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This article is a state–of-the-art review on the aerobic degradation of petroleum components that are commonly found in the environment. Numerous microorganisms have been isolated and their phylogeny and metabolic capacity to degrade a variety of aliphatic and aromatic hydrocarbons have been demonstrated. This review focuses on recent progress on h...
Citations
... Common remediation treatments for PAHs in soils include landfill transfer (Camenzuli & Gore, 2013), thermal desorption (Zhao et al., 2019), pyrolysis (Liu et al., 2022), incineration (Kuppusamy et al., 2017), vitrification (US-EPA, 2000), soil washing (Cazals et al., 2020), chemical oxidation (Ranc et al., 2016) and/or bioremediation (Olajire & Essien, 2014;Sakshi et al., 2021). Solidify and Stabilize technologies (S/S) are a key strategy employed to mitigate the mobility of pollutants in areas where pollutants pose a risk of spreading . ...
Soil stabilization/solidification is commonly employed remediation method for contaminated soils. Until now, limited attention has been given to the application of quicklime in polycyclic aromatic hydrocarbons (PAHs) contaminated soil. We treated a tectogenic industriosol spiked with 50 mg.kg-1 of four PAHs (12.5 mg.kg-1 each of fluorene (FLU), phenanthrene (PHE), fluoranthene (FLT) and pyrene (PYR)) using three different liming agents at 1% (w:w): quicklime (CaO), hydrated lime (Ca(OH)2) and carbonate calcium (CaCO3). All treated samples were leached in water at a solid-liquid ratio of 10, with subsequent analysis of leached soil and leachates for PAHs content. Results revealed that the addition of liming agents led to a reduction in FLU and PHE concentrations in treated soil by 6.81 ± 2.47% and 28.88 ± 4.18%, respectively, compared to a not-treated sol. However, no significant impact was observed on the 4-cycles PAHs (FLT and PYR). The addition of liming agents also significantly decreased the amount of PAHs in the leachate, by 100% for FLU and PHE, and by 74.9 ± 17.5% and 72.3 ± 34.8%, for FLT and PYR, respectively, compared to not limed soil. Among the liming agents, quicklime was the most effective in reducing the amount of 4 cycles PAHs in the leachate. Various mechanisms, such as encapsulation, volatilization and oxidation could contribute to this observed reduction. Quicklime treatment at a concentration of 1% w:w in PAHs-contaminated soil emerges as a promising technique to effectively reduce PAHs concentration in soils and mitigate PAHs mobility through leaching. This study also sheds light on the possibility to limit CO2 emissions and resources exploitation to assure the remediation process, thereby enhancing its overall environmental sustainability.
Keywords: leaching, lime, PAH, remediation, soil, stabilisation/solidification
... Microorganisms degrade the components of crude oil aerobically and anaerobically, gradually transforming them from long-chain complex compounds to small-molecule carboncontaining compounds. Aerobic degradation, involving both facultative anaerobic and aerobic microorganisms, breaks down petroleum hydrocarbons into small molecules like carbon dioxide through the action of oxygenase enzymes, utilizing molecular oxygen as the electron acceptor [75]. In contrast to aerobic degradation, anaerobic degradation is slower and continuous. ...
Crude oil gasification bacteria, including fermenting bacteria, hydrocarbon-oxidizing bacteria, reducing bacteria, and methanogenic bacteria, participate in multi-step reactions involving initial activation, intermediate metabolism, and the methanogenesis of crude oil hydrocarbons. These bacteria degrade crude oil into smaller molecules such as hydrogen, carbon dioxide, acetic acid, and formic acid. Ultimately, they convert it into methane, which can be utilized or stored as a strategic resource. However, the current challenges in crude oil gasification include long production cycles and low efficiency. This paper provides a summary of the microbial flora involved in crude oil gasification, the gasification metabolism pathways within reservoirs, and other relevant information. It specifically focuses on analyzing the factors that affect the efficiency of crude oil gasification metabolism and proposes suggestions for improving this efficiency. These studies deepen our understanding of the potential of reservoir ecosystems and provide valuable insights for future reservoir development and management.
... Microbial degradation of the crude oil fractions follows an ease of degradation from bioavailable to recalcitrant compounds, typically in the order of n-alkanes > branched alkanes > aromatics > cyclic alkanes > polycyclic aromatic hydrocarbons > resins and asphaltenes (Das and Chandran, 2011;Varjani, 2017;Varjani and Upasani, 2017). This results in a succession of microbial bloom and death as compounds are consumed (Hazen et al., 2010;Olajire and Essien, 2014;Mahjoubi et al., 2018). Hence, these microbes are working in conjunction with each other with their varying enzymatic capabilities to provide a dynamic community response to this contaminant. ...
... Alkane-degrading families, such as Alcanivorax and Flavobacterium, and PAH-degrading strains, such as Micrococcales and Oceanicola, could indicate the biodegradation of the different hydrocarbon fractions found in crude oil. In addition to the increased biodiversity, aerobic biodegradation has a lower energy input for a higher energy output when compared to anaerobic biodegradation of hydrocarbons (Olajire and Essien, 2014). These factors could play a role in the hydrocarbon degradation patterns measured by the GC-MS where the relative abundance of aliphatic and aromatic hydrocarbons were significantly reduced by day 115 (Figures 8, 9). ...
Introduction
The Caspian Sea is the world’s largest landlocked saline lake which lies between Europe and Asia. This region is particularly known for its large-scale oil reserves, pipelines, and drilling activities, which have contributed to the environmental decline of this lake. In addition to pollution from the petroleum industry, drainage from various river basins brings an influx of residential, industrial, and agricultural effluents that induce eutrophication and hypoxic conditions in deeper, colder waters, creating an oxygen gradient. The temperature and oxygen stratification in this environment has presented a unique opportunity to investigate the potential of the biodegradative processes carried out by the indigenous microbial community. We believe these indigenous microbes possess different metabolic capabilities to degrade oil as they adapted to declining oxygen concentrations and temperatures with increasing depths over a prolonged period. Hence, community structure and composition will vary with depth.
Methods
Microcosms were set up to observe the indigenous microbial reaction after a 60 ppm native crude oil amendment over 115 days. Surface water microcosms were incubated at 28ºC and aerated while deep water microcosms were incubated at 8ºC under anaerobic conditions. These two environmental conditions represent the temperature and oxygen extremes along the gradient and were selected as we try to simulate the indigenous community’s response to this oil contamination. DNA was extracted and amplified from these microcosms and sequenced. Bioinformatic analysis was performed to track changes in the abundance of taxa present and biodiversity over different time points to show the progression of community structure.
Results
All microcosms showed the presence of hydrocarbon-degrading phyla, whose presence is consistent with other reports from oil-enriched environments. However, distinct communities were observed in oxic versus hypoxic microcosms.
Conclusion
Orders of Bacteria related to sulfate and nitrogen cycling were found in hypoxic microcosms, indicating a possible mechanism for the anaerobic biodegradation of crude oil. GC-MS analysis of initial and final microcosms also provided evidence of degradation of hydrocarbon fractions in both warm, oxic and cold, hypoxic conditions.
... Some PAHs are highly toxic, mutagenic, carcinogenic, and represent a worldwide concern, due to their harmful potential to human populations, animals and the environment (Haritash & Kaushik, 2009;Hesham et al., 2009;Passarini et al., 2011;Stapleton et al., 1998;Ting et al., 2011). Currently, there are a variety of technologies available, and well established to recover environments impacted with PAHs, however, bioremediation has been chosen, as it is a clean, promising, effective and cost-effective technology (Felisardo & Gonçalves, 2023;Olajire & Essien, 2014;Schippers et al., 2000). ...
There is a demand for new microorganisms with the potential to degrade recalcitrant petroleum compounds, such as polycyclic aromatic hydrocarbons (PAHs). The objective of this research was to evaluate the potential of the AM15 strain isolated from water samples from the effluent dike of the Urucu petroleum Province, to degrade a mixture of PAHs. After isolation in culture medium, and initial screening by Gram stain, it was found to be yeast. The characterization of the strain was carried out by analysis based on the sequences of the polymorphic regions ITS1/ITS2 and D1/D2 of the 28S rRNA gene, concomitant with the restriction fragment size polymorphism, generated by the Polymerase Chain Reaction-Fragment Length Polymorphism of Restriction (PCR-RFLP). The ability of yeast to degrade petroleum compounds was determined by testing with the redox indicator 2,6-Dichlorophenol Indophenol (DCPIP), and degradation was confirmed and quantified by gas chromatography and mass spectrometry (GC-MS) analyses. Molecular analyzes indicated that the AM15 strain belongs to the Diutina mesorugosa species. The results obtained in the test carried out with DCPIP showed that the AM15 strain has the potential to degrade hydrocarbons present in petroleum and diesel oil. GC-MS analyzes confirmed that the AM15 strain was able to degrade 79.4% of a mixture of PAHs in 21 days. These results suggest that D. mesorugosa AM15 is promising to degrade different types of hydrocarbons, and can be used as a tool in the bioremediation of oil-impacted areas.
... The degradation pathways of aromatic hydrocarbons, however, indicate that they are initially oxidized to catechol (benzene-1, 2-diol) [15,67]. Thereafter, cleavage of the benzene ring occurs in either of two routes: the ortho-cleavage pathway, which involves cleavage between carbons 1 and 2 catalysed by catechol-1, 2-dioxygenase to produce ketones and esters, and the meta-cleavage pathway, which involves cleavage between carbons 2 and 3 by catechol-2, 3-dioxygenase to produce aldehydes and carboxylic acids [57,68]. From the elucidated pathways, and as observed during this study, ketones and aldehydes are key distinguishing metabolites in determining the catabolic pathways utilized by the bacterial community. ...
... From the elucidated pathways, and as observed during this study, ketones and aldehydes are key distinguishing metabolites in determining the catabolic pathways utilized by the bacterial community. Aldehydes are the distinguishing metabolites for the terminal oxidation pathway of aliphatics and meta-oxidation pathway of aromatics [58,68,69]. Ketones, on the other hand, distinguish the activity of the subterminal oxidation pathway of aliphatics and the ortho-oxidation pathway of aromatics [5,58]. ...
Brewery spent grain (BSG) has previously been exploited in bioremediation. However, detailed knowledge of the associated bacterial community dynamics and changes in relevant metabolites and genes over time is limited. This study investigated the bioremediation of diesel contaminated soil amended with BSG. We observed complete degradation of three total petroleum hydrocarbon (TPH C10-C28) fractions in amended treatments as compared to one fraction in the unamended, natural attenuation treatments. The biodegradation rate constant (k) was higher in amended treatments (0.1021k) than in unamended (0.059k), and bacterial colony forming units increased significantly in amended treatments. The degradation compounds observed fitted into the elucidated diesel degradation pathways and quantitative PCR results showed that the gene copy numbers of all three associated degradation genes, alkB, catA and xylE, were significantly higher in amended treatments. High-throughput sequencing of 16S rRNA gene amplicons showed that amendment with BSG enriched autochthonous hydrocarbon degraders. Also, community shifts of the genera Acinetobacter and Pseudomonas correlated with the abundance of catabolic genes and degradation compounds observed. This study showed that these two genera are present in BSG and thus may be associated with the enhanced biodegradation observed in amended treatments. The results suggest that the combined evaluation of TPH, microbiological, metabolite and genetic analysis provides a useful holistic approach to assessing bioremediation.
... Suitably, relevant studies (e.g., Brooijmans et al. [13], 14] have widely reported the existence and proliferation of some crucial microorganisms capable of utilizing or degrading petroleum hydrocarbon contaminants in the environment. Even though, many bioremediation studies have demonstrated successful methods (e.g., physical, chemical and biological approaches [15,16]) for reclaiming petroleum hydrocarboncontaminated land. ...
Petroleum hydrocarbon-polluted environments contain massive diversity of microbes capable of transforming or reducing hydrocarbon concentrations, and this has consequently led to an interest in the cultivation screening for microbial potentials to remediate petroleum hydrocarbon-polluted lands. Conversely, the reliance singly on culturing approach for the discovery of various hydrocarbon-degrading bacteria without probing for its hydrocarbon degradative capabilities has now become rampant in some research communities, and in most cases may not be justifiable. Besides, vast microbial communities with hydrocarbon-degrading potentials are eluded with the conventional method. Opportunely, the advent of culture-independent approaches such as molecular techniques and next-generation sequencing (NGS) technology has shifted the paradigm of research, now focusing on contemporary and advanced trending ways to discover the uncultivable microbial communities and assess their functional roles in the environment. To ascertain that microorganisms cultured from polluted environmental samples are factual hydrocarbon-degrading strains, a microbiologist needs to investigate beyond just culturing and probe further for the hydrocarbon-degrading prowess by choosing from various arrays of the culture-independent approaches. Consequently, this counters the questionability of only the cultivation approach and explores the vast recompenses of the latter approach when coupled. This perspective review exposes the huge gap in the application of the lone conventional culturing technique for retrieving the uncultured communities, particularly the hydrocarbon-degrading group while hinting at complementary alternatives for improved research and scientific evidence-driven and justifiable study inference.
... It should be noted that the microbial respiration of the soil with a minimum dose of oil was lower than that of more contaminated soils during all observation periods, although it exceeded the respiration level of the control (clean) soil. Possibly, the higher degradation activity of microorganisms in heavily contaminated samples is explained by the fact that soils with a high oil content contain significantly more oiloxidizing microbiota than in slightly contaminated variants (Olajire and Essien 2014). ...
Purpose
The aim of the research was to study the direction, dynamics, and features of the restoration of the main ecological functions of different podzolic soils disturbed by oil pollution.
Materials and methods
Soil contamination with crude oil was carried out in field experiments at two sites near St. Petersburg, Russia. Loamy soddy-podzolic soil (Umbric Albeluvisol) and sandy illuvial-ferruginous podzol (Podzol), the most common in the region, were the objects of study. Key indicators were used to investigate the dynamics of self-purification processes of oil-contaminated soils: (1) the rate of carbon dioxide emission by the soil, which quantitatively characterizes the mineralization of petroleum hydrocarbons by microorganisms, was determined by the absorption method in laboratory conditions; (2) toxicological rate of soils and water extracts from them was determined by eluate and substrate bioassay; (3) the value of aboveground biomass and the projective vegetation cover were determined by direct weighing out and visually. Content of petroleum products in soils was determined by infrared spectrometry.
Results and discussion
Self-purification and self-recovery dynamics in the oil-contaminated soils differed significantly depending on the soil type. The rate and intensity of oil biodegradation in the sandy podzol due to the activity of microorganisms, as well as the rate and degree of restoration of vegetation cover, were significantly lower compared to the soddy-podzolic soil, despite the same level of oil pollution. Podzol was characterized both by a higher degree of toxicity and a lower rate of its decline compared to the soddy-podzolic soil. The soddy-podzolic soil at the maximum level of pollution restored the disturbed basic ecological functions in 4 years. In podzol, with a comparable high pollution level, by the end of the fifth year, acute toxicity remained and there was practically no vegetation.
Conclusions
The factors affecting the rate of oil degradation should be associated primarily with the chemical and microbiological parameters of soils and the characteristics of the vegetation growing on them. Different levels of stability of the loamy soddy-podzolic soil and sandy podzol in conditions of oil pollution, and the peculiarities of the processes of their natural recovery, should be taken into account in environmental regulations, when determining the maximum permissible residual oil concentrations in soils, as well as in the development of effective methods for their reclamation.
... According to McNally et al. [98] and Grishchenkov et al. [99], the biodegradation of PAHs was slower in anaerobic conditions compared to aerobic conditions. Under aerobic conditions, the bulk of organic pollutants degrade at the fastest and most complete rate [100]. This has been demonstrated in research by Mille et al. [101] (Table 1), for example, who found that when the dissolved oxygen concentration in the overlying seawater was 8 ppm and the redox potential was around +150 mV, hydrocarbon degradation was noticeable. ...
Over the past century, the demand for petroleum products has increased rapidly, leading to higher oil extraction, processing and transportation, which result in numerous oil spills in coastal-marine environments. As the spilled oil can negatively affect the coastal-marine ecosystems, its transport and fates captured a significant interest of the scientific community and regulatory agencies. Typically, the environment has natural mechanisms (e.g., photooxidation, biodegradation, evaporation) to weather/degrade and remove the spilled oil from the environment. Among various oil weathering mechanisms, biodegradation by naturally occurring bacterial populations removes a majority of spilled oil, thus the focus on bioremediation has increased significantly. Helping in the marginal recognition of this promising technique for oil-spill degradation, this paper reviews recently published articles that will help broaden the understanding of the factors affecting biodegradation of spilled oil in coastal-marine environments. The goal of this review is to examine the effects of various environmental variables that contribute to oil degradation in the coastal-marine environments, as well as the factors that influence these processes. Physico-chemical parameters such as temperature, oxygen level, pressure, shoreline energy, salinity, and pH are taken into account. In general, increase in temperature, exposure to sunlight (photooxidation), dissolved oxygen (DO), nutrients (nitrogen, phosphorous and potassium), shoreline energy (physical advection—waves) and diverse hydrocarbon-degrading microorganisms consortium were found to increase spilled oil degradation in marine environments. In contrast, higher initial oil concentration and seawater pressure can lower oil degradation rates. There is limited information on the influences of seawater pH and salinity on oil degradation, thus warranting additional research. This comprehensive review can be used as a guide for bioremediation modeling and mitigating future oil spill pollution in the marine environment by utilizing the bacteria adapted to certain conditions
... According to McNally et al. [98] and Grishchenkov et al. [99], the biodegradation of PAHs was slower in anaerobic conditions compared to aerobic conditions. Under aerobic conditions, the bulk of organic pollutants degrade at the fastest and most complete rate [100]. This has been demonstrated in research by Mille et al. [101] (Table 1), for example, who found that when the dissolved oxygen concentration in the overlying seawater was 8 ppm and the redox potential was around +150 mV, hydrocarbon degradation was noticeable. ...
Over the past century, the demand for petroleum products has increased rapidly, leading to higher oil extraction, processing and transportation, which result in numerous oil spills in coastal-marine environments. As the spilled oil can negatively affect the coastal-marine ecosystems, its transport and fates captured a significant interest of the scientific community and regulatory agencies. Typically, the environment has natural mechanisms (e.g., photooxidation, biodegradation, evaporation) to weather/degrade and remove the spilled oil from the environment. Among various oil weathering mechanisms, biodegradation by naturally occurring bacterial populations removes a majority of spilled oil, thus the focus on bioremediation has increased significantly. Helping in the marginal recognition of this promising technique for oil-spill degradation, this paper reviews recently published articles that will help broaden the understanding of the factors affecting biodegradation of spilled oil in coastal-marine environments. The goal of this review is to examine the effects of various environmental variables that contribute to oil degradation in the coastal-marine environments, as well as the factors that influence these processes. Physico-chemical parameters such as temperature, oxygen level, pressure, shoreline energy, salinity, and pH are taken into account. In general, increase in temperature, exposure to sunlight (photooxidation), dissolved oxygen (DO), nutrients (nitrogen, phosphorous and potassium), shoreline energy (physical advection—waves) and diverse hydrocarbon-degrading microorganisms consortium were found to increase spilled oil degradation in marine environments. In contrast, higher initial oil concentration and seawater pressure can lower oil degradation rates. There is limited information on the influences of seawater pH and salinity on oil degradation, thus warranting additional research. This comprehensive review can be used as a guide for bioremediation modeling and mitigating future oil spill pollution in the marine environment by utilizing the bacteria adapted to certain conditions.
... According to McNally et al. [98] and Grishchenkov et al. [99], the biodegradation of PAHs was slower in anaerobic conditions compared to aerobic conditions. Under aerobic conditions, the bulk of organic pollutants degrade at the fastest and most complete rate [100]. This has been demonstrated in research by Mille et al. [101] (Table 1), for example, who found that when the dissolved oxygen concentration in the overlying seawater was 8 ppm and the redox potential was around +150 mV, hydrocarbon degradation was noticeable. ...
Over the past century, the demand for petroleum products has increased rapidly, leading
to higher oil extraction, processing and transportation, which result in numerous oil spills in coastal-marine environments. As the spilled oil can negatively affect the coastal-marine ecosystems, its transport and fates captured a significant interest of the scientific community and regulatory agencies. Typically, the environment has natural mechanisms (e.g., photooxidation, biodegradation, evaporation) to weather/degrade and remove the spilled oil from the environment. Among various oil weathering mechanisms, biodegradation by naturally occurring bacterial populations removes a majority of spilled oil, thus the focus on bioremediation has increased significantly. Helping in the marginal recognition of this promising technique for oil-spill degradation, this paper reviews recently published articles that will help broaden the understanding of the factors affecting biodegradation of spilled oil in coastal-marine environments. The goal of this review is to examine the effects of various environmental variables that contribute to oil degradation in the coastal-marine environments, as well as the factors that influence these processes. Physico-chemical parameters such as temperature, oxygen level, pressure, shoreline energy, salinity, and pH are taken into account. In general, increase in temperature, exposure to sunlight (photooxidation), dissolved oxygen (DO), nutrients
(nitrogen, phosphorous and potassium), shoreline energy (physical advection—waves) and diverse hydrocarbon-degrading microorganisms consortium were found to increase spilled oil degradation in marine environments. In contrast, higher initial oil concentration and seawater pressure can lower oil degradation rates. There is limited information on the influences of seawater pH and salinity on oil degradation, thus warranting additional research. This comprehensive review can be used as a guide for bioremediation modeling and mitigating future oil spill pollution in the marine environment by utilizing the bacteria adapted to certain conditions.
