An efficient method of preparing Si-Fe-Al-Ca alloy from coal gasification fine slag via plasma smelting and alternating current magnetic field.

It is of great significance to solve the environmental problems caused by the unreasonable treatment of coal gasification slag. This study successfully produced Si-Fe-Al-Ca alloy from low-carbon fine slag with petroleum coke as reducing agent in a plasma furnace with an alternating current magnetic field, which solved the problem of the high reactivity requirement of carbon reductant for plasma smelting. The optimum carbon content of the mixed low-carbon fine slag and petroleum coke is 105% of the theoretical value. As the strength of the alternating current magnetic field increased (from 0% to 100% of the maximum power), the yield of the alloy (from 25.46% to 58.19%) and the recovery ratios of each element (Si, Fe, Al, Ca, Ti) increased. In addition, as the magnetic field strength increased, the pores inside the alloy became smaller, the composition of the alloy became more homogeneous, and a better separation of the alloy from the slag was observed. The main composition of the alloy at the strongest alternating current magnetic field is Si: 51.14 wt%, Fe: 28.41 wt%, Al: 9.14 wt%, Ca: 7.15 wt%, Ti: 2.03 wt%. We attribute the enhanced smelting effect of the alternating current magnetic field to the resistive heat and Lorentz force produced by the induced current. In addition, the skin effect concentrated the induced current on the surface of the oxide particles and carbon particles, which increased the temperature of the reaction interface and promoted the carbothermal reduction reaction.

[Molding matrix formulation of hot-melt pressure-sensitive adhesive plaster of personalized traditional Chinese medicine preparations].

This study aims to optimize the matrix formulation for the hot-melt pressure-sensitive adhesive plaster of personalized traditional Chinese medicine(TCM) preparations and verify the applicability of the formulation. The central composite design in JMP Pro 16.1.0 was employed to optimize the dosages of styrene-isoprene-styrene triblock copolymer(SIS), hydrogenated petroleum resin, and lightweight liquid paraffin, with the fine powder of Yipifang as the model drug(drug loading of 10%) and the sensory score and objective evaluation as the comprehensive evaluation indicators. The quality evaluation system of hot-melt pressure-sensitive adhesive plaster of personalized TCM preparations was established. The applicability of the optimized matrix formulation of hot-melt pressure-sensitive adhesive plaster was verified with 16 TCM preparations for external application. Furthermore, the applicability of the matrix formulation was investigated with different drug loadings. The general molding matrix formulation was SIS∶hydrogenated petroleum resin∶lightweight liquid paraffin 3∶3∶5. The optimized matrix formulation showed good molding properties and high quality scores for 16 TCM preparations and were suitable for the plastering of finely powdered decoction pieces with a loading capacity of 10% to 30%. The results suggest that the optimized matrix formulation has good applicability and is suitable for TCM preparations. The findings lay a foundation for the application and promotion of the hot-melt pressure-sensitive adhesive plasters of personalized TCM preparations.

Phenotypic and genetic characterization of a lipolytic Ralstonia mannitolilytica isolate from petroleum-contaminated soil in Iraq.

BACKGROUND: Lipases play a crucial role in various industrial applications, and microbial lipases, particularly those from bacteria, possess significant properties. With increasing concerns about the environmental and health impacts of hydrocarbons from pipelines and refineries, there is a growing need to mitigate the risks associated with these compounds. METHODS: In this study, 40 bacterial isolates were recovered from contaminated soil samples collected from multiple refineries across Iraq. Using the Vitek system, bacterial isolates were identified up to the species level, revealing that only 12 isolates exhibited lipase-producing capabilities. RESULTS: Among the lipase-producing isolates, Ralstonia mannitolilytica demonstrated the highest extracellular lipase activity, as determined by an olive oil plate assay supplemented with rhodamine B. Confirmation of the species identity was achieved through 16S rRNA gene sequencing, with the obtained sequence deposited under accession number LC772176.1. Further sequence analysis revealed single nucleotide polymorphisms (SNPs) in the genome of Ralstonia mannitolilytica strain H230303-10_N19_7x_R2 (CP011257.1, positions 1,311,102 and 1,311,457). Additionally, the presence of the lipase gene was confirmed through amplification and sequencing using a thermocycler PCR. Sequence analysis of the gene, aligned using Geneious Prime software, identified SNPs (CP010799, CP049132, AY364601, CP011257, and CP023537), and a phylogenetic tree was constructed based on genetic characterization. CONCLUSION: Our findings highlight the potential of Ralstonia mannitolilytica as a promising candidate for lipase production and contribute to our understanding of its genetic diversity and biotechnological applications in hydrocarbon degradation and industrial processes.

Nitrate and oxygen significantly changed the abundance rather than structure of sulphate-reducing and sulphur-oxidising bacteria in water retrieved from petroleum reservoirs.

Sulphate-reducing bacteria (SRB) are the main culprits of microbiologically influenced corrosion in water-flooding petroleum reservoirs, but some sulphur-oxidising bacteria (SOB) are stimulated when nitrate and oxygen are injected, which control the growth of SRB. This study aimed to determine the distributions of SRB and SOB communities in injection-production systems and to analyse the responses of these bacteria to different treatments involving nitrate and oxygen. Desulfovibrio, Desulfobacca, Desulfobulbus, Sulfuricurvum and Dechloromonas were commonly detected via 16S rRNA gene sequencing. Still, no significant differences were observed for either the SRB or SOB communities between injection and production wells. Three groups of water samples collected from different sampling sites were incubated. Statistical analysis of functional gene (dsrB and soxB) clone libraries and quantitative polymerase chain reaction showed that the SOB community structures were more strongly affected by the nitrate and oxygen levels than SRB clustered according to the sampling site; moreover, both the SRB and SOB community abundances significantly changed. Additionally, the highest SRB inhibitory effect and the lowest dsrB/soxB ratio were obtained under high concentrations of nitrate and oxygen in the three groups, suggesting that the synergistic effect of nitrate and oxygen level was strong on the inhibition of SRB by potential SOB.

Break oily water emulsion during petroleum enhancing production processes using green approach for the synthesis of SnCuO@FeO nanocomposite from microorganisms.

The aim of this work was to synthesize a green nanoparticle SnCuO@FeO nanocomposite core-shell to break oily water emulsions during petroleum-enhancing production processes as an alternative to chemical and physical processes. In this study, eight bacterial isolates (MHB1-MHB8) have been isolated from tree leaves, giant reeds, and soil samples. The investigation involved testing bacterial isolates for their ability to make FeO nanoparticles and choosing the best producers. The selected isolate (MHB5) was identified by amplification and sequencing of the 16S rRNA gene as Bacillus paramycoides strain OQ878685. MHB5 produced the FeO nanoparticles with the smallest particle size (78.7 nm) using DLS. XRD, FTIR, and TEM were used to characterize the biosynthesized nanoparticles. The jar experiment used SnCuO@FeO with different ratios of Sn to CuO (1:1, 2:1, and 3:1) to study the effect of oil concentration, retention time, and temperature. The most effective performance was observed with a 1:1 ratio of Sn to CuO, achieving an 85% separation efficiency at a concentration of 5 mg/L, for a duration of 5 min, and at a temperature of 373 K. Analysis using kinetic models indicates that the adsorption process can be accurately described by both the pseudo-first-order and pseudo-second-order models. This suggests that the adsorption mechanism likely involves a combination of film diffusion and intraparticle diffusion. Regarding the adsorption isotherm, the Langmuir model provides a strong fit for the data, while the D-R model indicates that physical interactions primarily govern the adsorption mechanism. Thermodynamic analysis reveals a ∆H value of 18.62 kJ/mol, indicating an exothermic adsorption process. This suggests that the adsorption is a favorable process, as energy is released during the process. Finally, the synthesized green SnCuO@FeO nanocomposite has potential for use in advanced applications in the oil and gas industry to help the industry meet regulatory compliance, lower operation costs, reduce environmental impact, and enhance production efficiency.

Synergistic algal/bacterial interaction in membrane bioreactor for detoxification of 1,2-dichloroethane-rich petroleum wastewater.

The study addressed the challenge of treating petroleum industry wastewater with high concentrations of 1,2-dichloroethane (1,2-DCA) ranging from 384 to 1654 mg/L, which poses a challenge for bacterial biodegradation and algal photodegradation. To overcome this, a collaborative approach using membrane bioreactors (MBRs) that combine algae and bacteria was employed. This synergistic method effectively mitigated the toxicity of 1,2-DCA and curbed MBR fouling. Two types of MBRs were tested: one (B-MBR) used bacterial cultures and the other (AB-MBR) incorporated a mix of algal and bacterial cultures. The AB-MBR significantly contributed to 1,2-DCA removal, with algae accounting for over 20% and bacteria for approximately 49.5% of the dechlorination process. 1,2-DCA metabolites, including 2-chloroethanol, 2-chloro-acetaldehyde, 2-chloroacetic acid, and acetic acid, were partially consumed as carbon sources by algae. Operational efficiency peaked at a 12-hour hydraulic retention time (HRT) in AB-MBR, enhancing enzyme activities crucial for 1,2-DCA degradation such as dehydrogenase (DH), alcohol dehydrogenase (ADH), and acetaldehyde dehydrogenase (ALDH). The microbial diversity in AB-MBR surpassed that in B-MBR, with a notable increase in Proteobacteria, Bacteroidota, Planctomycetota, and Verrucomicrobiota. Furthermore, AB-MBR showed a significant rise in the dominance of 1,2-DCA-degrading genus such as Pseudomonas and Acinetobacter. Additionally, algal-degrading phyla (e.g., Nematoda, Rotifera, and Streptophyta) were more prevalent in AB-MBR, substantially reducing the issue of membrane fouling.

A co-type ductile film with high tensile strength and fast self-healing properties for shaped fruit preservation.

Traditional petroleum-based plastics have high energy consumption, require professional equipment, are non-degradable after use, and lack antibacterial properties, making it impossible to achieve long-lasting freshness in fruits and vegetables. Herein, we report a novel co-type film-forming method with low energy consumption and without production equipment, which uses PVA-borax gel as a substrate and adds a certain proportion of CMC and TA to prepare multifunctional CMC/TA@PVA-borax composite hydrogels (CTPB). The dynamic borax ester bonding and hydrogen bonding in the CTPB hydrogel results in an ultra-high tensile strength of more than 5500% and rapid self-healing within 8 s. Interestingly, hydrogels can be arbitrarily shaped and stretched like play dough and thus can be stretched into ductile films by co-type film formation. The antimicrobial properties of the hydrogel film can be attributed to the synergistic effects of TA and borax. The mussel structure of TA allows the hydrogel film to adhere directly to different surfaces for more effective bacterial killing. In addition, the hydrogel film has a high level of biosafety and biodegradability and shows good performance in fruit storage. This study provides a convenient and low-energy method for the preparation of films, which in part reduces the increasing environmental pollution caused by petroleum-based plastics.

Phytoremediation of pollutants in oil-contaminated soils by Alhagi camelorum: evaluation and modeling.

Phytoremediation is a cost-effective and environmentally friendly method, offering a suitable alternative to chemical and physical approaches for the removal of pollutants from soil. This research explored the phytoremediation potential of Alhagi camelorum, a plant species, for total petroleum hydrocarbons (TPHs) and heavy metals (HMs), specifically lead (Pb), chromium (Cr), nickel (Ni), and cadmium (Cd), in oil-contaminated soil. A field-scale study spanning six months was conducted, involving the cultivation of A. camelorum seeds in a nursery and subsequent transplantation of seedlings onto prepared soil plots. Control plots, devoid of any plants, were also incorporated for comparison. Soil samples were analyzed throughout the study period using inductively coupled plasma-optical emission spectroscopy (ICP‒OES) for HMs and gas chromatography‒mass spectrometry (GC‒MS) for TPHs. The results showed that after six months, the average removal percentage was 53.6 ± 2.8% for TPHs and varying percentages observed for the HMs (Pb: 50 ± 2.1%, Cr: 47.6 ± 2.5%, Ni: 48.1 ± 1.6%, and Cd: 45.4 ± 3.5%). The upward trajectory in the population of heterotrophic bacteria and the level of microbial respiration, in contrast to the control plots, suggests that the presence of the plant plays a significant role in promoting soil microbial growth (P < 0.05). Moreover, kinetic rate models were examined to assess the rate of pollutant removal. The coefficient of determination consistently aligned with the first-order kinetic rate model for all the mentioned pollutants (R2 > 0.8). These results collectively suggest that phytoremediation employing A. camelorum can effectively reduce pollutants in oil-contaminated soils.

Spatial distribution characteristics and degradation mechanism of microorganisms in n-hexadecane contaminated vadose zone.

The damage caused by petroleum hydrocarbon pollution to soil and groundwater environment is becoming increasingly significant. The vadose zone is the only way for petroleum hydrocarbon pollutants to leak from surface into groundwater. The spatial distribution characteristics of indigenous microorganisms in vadose zone, considering presence of capillary zones, have rarely been reported. To explore the spatial distribution characteristics of indigenous microorganisms in vadose zone contaminated by petroleum hydrocarbons, a one-dimensional column migration experiment was conducted using n-hexadecane as characteristic pollutant. Soil samples were collected periodically from different heights during experiment. Corresponding environmental factors were monitored online. The microbial community structure and spatial distribution characteristics of the cumulative relative abundance were systematically analyzed using 16S rRNA sequencing. In addition, the microbial degradation mechanism of n-hexadecane was analyzed using metabolomics. The results showed that presence of capillary zone had a strong retarding effect on n-hexadecane infiltration. Leaked pollutants were mainly concentrated in areas with strong capillary action. Infiltration and displacement of NAPL-phase pollutants were major driving force for change in moisture content (θ) and electric conductivity (EC) in vadose zone. The degradation by microorganisms results in a downward trend in potential of hydrogen (pH) and oxidation-reduction potential (ORP). Five petroleum hydrocarbon-degrading bacterial phyla and 11 degradable straight-chain alkane bacterial genera were detected. Microbial degradation was strong in the area near edge of capillary zone and locations of pollutant accumulation. Mainly Sphingomonas and Nocardioides bacteria were involved in microbial degradation of n-hexadecane. Single-end oxidation involved microbial degradation of n-hexadecane (C16H34). The oxygen consumed, hexadecanoic acid (C16H32O2) produced during this process, and release of hydrogen ions (H+) were the driving factors for reduction of ORP and pH. The vadose zone in this study considered presence of capillary zone, which was more in line with actual contaminated site conditions compared with previous studies. This study systematically elucidated vertical distribution characteristics of petroleum hydrocarbon pollutants and spatiotemporal variation characteristics of indigenous microorganisms in vadose zone considered presence of capillary zone. In addition, the n-hexadecane degradation mechanism was elucidated using metabolomics. This study provides theoretical support for development of natural attenuation remediation measures for petroleum-hydrocarbon-contaminated soil and groundwater.

A novel bioprospecting strategy via 13C-based high-throughput probing of active methylotrophs inhabiting oil reservoir surface soil.

Methane-oxidizing bacteria (MOB) have long been considered as a microbial indicator for oil and gas prospecting. However, due to the phylogenetically narrow breath of ecophysiologically distinct MOB, classic culture-dependent approaches could not discriminate MOB population at fine resolution, and accurately reflect the abundance of active MOB in the soil above oil and gas reservoirs. Here, we presented a novel microbial anomaly detection (MAD) strategy to quantitatively identify specific indicator methylotrophs in the surface soils for bioprospecting oil and gas reservoirs by using a combination of 13C-DNA stable isotope probing (SIP), high-throughput sequencing (HTS), quantitative PCR (qPCR) and geostatistical analysis. The Chunguang oilfield of the Junggar Basin was selected as a model system in western China, and type I methanotrophic Methylobacter was most active in the topsoil above the productive oil wells, while type II methanotrophic Methylosinus predominated in the dry well soils, exhibiting clear differences between non- and oil reservoir soils. Similar results were observed by quantification of Methylobacter pmoA genes as a specific bioindicator for the prediction of unknown reservoirs by grid sampling. A microbial anomaly distribution map based on geostatistical analysis further showed that the anomalous zones were highly consistent with petroleum, geological and seismic data, and validated by subsequent drilling. Over seven years, a total of 24 wells have been designed and drilled into the targeted anomaly, and the success rate via the MAD prospecting strategy was 83 %. Our results suggested that molecular techniques are powerful tools for oil and gas prospecting. This study indicates that the exploration efficiency could be significantly improved by integrating multi-disciplinary information in geophysics and geomicrobiology while reducing the drilling risk to a greater extent.

Performance evaluation of rhamnolipid biosurfactant produced by Pseudomonas aeruginosa and its effect on marine oil-spill remediation.

This study aimed to reveal that the effect of biosurfactant on the dispersion and degradation of crude oil. Whole genome analysis showed that Pseudomonas aeruginosa GB-3 contained abundant genes involved in biosurfactant synthesis and metabolic processes and had the potential to degrade oil. The biosurfactant produced by strain GB-3 was screened by various methods. The results showed that the surface tension reduction activity was 28.6 mN·m-1 and emulsification stability was exhibited at different pH, salinity and temperature. The biosurfactant was identified as rhamnolipid by LC-MS and FTIR. The fermentation conditions of strain GB-3 were optimized by response surface methodology, finally the optimal system (carbon source: glucose, nitrogen source: ammonium sulfate, C/N ratio:16:1, pH: 7, temperature: 30-35 °C) was determined. Compared with the initial fermentation, the yield of biosurfactant increased by 4.4 times after optimization. In addition, rhamnolipid biosurfactant as a dispersant could make the dispersion of crude oil reach 38% within seven days, which enhanced the bioavailability of crude oil. As a biostimulant, it could also improve the activity of indigenous microorganism and increase the degradation rate of crude oil by 10-15%. This study suggested that rhamnolipid biosurfactant had application prospect in bioremediation of marine oil-spill.

Broad-spectrum hydrocarbon-degrading microbes in the global ocean metagenomes.

Understanding the diversity and functions of hydrocarbon-degrading microorganisms in marine environments is crucial for both advancing knowledge of biogeochemical processes and improving bioremediation methods. In this study, we leveraged nearly 20,000 metagenome-assembled genomes (MAGs), recovered from a wide array of marine samples across the global oceans, to map the diversity of aerobic hydrocarbon-degrading microorganisms. A broad bacterial diversity was uncovered, with a notable preference for degrading aliphatic hydrocarbons over aromatic ones, primarily within Proteobacteria and Actinobacteriota. Three types of broad-spectrum hydrocarbon-degrading bacteria were identified for their ability to degrade various hydrocarbons and possession of multiple copies of hydrocarbon biodegradation genes. These bacteria demonstrate extensive metabolic versatility, aiding their survival and adaptability in diverse environmental conditions. Evidence of gene duplication and horizontal gene transfer in these microbes suggested a potential enhancement in the diversity of hydrocarbon-degrading bacteria. Positive correlations were observed between the abundances of hydrocarbon-degrading genes and environmental parameters such as temperature (-5 to 35 °C) and salinity (20 to 42 PSU). Overall, our findings offer valuable insights into marine hydrocarbon-degrading microorganisms and suggest considerations for selecting microbial strains for oil pollution remediation.

Do renewable energy sources perfectly displace non-renewable energy sources? Evidence from Asia-Pacific economies.

The existing scholarly discourse surrounding the energy transition has long operated on the assumption of perfect displacement of non-renewable energy. However, an evolving set of studies highlights an intricate web of inefficiencies and complexities that prevent the perfect displacement of fossil fuel energy with renewable energy production. Since this could carry serious implications for the environmental targets of several economies, it is crucial to accurately and continuously measure the actual extent of fossil fuel displacement. Within this framework, this study empirically investigates the extent of non-renewable energy displacement by renewable energy for a balanced panel of seven Asia-Pacific (APAC) countries between 1989 and 2015. The outcome function also controls for globalisation, real GDP per capita, and crude oil prices. After implementing the necessary diagnostics, the panel cointegration establishes a significant long-run relationship among the selected variables. The PMG-ARDL estimation indicates that renewable energy production and globalisation significantly reduce the fossil fuel energy production, whereas real GDP per capita and crude oil prices induce it positively. However, the coefficient of renewable energy production is only - 0.39, indicating that more than 2.5 units of renewable electricity are necessary to displace a unit of non-renewable energy. As such, this study concludes that the current energy transition in Asia-Pacific region is not perfect. These results are robust to the usage of the FGLS estimation technique. The study suggests the adoption of a new energy transition that allows greater displacement of fossil fuel energy as well as gradual reduction in overall energy use.

The application of laser­induced fluorescence in oil spill detection.

Over the past two decades, oil spills have been one of the most serious ecological disasters, causing massive damage to the aquatic and terrestrial ecosystems as well as the socio-economy. In view of this situation, several methods have been developed and utilized to analyze oil samples. Among these methods, laser-induced fluorescence (LIF) technology has been widely used in oil spill detection due to its classification method, which is based on the fluorescence characteristics of chemical material in oil. This review systematically summarized the LIF technology from the perspective of excitation wavelength selection and the application of traditional and novel machine learning algorithms to fluorescence spectrum processing, both of which are critical for qualitative and quantitative analysis of oil spills. It can be seen that an appropriate excitation wavelength is indispensable for spectral discrimination due to different kinds of polycyclic aromatic hydrocarbons' (PAHs) compounds in petroleum products. By summarizing some articles related to LIF technology, we discuss the influence of the excitation wavelength on the accuracy of the oil spill detection model and proposed several suggestions on the selection of excitation wavelength. In addition, we introduced some traditional and novel machine learning (ML) algorithms and discussed the strengths and weaknesses of these algorithms and their applicable scenarios. With an appropriate excitation wavelength and data processing algorithm, it is believed that laser-induced fluorescence technology will become an efficient technique for real-time detection and analysis of oil spills.

Carbon reduction attention and financial market stress: A network spillover analysis based on quantile VAR modeling.

As climate change intensifies, attention to the issue of carbon emission reduction has gradually increased. This research constructs a complete set of indicators of carbon reduction attention and financial market stress and applies the quantile VAR method to calculate the volatility spillover between carbon reduction attention and financial market stress. We conclude with the following. Firstly, a relatively close volatility spillover association exists between carbon reduction attention and financial market stress. In the research system, carbon reduction attention mainly assumes the role of information receiver. Additionally, when examining the spillover status in different quantiles, the total spillover level shows an irregular "bowl" structure, while the net spillover level of each variable has different shapes. Secondly, the dynamic spillover level in the extreme quantile condition maintains a connectivity range of 60-80%, significantly higher than that of the median condition. Finally, this study finds two sets of significant complementary spillovers within the system, namely, "carbon reduction attention - crude oil market stress" and "stock market stress - real estate market stress", which provide investors with an opportunity to explore the potential of the carbon reduction attention and real estate market stress in the future.

The toxic effects of petroleum pollutants to microalgae in marine environment.

Marine oil pollution is one of the major global environmental pollution problems. Marine microalgae are the foundation of the marine food chain, providing the main primary productivity of the ocean. They not only maintain the energy flow and material cycle of the entire marine ecosystem, but also play an important role in regulating global climate change. Exploring the impact of petroleum pollutants on marine microalgae is extremely important for studying marine environmental pollution. This review first introduced the sources, compositions, and forms of petroleum pollutants and their migration and transformation processes in the ocean. Then, the toxic effects of petroleum pollutants on marine microalgae were summarized. The growth of marine microalgae showed low-concentration promotion and high-concentration inhibition. The population growth and interspecific relationships of marine microalga was changed and the photosynthesis of marine microalgae was influenced. Finally, potential research directions and suggestions for marine microalgae in the future were proposed.

Surface active dicationic ionic liquids as green oil spill dispersants.

The utilization of chemical dispersants as a way of mitigating of oil spills in marine eco-system has been extensively documented worldwide. Hence, in this research we have successfully synthesized two amphiphilic asymmetric Dicaionic Ionic Liquids (DILs). The efficacy of these synthesized DILs as dispersants was assessed using the baffled flask test (BFT). The results indicated a dispersant effectiveness ranging from 47.98 % to 79.76 % for the dispersion of heavy crude oil across various temperature ranges (10-30 °C). These dispersant-to-oil ratios (DOR) were maintained at 3: 100 (V%), showcasing promising dispersant capabilities for mitigating heavy crude oil spills. Additionally, acute toxicity tests conducted on Nile tilapia and Oreochromis niloticus have demonstrated the relatively low toxicity of the IL-dispersants, with Lethal Concentration 50 (LC50) values exceeding 100 ppm after 96 h. This suggests a practically slight toxic effect on the tested fish. In summary, the newly developed IL-dispersants are considered to be conducive to environmentally benign oil spill remediation.

Unlocking bioremediation potential for site restoration: A comprehensive approach for crude oil degradation in agricultural soil and phytotoxicity assessment.

Crude oil contamination has inflicted severe damage to soil ecosystems, necessitating effective remediation strategies. This study aimed to compare the efficacy of four different techniques (biostimulation, bioaugmentation, bioaugmentation + biostimulation, and natural attenuation) for remediating agricultural soil contaminated with crude oil using soil microcosms. A consortium of previously characterized bacteria Xanthomonas boreopolis, Microbacterium schleiferi, Pseudomonas aeruginosa, and Bacillus velezensis was constructed for bioaugmentation. The microbial count for the constructed consortium was recorded as 2.04 ± 0.11 × 108 CFU/g on 60 d in augmented and stimulated soil samples revealing their potential to thrive in chemically contaminated-stress conditions. The microbial consortium through bioaugmentation + biostimulation approach resulted in 79 ± 0.92% degradation of the total polyaromatic hydrocarbons (2 and 3 rings âˆ¼ 74%, 4 and 5 rings âˆ¼ 83% loss) whereas, 91 ± 0.56% degradation of total aliphatic hydrocarbons (C8-C16 ∼ 90%, C18-C28 ∼ 92%, C30 to C40 ∼ 88% loss) was observed in 60 d. Further, after 60 d of microcosm treatment, the treated soil samples were used for phytotoxicity assessment using wheat (Triticum aestivum), black chickpea (Cicer arietinum), and mustard (Brassica juncea). The germination rates for wheat (90%), black chickpea (100%), and mustard (100%) were observed in 7 d with improved shoot-root length and biomass in both bioaugmentation and biostimulation approaches. This study projects a comprehensive approach integrating bacterial consortium and nutrient augmentation strategies and underscores the vital role of innovative environmental management practices in fostering sustainable remediation of oil-contaminated soil ecosystems. The formulated bacterial consortium with a nutrient augmentation strategy can be utilized to restore agricultural lands towards reduced phytotoxicity and improved plant growth.

Bioremediation of oily hypersaline soil via autochthonous bioaugmentation with halophilic bacteria and archaea.

Kuwaiti hypersaline soil samples were contaminated with 5 % (w/w) weathered Kuwaiti light crude oil and bioaugmented with autochthonous halophilic hydrocarbonoclastic archaeal and bacterial strains, two each, individually and as consortia. Residual oil contents were determined, and microbial communities were analyzed by culture-dependent and culture-independent approaches initially and seasonally for one year. After one year of the bioremediation process, the mean oil degradation rate was similar across all treated soils including the controlled unbioaugmented one. Oil hydrocarbons were drastically reduced in all soil samples with values ranging from 82.7 % to 93 %. During the bioremediation process, the number of culturable oil-degrading bacteria increased to a range of 142 to 344 CFUx104 g-1 after 12 months of bioaugmentation. Although culture-independent analysis showed a high proportion of inoculants initially, none could be cultured throughout the bioremediation procedure. Within a year, microbial communities changed continually, and 33 species of halotolerant/halophilic hydrocarbonoclastic bacteria were isolated and identified belonged mainly to the three major bacterial phyla Actinobacteria, Proteobacteria, and Firmicutes. The archaeal phylum Halobacterota represented <1 % of the microbial community's relative abundance, which explains why none of its members were cultured. Improving the biodegradability of an already balanced environment by autochthonous bioaugmentation is more involved than just adding the proper oil degraders. This study emphasizes the possibility of a relatively large resistant population, a greater diversity of oil-degrading microorganisms, and the highly selective impacts of oil contamination on hypersaline soil bacterial communities.

Effects of biochar immobilization of Serratia sp. F4 OR414381 on bioremediation of petroleum contamination and bacterial community composition in loess soil.

Petroleum hydrocarbons pose a significant threat to human health and the environment. Biochar has increasingly been utilized for soil remediation. This study investigated the potential of biochar immobilization using Serratia sp. F4 OR414381 for the remediation of petroleum-contaminated soil through a pot experiment conducted over 90 days. The treatments in this study, denoted as IMs (maize straw biochar-immobilized Serratia sp. F4), degraded 82.5% of the total petroleum hydrocarbons (TPH), 59.23% of the aromatic, and 90.1% of the saturated hydrocarbon fractions in the loess soils. During remediation, the soil pH values decreased from 8.76 to 7.33, and the oxidation-reduction potential (ORP) increased from 156 to 229 mV. The treatment-maintained soil nutrients of the IMs were 138.94 mg/kg of NO3- -N and 92.47 mg/kg of available phosphorus (AP), as well as 11.29% of moisture content. The activities of soil dehydrogenase (SDHA) and catalase (CAT) respectively increased by 14% and 15 times compared to the CK treatment. Three key petroleum hydrocarbon degradation genes, including CYP450, AJ025, and xylX were upregulated following IMs treatment. Microbial community analysis revealed that a substantial microbial population of 1.01E+ 09 cells/g soil and oil-degrading bacteria such as Salinimicrobium, Saccharibacteria_genera_incertae_sedis, and Brevundimonas were the dominant genera in IMs treatment. This suggests that the biochar immobilized on Serratia sp. F4 OR414381 improves soil physicochemical properties and enhances interactions among microbial populations, presenting a promising and environmentally friendly approach for the stable and efficient remediation of petroleum-contaminated loess soil.