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A lot of oil is leaked into aquatic environments, significantly impacting fish health and, consequently, human populations. This study aimed to introduce an L-phenylalanine-based low-molecular-weight gelator (expressed as Z-Phe-C18) as a smart remediation tool for oil spills. Several groups of Nile tilapia were allocated in aquaria exposed to different doses of crude engine oil with/without the organogelator for 4 weeks. The results revealed a significant increase in biochemical oxygen demand, chemical oxygen demand, electrical conductivity, and total dissolved solids in water samples of fish aquaria exposed to oil pollution. The antioxidant activity levels, micronucleus formation, and expression patterns of stress-related genes were significantly higher in the livers of fish exposed to crude oil than in those of control fish. On the contrary, fish groups exposed to oil pollution and treated with the organogelator indicated that antioxidant enzymes, micronucleus incidence, and gene expression alteration of stress-related genes declined compared with those exposed to oil pollution only. The results suggest that oil pollution can induce oxidative stress via the enhancement of oxygen free radical formation. On the contrary, oil removal by the organogelator decreases oxidative stress and consequently strengthens fish immunity. So, we can conclude that organogelator treatment is promoting oxidative resistance development by increasing the activities of antioxidant enzymes, which are important in protection against oil pollution and preventing peroxidation of fish tissues. Promisingly, the organogelator could be used as a tool for the remediation of oil pollution in aquatic environments. [ABSTRACT FROM AUTHOR]

A lot of oil is leaked into aquatic environments, significantly impacting fish health and, consequently, human populations. This study aimed to introduce an L-phenylalanine-based low-molecular-weight gelator (expressed as Z-Phe-C18) as a smart remediation tool for oil spills. Several groups of Nile tilapia were allocated in aquaria exposed to different doses of crude engine oil with/without the organogelator for 4 weeks. The results revealed a significant increase in biochemical oxygen demand, chemical oxygen demand, electrical conductivity, and total dissolved solids in water samples of fish aquaria exposed to oil pollution. The antioxidant activity levels, micronucleus formation, and expression patterns of stress-related genes were significantly higher in the livers of fish exposed to crude oil than in those of control fish. On the contrary, fish groups exposed to oil pollution and treated with the organogelator indicated that antioxidant enzymes, micronucleus incidence, and gene expression alteration of stress-related genes declined compared with those exposed to oil pollution only. The results suggest that oil pollution can induce oxidative stress via the enhancement of oxygen free radical formation. On the contrary, oil removal by the organogelator decreases oxidative stress and consequently strengthens fish immunity. So, we can conclude that organogelator treatment is promoting oxidative resistance development by increasing the activities of antioxidant enzymes, which are important in protection against oil pollution and preventing peroxidation of fish tissues. Promisingly, the organogelator could be used as a tool for the remediation of oil pollution in aquatic environments.

Biosurfactants are a diverse group of amphiphilic compounds obtained from microbes. In the present study, the genomic analysis of biosurfactant-producing Bacillus subtilis MB415 and MB418 obtained from oil-contaminated soil was performed. Initially, the strains were screened for biosurfactant production by hemolytic assay, emulsification index, and oil displacement. Further FTIR analysis of extracted biosurfactants revealed the presence of lipopeptides. The sequenced genomes of MB415 and MB418 were of 4.2 Mbps with 43% GC content. Among more than 4,500 protein-coding genes, many were involved in virulence, metal/multidrug resistances, flagella assembly, chemotactic response, and aromatic ring hydroxylating dioxygenases. An annotation analysis revealed that both genomes possessed non-ribosomal synthetase gene clusters for the lipopeptide synthetases srf and fen responsible for surfactin and fengycin production. Comparative studies of both genomes highlighted variability in gene operons mainly for surfactin biosynthesis.

Biosurfactants are naturally occurring compounds synthesized by micro-organisms that increasingly attract attention due to both their living area and application in various industries. In this study, we explore and characterize a novel bacterium, Enterobacter quasihormaechei strain BDIFST24001, isolated for its ability to produce rhamnolipid biosurfactants, with the aim of facilitating oil remediation processes. The isolation of this bacterium was carried out using Luria-Bertani (LB) broth media from environmental samples collected from oil-contaminated sites in Dhaka City. Screening tests, including the oil spreading method and drop collapse assay, were conducted to identify potential biosurfactant-producing strains, leading to the selection of E. quasihormaechei strain BDIFST24001 based on its favourable performance. Subsequent molecular identification revealed a high similarity of the strain's 16S rRNA gene to E. quasihormaechei , which was corroborated through phylogenetic analysis. Further analysis of the biosurfactant produced by this strain indicated its rhamnolipid nature, as confirmed by FT-IR spectroscopy. The rhamnolipids exhibited promising surface-active properties, including a significant reduction in surface tension and emulsification activity, as evidenced by surface tension measurements and emulsification index assays. Optimization studies revealed that the optimal conditions for rhamnolipid production by E. quasihormaechei strain BDIFST24001 were a temperature of 37 °C, pH 10.0 and salinity of 4 %. The rhamnolipids produced by this strain demonstrated effective oil remediation capabilities, as observed through controlled experiments using petrol oil. The rhamnolipids effectively reduced the surface tension of the oil-water interface, facilitating the dispersion and emulsification of the oil phase in water. Overall, our findings highlight the potential of E. quasihormaechei strain BDIFST24001 as a promising candidate for biosurfactant-mediated oil spill cleanup and environmental remediation efforts., Competing Interests: The authors stated that they have no identifiable financial conflicts of interest or personal relationships that could potentially bias the results reported in this paper., (Copyright © 2024 The Authors.)

The inefficient cleanup of viscous heavy oil is thought as a worldwide problem because of its poorer fluidity at room temperature. Herein, we make full use of the photothermal performance to harvest solar energy and convert heat into heavy oil, thus reducing significantly oil viscosity and realizing rapid oil remediation. Specially, the polydopamine as photothermal components, titanium dioxide and perfluorodecyltrichlorosilane as superhydrophobic/superoleophilic source are introduced into the melamine-formaldehyde sponge by deposition method. To be applicable in the marine environments with winds and waves, the bottom side of this sponge subjected to UV irradiation is transferrable from superhydrophobicity to superhydrophilicity. The Janus sponge can keep the balance of movement and never overturned under the action of wind force, thereby enabling this sponge to absorb consecutively spilled heavy oil from marine system. With one simulated solar irradiation, the top and bottom of Janus sponge are heated to a suitable temperature of 90.7 and 70.2 °C, respectively. Relied on these advantages, the Janus sponge can effectively reduce the viscosity of spilled heavy oil and enhance its fluidity, which allow for quick heavy oil absorption up to nearly 12 times of own weight. Meanwhile, it can be also compressed for recycled uses.

Releases of crude oil and other types of oil from numerous sources can impose catastrophic physical, chemical, and biological effects on aquatic ecosystems. While currently-used oil removal techniques possess many advantages, they have inherent limitations, including low removal efficiencies and waste disposal challenges. The present study quantified the synergistic interactions of polyvinylpyrrolidone (PVP) coated magnetite nanoparticles (NP) and oil-degrading bacteria for enhanced oil removal at the laboratory scale. The results showed that at relatively high oil concentrations (375 mg L −1 ), NP alone could remove approximately 70% of lower-chain alkanes (C9–C22) and 65% of higher-chain (C23–C26), after only 1 h, when magnetic separation of NP was used. Removal efficiency did not increase significantly after that, which was likely due to saturation of the NP with oil. Microbial bioremediation, using strains of oil-degrading bacteria, removed almost zero oil immediately but 80–90% removal after 24–48 h. The combination of NPs and oil-degrading bacterial strains worked effectively to remove essentially 100% of oil within 48 h or less. This was likely due to the sorption of oil components to NPs and their subsequent utilization by bacteria as a joint Fe and C source, although the mechanisms of removal require further testing. Furthermore, results showed that the emission of selected volatile organic compounds (VOCs) and semi volatile organic compounds (SVOCs) were reduced after addition of NPs and bacteria separately. When combined, VOC and SVOC emissions were reduced by up to 80%. [ABSTRACT FROM AUTHOR]

Development of durable and eco-friendly adsorbents for oil remediation is in great demands. However, most of adsorbents were designed to pursue large capabilities while ignored their strength after adsorbing oil, which might cause secondary oil spilling during complex salvage process. Herein, an eco-friendly and superhydrophobic SiO 2 -modified polyvinyl alcohol composite (H–SiO 2 -G-PVA) sponge with extraordinary rigid structure after oil adsorption is designed for durable oil remediation. Through a two-step hydrolysis-condensation process including deposition of silica microparticles and introduction of hexadecyltrimethoxysilane (HDTMS), a superhydrophobic H–SiO 2 -G-PVA sponge has been successfully constructed. The sponge presents stable superhydrophobicity in various complex environments，therefore it efficiently adsorbs oil from water (up to 6 g g−1) and separate surfactant-stabilized water/oil emulsion with high efficiency (>99%). Noticeably, the H–SiO 2 -G-PVA sponge maintains tough strength (3.5 MPa) after oil adsorption, which ideally overcomes secondary oil spilling problem and endows the sponge with excellent recycling performances (>20 cycles). Meanwhile, the excellent biocompatibility of the sponge (high cell viability of 91.85%) ensures the potential for practical applications. This rigid, eco-friendly oil-adsorbing sponge that achieves stable superhydrophobicity and recyclability, fulfills the application needs for durable oil remediation. [Display omitted] • An eco-friendly H–SiO 2 -G-PVA sponge is prepared by hydrolysis-condensation. • The composite sponge maintains rigid structure even after oil adsorption. • The sponge presents stable superhydrophobicity and recycling performances. • The sponge has high oil adsorption capacity and emulsion separation efficiency. • The sponge shows great potential for durable oil remediation. [ABSTRACT FROM AUTHOR]

Hydrocarbons are ubiquitous in the ocean, where alkanes such as pentadecane and heptadecane can be found even in waters minimally polluted with crude oil. Populations of hydrocarbon-degrading bacteria, which are responsible for the turnover of these compounds, are also found throughout marine systems, including in unpolluted waters. These observations suggest the existence of an unknown and widespread source of hydrocarbons in the oceans. Here, we report that strains of the two most abundant marine cyanobacteria, Prochlorococcus and Synechococcus, produce and accumulate hydrocarbons, predominantly C15 and C17 alkanes, between 0.022 and 0.368% of dry cell weight. Based on global population sizes and turnover rates, we estimate that these species have the capacity to produce 2-540 pg alkanes per mL per day, which translates into a global ocean yield of ~308-771 million tons of hydrocarbons annually. We also demonstrate that both obligate and facultative marine hydrocarbon-degrading bacteria can consume cyanobacterial alkanes, which likely prevents these hydrocarbons from accumulating in the environment. Our findings implicate cyanobacteria and hydrocarbon degraders as key players in a notable internal hydrocarbon cycle within the upper ocean, where alkanes are continually produced and subsequently consumed within days. Furthermore we show that cyanobacterial alkane production is likely sufficient to sustain populations of hydrocarbon-degrading bacteria, whose abundances can rapidly expand upon localized release of crude oil from natural seepage and human activities. [ABSTRACT FROM AUTHOR]

The application of bioremediation to marine oil spills is limited due to dilution of either nutrients or hydrocarbonoclastic organisms. This study investigated the effectiveness of three unique natural carrier materials (mussel shells, coir peat and mussel shell/agar complex) which allowed nutrients, hydrocarbonoclastic organisms and oil to be in contact, facilitating remediation. TPH analysis after 30 d showed that mussel shells exhibited the greatest capacity to degrade oil with a 55% reduction (123.3 mg l −1 from 276 mg l −1 ) followed by mussel shell/agar complex (49%) and coir peat (36%). Both the mussel shells and mussel shell/agar complex carriers were significantly different to the control ( P = 0.008 and P = 0.002, respectively). DGGE based cluster analysis of the seawater microbial community showed groupings based on time rather than carriers. This study demonstrated that inexpensive, accessible waste materials used as carriers of hydrocarbonoclastic bacteria led to significant degradation of hydrocarbon contaminants in seawater. [ABSTRACT FROM AUTHOR]

When a dispersant is applied to an oil slick, its effectiveness in dispersing the spilled oil depends on factors such as oil properties, wave-mixing energy, temperature, and salinity of the water. Estuaries represent water with varying salinity, so in this study, three salinity values in the range 10–34psu were investigated, representing potential salinity concentrations found in typical estuaries. Three oils were chosen to represent light refined oil, light crude oil, and medium crude oil. Each was tested at three weathering levels to represent maximum, medium, and zero weathering. Two dispersants were chosen for evaluation. A modified trypsinizing flask termed a baffled flask was used to conduct the experimental runs. A full factorial experiment was conducted for each oil. The interactions between the effects of salinity and three environmental factors, temperature, oil weathering, and mixing energy, on dispersion effectiveness were investigated. Each experiment was replicated four times in order to evaluate the accuracy of the test. Statistical analyses of the experimental data were performed for each of the three oils independently for each dispersant treatment (two dispersants and oil controls). A linear regression model representing the main factors (salinity, temperature, oil weathering, flask speed) and second-order interactions among the factors was fitted to the experimental data. Salinity played an important role in determining the significance of temperature and mixing energy on dispersant effectiveness for almost all the oil–dispersant combinations. The impact of salinity at different weathering was only significant for light crude oil with dispersant A. [Copyright &y& Elsevier]

The complexity of chemical and physical interactions between spilled oils, dispersants, and the sea necessitates an empirical approach for describing the interaction between the dispersant and oil slick, which may provide a guide to dispersant effects on oil slicks. Recently, U.S. EPA developed an improved laboratory dispersant testing protocol, called the baffled flask test (BFT). Use of this protocol was the basis for the experiments conducted in this study. A factorial experimental design was conducted in order to determine which of the factors temperature, oil type, oil weathering, dispersant type, and rotation speed of the shaker are related to the effectiveness of a dispersant used in oil remediation. Three oils were chosen to represent light refined oil [Number 2 Fuel Oil (2FO)], light crude oil [South Louisiana Crude Oil (SLC)] and medium crude oil [Prudhoe Bay Crude Oil (PBC)]. Statistical analyses of the experimental data performed separately for the three oils revealed that certain two-way interactions exist among the factors. For SLC, temperature and mixing energy were significant factors, for PBC, temperature, mixing energy, and weathering were significant and for 2FO, only temperature was a significant factor. Empirical relationships between the amount of oil dispersed and the variables studied were developed. [ABSTRACT FROM AUTHOR]

Field studies were conducted to evaluate Sagittaria lancifolia sensitivity to in-situ burning of applied crude oil. Twenty-four plots were constructed (2.4 × 2.4 × 0.6 m) in a fresh marsh and experimental treatments were: 1) control (no oiling and/or burning); 2) oiling (natural remediation); and 3) oiling plus burning. South Louisiana Crude was applied at 2 L m-2, with a garden sprayer, on Sagittaria lancifolia stems and leaves of the oiling and oiling/burning treatment plots. Two marsh burns were conducted, one in August (Site A) and a second on separate plots the following April (Site B) to compare seasonal effects of oiling and burning. Burning was initiated three days after oil application when the marsh was flooded to a 15–25 cm depth and winds were calm. Live stem count, plant height growth and carbon fixation were measured up to 9 times over 52 weeks after the first burn (August) and 6 times over 19 weeks after the second in-situ burn (April). Aboveground biomass was measured at the conclusion of each study. Oil application and oil burning had short term effects on Sagittaria lancifolia vegetation. Five to six weeks after each burn, measured Sagittaria lancifolia vegetative parameters in control, oiled and oiled/burned plots were not significantly different. Only biomass clipped 20 weeks after the April burn showed significant treatment differences. Under our experimental conditions, data suggests leaving oil to degrade and the marsh to recover naturally may be an option to consider. Plant recovery in oiled/burned plots was as rapid as oiled plant recovery. This suggests burning may be a viable remediation method if a rapid response is needed to remove oil and control oil migration to sensitive areas. [ABSTRACT FROM AUTHOR]

Biosurfactants are a diverse group of amphiphilic compounds obtained from microbes. In the present study, the genomic analysis of biosurfactant-producing Bacillus subtilis MB415 and MB418 obtained from oil-contaminated soil was performed. Initially, the strains were screened for biosurfactant production by hemolytic assay, emulsification index, and oil displacement. Further FTIR analysis of extracted biosurfactants revealed the presence of lipopeptides. The sequenced genomes of MB415 and MB418 were of 4.2 Mbps with 43% GC content. Among more than 4,500 protein-coding genes, many were involved in virulence, metal/multidrug resistances, flagella assembly, chemotactic response, and aromatic ring hydroxylating dioxygenases. An annotation analysis revealed that both genomes possessed non-ribosomal synthetase gene clusters for the lipopeptide synthetases srf and fen responsible for surfactin and fengycin production. Comparative studies of both genomes highlighted variability in gene operons mainly for surfactin biosynthesis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yasmin, Aslam and Fariq.)

Oil spill from petrochemical industries into marine areas has resulted in severe environmental pollution. The use of natural sorbents to clean marine areas affected by petroleum contaminants is a promising approach to alleviate this problem. Therefore, this study aims at developing an technique that uses waste coconut fibres (Cocos nucifera L.) pre-treated with a "green" solvent, viz. protic ionic liquid (PIL) [2-HEA][Ac], for the remediation of oil in saline water. Conventional chemical pre-treatments (mercerisation/acetylation) and the innovative treatment (using PIL), chemical characterisation, Scanning Electron Microscope, Fourier-transform infrared spectroscopy, and oil sorption tests in hydrodynamic simulation on a laboratory scale were conducted. The fibres treated with PIL[2-HEA][Ac] possessed more pores and hydrophobic content than the mercerised/acetylated coconut fibres, indicating the efficiency of sorption. The average sorption of the PIL[2-HEA][Ac] fibre was 1.40 ± 0.06 g/g and that of the mercerised/acetylated fibre was 1.32 ± 0.12 g/g. Although the difference in sorption results is not significant, according to the Tukey test, fibre pre-treatment with PIL[2-HEA][Ac] is more advantageous than conventional treatments because it exhibits better average sorption results; furthermore, the synthesis procedure for PIL[2-HEA][Ac] is simple, reusable and non-toxic. Therefore, the use of these petroleum biosorbents is a technology with environmental benefits, such as the availability of the biosorbent in the form of biodegradable waste and treated with a "green" solvent, both of which can be reused. Thus, it adds value for its use in industries with a circular economy product; that are environment-friendly and economical. [Display omitted] • Average sorption of Protic Ionic Liquid [2-HEA][Ac] treated fibre was 1.40 ± 0.06. • The average sorption of the mercerised/acetylated fibre was 1.32 ± 0.12 g/g. • Protic Ionic Liquid [2-HEA][Ac] treated fibres showed more pores and hydrophobia. • Protic Ionic Liquid treated fibres are products of Circular Economy. • Protic Ionic Liquid treated biosorbents are environment-friendly. [ABSTRACT FROM AUTHOR]

The inefficient cleanup of viscous heavy oil is thought as a worldwide problem because of its poorer fluidity at room temperature. Herein, we make full use of the photothermal performance to harvest solar energy and convert heat into heavy oil, thus reducing significantly oil viscosity and realizing rapid oil remediation. Specially, the polydopamine as photothermal components, titanium dioxide and perfluorodecyltrichlorosilane as superhydrophobic/superoleophilic source are introduced into the melamine-formaldehyde sponge by deposition method. To be applicable in the marine environments with winds and waves, the bottom side of this sponge subjected to UV irradiation is transferrable from superhydrophobicity to superhydrophilicity. The Janus sponge can keep the balance of movement and never overturned under the action of wind force, thereby enabling this sponge to absorb consecutively spilled heavy oil from marine system. With one simulated solar irradiation, the top and bottom of Janus sponge are heated to a suitable temperature of 90.7 and 70.2 °C, respectively. Relied on these advantages, the Janus sponge can effectively reduce the viscosity of spilled heavy oil and enhance its fluidity, which allow for quick heavy oil absorption up to nearly 12 times of own weight. Meanwhile, it can be also compressed for recycled uses. Unlabelled Image • The Janus sponge was successfully synthesized by successive deposition and final UV irradiation. • The Janus sponge exhibited five superhydrophobic sides and a superhydrophilic bottom side. • This Janus sponge exhibited excellent mechanical property at a strain of 80% and 50 cyclic compression tests. • The Janus sponge could keep excellent floating stability for 20 s or more under marine conditions with winds and waves. • The Janus sponge could absorb stably viscous heavy oil by photothermal effect, with absorption capacity to 11.2 g/g. [ABSTRACT FROM AUTHOR]

Remediation of wetland soils contaminated with petroleum hydrocarbons is a challenging task. Biosurfactant and biochar have been used in oil remediation. However, little is known about the ecotoxicity of these materials when applied in wetland ecosystems. In this study, the ecotoxicity of biochar and rhamnolipid (RL) biosurfactant as crude oil remediation strategies in a Louisiana wetland soil was investigated. A pot experiment was set up with wetland soil treated with/without crude oil followed by subjecting to application of 1% biochar and various levels of RL ranging from 0.1% to 1.4%. The ecotoxicity was evaluated regarding to high plant (S. Alterniflora), algae, and soil microbes. Specifically, after a 30-day growth in a controlled chamber, plant biomass change as well as shoot/root ratio was measured. Algae growth was estimated by quantifying chlorophyll by spectrometry following separation, and soil microbial community was characterized by phospholipid fatty acids analysis. Results showed that plant can tolerate RL level up to 0.8%, while algae growth was strongly inhibited at RL > 0.1%. Algal biomass was significantly increased by biochar, which offset the negative impact of oil and RL. Additionally, soil microbial community shift caused by crude oil and RL was alleviated by biochar with promoting Gram-positive bacteria, actinomycetes, and arbuscular mycorrhizal fungi. Overall, this study shows that integrated treatment of biochar and RL has the lowest ecotoxicity to plant and algae when used in oil remediation of contaminated wetland soils. Image 1 • Rhamnolipid biosurfactant reduced the phytotoxicity induced by oil. • Rhamnolipids has strong inhibition on algae growth. • Biochar decreased nutrient stress on soil microbes induced by oil and rhamnolipids. • Rhamnolipids together with biochar show lower ecotoxicity for wetland application. [ABSTRACT FROM AUTHOR]

More than 30 years separate the two largest oil spills in North American history (the Ixtoc I and Macondo well blowouts), yet the responses to both disasters were nearly identical in spite of advanced material innovation during the same time period. Novel, mechanically durable sorbents could enable (a) sorbent use in the open ocean, (b) automated deployment to minimize workforce exposure to toxic chemicals, and (c) mechanical recovery of spilled oils. Here, we explore the use of two mechanically durable, low-density (0.1-0.2 g cm(-3)), highly porous (85-99% porosity), hydrophobic (water contact angles >120°), flexible aerogel composite blankets as sorbent materials for automated oil capture and recovery: Cabot Thermal Wrap (TW) and Aspen Aerogels Spaceloft (SL). Uptake of crude oils (Iraq and Sweet Bryan Mound oils) was 8.0 ± 0.1 and 6.5 ± 0.3 g g(-1) for SL and 14.0 ± 0.1 and 12.2 ± 0.1 g g(-1) for TW, respectively, nearly twice as high as similar polyurethane- and polypropylene-based devices. Compound-specific uptake experiments and discrimination against water uptake suggested an adsorption-influenced sorption mechanism. Consistent with that mechanism, chemical extraction oil recoveries were 95 ± 2 (SL) and 90 ± 2% (TW), but this is an undesirable extraction route in decentralized oil cleanup efforts. In contrast, mechanical extraction routes are favorable, and a modest compression force (38 N) yielded 44.7 ± 0.5% initially to 42.0 ± 0.4% over 10 reuse cycles for SL and initially 55.0 ± 0.1% for TW, degrading to 30.0 ± 0.2% by the end of 10 cycles. The mechanical integrity of SL deteriorated substantially (800 ± 200 to 80 ± 30 kPa), whereas TW was more robust (380 ± 80 to 700 ± 100 kPa) over 10 uptake-and-compression extraction cycles.