic hydrocarbons. The studied bioaugmentation treatments comprised of the introduction of differently developed microbial [...] Read more.
Bioremediation of soils polluted with petroleum compounds is a widely accepted environmental technology. We compared the effects of biostimulation and bioaugmentation of soil historically contaminated with aliphatic and polycyclic aromatic hydrocarbons. The studied bioaugmentation treatments comprised of the introduction of differently developed microbial inoculants, namely: an isolated hydrocarbon-degrading community C1 (undefined—consisting of randomly chosen degraders) and a mixed culture C2 (consisting of seven strains with well-characterized enhanced hydrocarbon-degrading capabilities). Sixty days of remedial treatments resulted in a substantial decrease in total aliphatic hydrocarbon content; however, the action of both inoculants gave a significantly better effect than nutrient amendments (a 69.7% decrease for C1 and 86.8% for C2 vs. 34.9% for biostimulation). The bioaugmentation resulted also in PAH removal, and, again, C2 degraded contaminants more efficiently than C1 (reductions of 85.2% and 64.5%, respectively), while biostimulation itself gave no significant results. Various bioassays applying different organisms (the bacterium Vibrio fischeri, the plants Sorghum saccharatum, Lepidium sativum, and Sinapis alba, and the ostracod Heterocypris incongruens) and Ames test were used to assess, respectively, potential toxicity and mutagenicity risk after bioremediation. Each treatment improved soil quality, however only bioaugmentation with the C2 treatment decreased both toxicity and mutagenicity most efficiently. Illumina high-throughput sequencing revealed the lack of (C1) or limited (C2) ability of the introduced degraders to sustain competition from indigenous microbiota after a 60-day bioremediation process. Thus, bioaugmentation with the bacterial mixed culture C2, made up of identified, hydrocarbon-degrading strains, is clearly a better option for bioremediation purposes when compared to other treatments. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessArticle
Biodegradability of Dental Care Antimicrobial Agents Chlorhexidine and Octenidine by Ligninolytic Fungi
Molecules 2020, 25(2), 400; https://doi.org/10.3390/molecules25020400 - 18 Jan 2020
Abstract
Chlorhexidine (CHX) and octenidine (OCT), antimicrobial compounds used in oral care products (toothpastes and mouthwashes), were recently revealed to interfere with human sex hormone receptor pathways. Experiments employing model organisms—white-rot fungi Irpex lacteus and Pleurotus ostreatus—were carried out in order to investigate [...] Read more.
Chlorhexidine (CHX) and octenidine (OCT), antimicrobial compounds used in oral care products (toothpastes and mouthwashes), were recently revealed to interfere with human sex hormone receptor pathways. Experiments employing model organisms—white-rot fungi Irpex lacteus and Pleurotus ostreatus—were carried out in order to investigate the biodegradability of these endocrine-disrupting compounds and the capability of the fungi and their extracellular enzyme apparatuses to biodegrade CHX and OCT. Up to 70% ± 6% of CHX was eliminated in comparison with a heat-killed control after 21 days of in vivo incubation. An additional in vitro experiment confirmed manganese-dependent peroxidase and laccase are partially responsible for the removal of CHX. Up to 48% ± 7% of OCT was removed in the same in vivo experiment, but the strong sorption of OCT on fungal biomass prevented a clear evaluation of the involvement of the fungi or extracellular enzymes. On the other hand, metabolites indicating the enzymatic transformation of both CHX and OCT were detected and their chemical structures were proposed by means of liquid chromatography–mass spectrometry. Complete biodegradation by the ligninolytic fungi was not achieved for any of the studied analytes, which emphasizes their recalcitrant character with low possibility to be removed from the environment. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessArticle
Heavy Metals as a Factor Increasing the Functional Genetic Potential of Bacterial Community for Polycyclic Aromatic Hydrocarbon Biodegradation
Molecules 2020, 25(2), 319; https://doi.org/10.3390/molecules25020319 - 13 Jan 2020
Abstract
The bioremediation of areas contaminated with hydrocarbon compounds and heavy metals is challenging due to the synergistic toxic effects of these contaminants. On the other hand, the phenomenon of the induction of microbial secretion of exopolysaccharides (EPS) under the influence of heavy metals [...] Read more.
The bioremediation of areas contaminated with hydrocarbon compounds and heavy metals is challenging due to the synergistic toxic effects of these contaminants. On the other hand, the phenomenon of the induction of microbial secretion of exopolysaccharides (EPS) under the influence of heavy metals may contribute to affect the interaction between hydrophobic hydrocarbons and microbial cells, thus increasing the bioavailability of hydrophobic organic pollutants. The purpose of this study was to analyze the impact of heavy metals on the changes in the metapopulation structure of an environmental consortium, with particular emphasis on the number of copies of orthologous genes involved in exopolysaccharide synthesis pathways and the biodegradation of hydrocarbons. The results of the experiment confirmed that the presence of heavy metals at concentrations of 50 mg·L−1 and 150 mg·L−1 resulted in a decrease in the metabolic activity of the microbial consortium and its biodiversity. Despite this, an increase in the biological degradation rate of polycyclic aromatic hydrocarbons was noted of 17.9% and 16.9%, respectively. An assessment of the estimated number of genes crucial for EPS synthesis and biodegradation of polycyclic aromatic hydrocarbons confirmed the relationship between the activation of EPS synthesis pathways and polyaromatic hydrocarbon biodegradation pathways. It was established that microorganisms that belong to the Burkholderiales order are characterized by a high representation of the analyzed orthologs and high application potential in areas contaminated with heavy metals and hydrocarbons. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessArticle
Δ-FeOOH as Support for Immobilization Peroxidase: Optimization via a Chemometric Approach
Molecules 2020, 25(2), 259; https://doi.org/10.3390/molecules25020259 - 08 Jan 2020
Abstract
Owing to their high surface area, stability, and functional groups on the surface, iron oxide hydroxide nanoparticles have attracted attention as enzymatic support. In this work, a chemometric approach was performed, aiming at the optimization of the horseradish peroxidase (HRP) immobilization process on [...] Read more.
Owing to their high surface area, stability, and functional groups on the surface, iron oxide hydroxide nanoparticles have attracted attention as enzymatic support. In this work, a chemometric approach was performed, aiming at the optimization of the horseradish peroxidase (HRP) immobilization process on Δ-FeOOH nanoparticles (NPs). The enzyme/NPs ratio (X1), pH (X2), temperature (X3), and time (X4) were the independent variables analyzed, and immobilized enzyme activity was the response variable (Y). The effects of the factors were studied using a factorial design at two levels (−1 and 1). The biocatalyst obtained was evaluated for the ferulic acid (FA) removal, a pollutant model. The materials were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The SEM images indicated changes in material morphology. The independent variables X1 (−0.57), X2 (0.71), and X4 (0.42) presented the significance effects estimate. The variable combinations resulted in two significance effects estimates, X1*X2 (−0.57) and X2*X4 (0.39). The immobilized HRP by optimized conditions (X1 = 1/63 (enzyme/NPs ratio, X2 = pH 8, X4 = 60 °C, and 30 min) showed high efficiency for FA oxidation (82%). Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessArticle
Analysis of Pollution of Phthalates in Pork and Chicken in Taiwan Using Liquid Chromatography–Tandem Mass Spectrometry and Assessment of Health Risk
Molecules 2019, 24(21), 3817; https://doi.org/10.3390/molecules24213817 - 23 Oct 2019
Abstract
Phthalates are widely used plasticizers that can cause endocrine disruption, mutagenicity, and carcinogenic effects and can contaminate food through various pathways. Investigations are scanty on phthalate pollution of livestock and poultry meat and their dietary exposure to humans. The present study assessed residual [...] Read more.
Phthalates are widely used plasticizers that can cause endocrine disruption, mutagenicity, and carcinogenic effects and can contaminate food through various pathways. Investigations are scanty on phthalate pollution of livestock and poultry meat and their dietary exposure to humans. The present study assessed residual levels of phthalates in unpackaged pork (30 samples) and unpackaged chicken (30 samples) and their relevance to meat consumption and health risks in the Taiwanese population. Phthalate quantity was assessed by liquid chromatography–tandem mass spectrometry; the materials included diisononyl phthalate, diisodecyl phthalate, benzyl butyl phthalate, di-2-ethylhexyl phthalate (DEHP), and di-n-butyl phthalate. The Taiwan Food and Drug Administration (TFDA) has established values of tolerable daily intake (TDI) for the five phthalates. The major compound detected was DEHP, which ranged from 0.62 to 0.80 mg/kg in two pork samples, and 0.42–0.45 mg/kg in three chicken samples. Collectively, 8.33% of the phthalate-residue-containing samples tested positive for DEHP. The concentrations of DEHP were lower than the screening value of 1.0 mg/kg, as defined by the TFDA. Health risk was calculated as the estimated daily intake (DI) for any likely adverse effects; the DI of DEHP residues was <1% of the TDI value. The estimated risk was insignificant and considered to be safe, indicating that there is no risk to the health of Taiwanese population due to meat consumption. However, it is suggested that a phthalate monitoring program in meat should be instituted for any possible effects in future on human health. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)

Review

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Open AccessFeature PaperReview
Microbial Degradation of Hydrocarbons—Basic Principles for Bioremediation: A Review
Molecules 2020, 25(4), 856; https://doi.org/10.3390/molecules25040856 (registering DOI) - 14 Feb 2020
Abstract
Crude oil-derived hydrocarbons constitute the largest group of environmental pollutants worldwide. The number of reports concerning their toxicity and emphasizing the ultimate need to remove them from marine and soil environments confirms the unceasing interest of scientists in this field. Among the various [...] Read more.
Crude oil-derived hydrocarbons constitute the largest group of environmental pollutants worldwide. The number of reports concerning their toxicity and emphasizing the ultimate need to remove them from marine and soil environments confirms the unceasing interest of scientists in this field. Among the various techniques used for clean-up actions, bioremediation seems to be the most acceptable and economically justified. Analysis of recent reports regarding unsuccessful bioremediation attempts indicates that there is a need to highlight the fundamental aspects of hydrocarbon microbiology in a clear and concise manner. Therefore, in this review, we would like to elucidate some crucial, but often overlooked, factors. First, the formation of crude oil and abundance of naturally occurring hydrocarbons is presented and compared with bacterial ability to not only survive but also to utilize such compounds as an attractive energy source. Then, the significance of nutrient limitation on biomass growth is underlined on the example of a specially designed experiment and discussed in context of bioremediation efficiency. Next, the formation of aerobic and anaerobic conditions, as well as the role of surfactants for maintaining appropriate C:N:P ratio during initial stages of biodegradation is explained. Finally, a summary of recent scientific reports focused on the removal of hydrocarbon contaminants using bioaugmentation, biostimulation and introduction of surfactants, as well as biosurfactants, is presented. This review was designed to be a comprehensive source of knowledge regarding the unique aspects of hydrocarbon microbiology that may be useful for planning future biodegradation experiments. In addition, it is a starting point for wider debate regarding the limitations and possible improvements of currently employed bioremediation strategies. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessReview
Current Approaches to and Future Perspectives on Methomyl Degradation in Contaminated Soil/Water Environments
Molecules 2020, 25(3), 738; https://doi.org/10.3390/molecules25030738 - 08 Feb 2020
Abstract
Methomyl is a broad-spectrum oxime carbamate commonly used to control arthropods, nematodes, flies, and crop pests. However, extensive use of this pesticide in agricultural practices has led to environmental toxicity and human health issues. Oxidation, incineration, adsorption, and microbial degradation methods have been [...] Read more.
Methomyl is a broad-spectrum oxime carbamate commonly used to control arthropods, nematodes, flies, and crop pests. However, extensive use of this pesticide in agricultural practices has led to environmental toxicity and human health issues. Oxidation, incineration, adsorption, and microbial degradation methods have been developed to remove insecticidal residues from soil/water environments. Compared with physicochemical methods, biodegradation is considered to be a cost-effective and ecofriendly approach to the removal of pesticide residues. Therefore, micro-organisms have become a key component of the degradation and detoxification of methomyl through catabolic pathways and genetic determinants. Several species of methomyl-degrading bacteria have been isolated and characterized, including Paracoccus, Pseudomonas, Aminobacter, Flavobacterium, Alcaligenes, Bacillus, Serratia, Novosphingobium, and Trametes. The degradation pathways of methomyl and the fate of several metabolites have been investigated. Further in-depth studies based on molecular biology and genetics are needed to elaborate their role in the evolution of novel catabolic pathways and the microbial degradation of methomyl. In this review, we highlight the mechanism of microbial degradation of methomyl along with metabolic pathways and genes/enzymes of different genera. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessReview
Digital PCR as an Emerging Tool for Monitoring of Microbial Biodegradation
Molecules 2020, 25(3), 706; https://doi.org/10.3390/molecules25030706 (registering DOI) - 06 Feb 2020
Abstract
Biodegradation of contaminants is extremely complicated due to unpredictable microbial behaviors. Monitoring of microbial biodegradation drives us to determine (1) the amounts of specific degrading microbes, (2) the abundance, and (3) expression level of relevant functional genes. To this endeavor, the cultivation independent [...] Read more.
Biodegradation of contaminants is extremely complicated due to unpredictable microbial behaviors. Monitoring of microbial biodegradation drives us to determine (1) the amounts of specific degrading microbes, (2) the abundance, and (3) expression level of relevant functional genes. To this endeavor, the cultivation independent polymerase chain reaction (PCR)-based monitoring technique develops from endpoint PCR, real-time quantitative PCR, and then into novel digital PCR. In this review, we introduce these three categories of PCR techniques and summarize the timely applications of digital PCR and its superiorities than qPCR for biodegradation monitoring. Digital PCR technique, emerging as the most accurately absolute quantification method, can serve as the most promising and robust tool for monitoring of microbial biodegradation. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessReview
Microbial Conversion of Toxic Resin Acids
Molecules 2019, 24(22), 4121; https://doi.org/10.3390/molecules24224121 - 14 Nov 2019
Abstract
Organic wood extractives—resin acids—significantly contribute to an increase in the toxicity level of pulp and paper industry effluents. Entering open ecosystems, resin acids accumulate and have toxic effects on living organisms, which can lead to the ecological imbalance. Among the most effective methods [...] Read more.
Organic wood extractives—resin acids—significantly contribute to an increase in the toxicity level of pulp and paper industry effluents. Entering open ecosystems, resin acids accumulate and have toxic effects on living organisms, which can lead to the ecological imbalance. Among the most effective methods applied to neutralize these ecotoxicants is enzymatic detoxification using microorganisms. A fundamental interest in the in-depth study of the oxidation mechanisms of resin acids and the search for their key biodegraders is increasing every year. Compounds from this group receive attention because of the need to develop highly effective procedures of resin acid removal from pulp and paper effluents and also the possibility to obtain their derivatives with pronounced pharmacological effects. Over the past fifteen years, this is the first report analyzing the data on distribution, the impacts on living organisms, and the microbial transformation of resin acids. Using the example of dehydroabietic acid—the dominant compound of resin acids in effluents—the review discusses the features of interactions between microorganisms and this pollutant and also highlights the pathways and main products of resin acid bioconversion. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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Open AccessReview
Petroleum Hydrocarbon Contamination in Terrestrial Ecosystems—Fate and Microbial Responses
Molecules 2019, 24(18), 3400; https://doi.org/10.3390/molecules24183400 - 19 Sep 2019
Cited by 2
Abstract
Petroleum hydrocarbons represent the most frequent environmental contaminant. The introduction of petroleum hydrocarbons into a pristine environment immediately changes the nature of that environment, resulting in reduced ecosystem functionality. Natural attenuation represents the single, most important biological process which removes petroleum hydrocarbons from [...] Read more.
Petroleum hydrocarbons represent the most frequent environmental contaminant. The introduction of petroleum hydrocarbons into a pristine environment immediately changes the nature of that environment, resulting in reduced ecosystem functionality. Natural attenuation represents the single, most important biological process which removes petroleum hydrocarbons from the environment. It is a process where microorganisms present at the site degrade the organic contaminants without the input of external bioremediation enhancers (i.e., electron donors, electron acceptors, other microorganisms or nutrients). So successful is this natural attenuation process that in environmental biotechnology, bioremediation has developed steadily over the past 50 years based on this natural biodegradation process. Bioremediation is recognized as the most environmentally friendly remediation approach for the removal of petroleum hydrocarbons from an environment as it does not require intensive chemical, mechanical, and costly interventions. However, it is under-utilized as a commercial remediation strategy due to incomplete hydrocarbon catabolism and lengthy remediation times when compared with rival technologies. This review aims to describe the fate of petroleum hydrocarbons in the environment and discuss their interactions with abiotic and biotic components of the environment under both aerobic and anaerobic conditions. Furthermore, the mechanisms for dealing with petroleum hydrocarbon contamination in the environment will be examined. When petroleum hydrocarbons contaminate land, they start to interact with its surrounding, including physical (dispersion), physiochemical (evaporation, dissolution, sorption), chemical (photo-oxidation, auto-oxidation), and biological (plant and microbial catabolism of hydrocarbons) interactions. As microorganism (including bacteria and fungi) play an important role in the degradation of petroleum hydrocarbons, investigations into the microbial communities within contaminated soils is essential for any bioremediation project. This review highlights the fate of petroleum hydrocarbons in tertial environments, as well as the contributions of different microbial consortia for optimum petroleum hydrocarbon bioremediation potential. The impact of high-throughput metagenomic sequencing in determining the underlying degradation mechanisms is also discussed. This knowledge will aid the development of more efficient, cost-effective commercial bioremediation technologies. Full article
(This article belongs to the Special Issue Biodegradation of Conventional and Emerging Pollutants)
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