Recent trends in polycyclic aromatic hydrocarbons pollution distribution and counteracting bio-remediation strategies

Transforming beef quality through healthy breeding: a strategy to reduce carcinogenic compounds and enhance human health: a review

The presence of carcinogenic substances in beef poses a significant risk to public health, with far-reaching implications for consumer safety and the meat production industry. Despite advancements in food safety measures, traditional breeding methods have proven inadequate in addressing these risks, revealing a substantial gap in knowledge. This review aims to fill this gap by evaluating the potential of healthy breeding techniques to significantly reduce the levels of carcinogenic compounds in beef. We focus on elucidating the molecular pathways that contribute to the formation of key carcinogens, such as heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), while exploring the transformative capabilities of advanced genomic technologies. These technologies include genomic selection, CRISPR/Cas9, base editing, prime editing, and artificial intelligence-driven predictive models. Additionally, we examine multi-omics approaches to gain new insights into the genetic and environmental factors influencing carcinogen formation. Our findings suggest that healthy breeding strategies could markedly enhance meat quality, thereby offering a unique opportunity to improve public health outcomes. The integration of these innovative technologies into breeding programs not only provides a pathway to safer beef production but also fosters sustainable livestock management practices. The improvement of these strategies, along with careful consideration of ethical and regulatory challenges, will be crucial for their effective implementation and broader impact.

Organic pollutants in a large shallow lake, and the potential of the local quagga mussel population for their removal

Filter feeders, like mussels, can significantly lower the concentration of harmful substances in the water body. In the present study, we examined the distribution of organic pollutants (polycyclic aromatic hydrocarbons [PAHs], non-steroidal anti-inflammatory drugs [NSAIDs]) in Lake Balaton, the largest shallow lake of Central Europe. We also investigated the sensitivity of the invasive quagga mussel to these substances and its potential to reduce their concentration in the water column. Our findings show that organic pollutant levels in Lake Balaton were generally below concentrations known to harm mussels, as indicated by the stress gene activity patterns observed along the lake's longitudinal axis. However, in the most urbanized eastern part of the lake, especially in spring, we detected signs of environmental contamination from certain pollutants (e.g. diclofenac), highlighting potential risks to local ecosystems and communities. Removal capacity of the mussels for PAHs reached the maximum after four days of exposure to 5-10 % diluted water accommodated fraction of fuel-oil fraction #4 when the mussels (20 ind. L-1) reduced the PAH level by 100-85 %. Mussels (50 ind. L-1) removed 28 % and 21 % of ibuprofen and ketoprofen, respectively, from 1 µg L-1 concentrated solutions within 24 h. Many of the stress response genes were activated in the quagga mussel after their exposure to PAHs. These results suggest a significant role of gregarious invasive bivalves in the removal of organic pollutants from lake water.

Population dynamics of a bacterial consortium from a marine sediment of the Gulf of Mexico during biodegradation of the aromatic fraction of heavy crude oil

In the marine environment, uncontained crude oil is dispersed and degraded by abiotic or biotic processes; native bacterial populations gradually adapt to integrate interspecific and intraspecific metabolic networks for efficient and dynamic utilization of xenobiotic substrates as carbon source. Aromatic compounds accumulate in marine sediments and bacterial populations at these sites play a crucial role in the mobilization of those complex molecules into the global geochemical cycles. The aim of this work was to use native bacteria from a marine sediment sample in the Gulf of Mexico to enhance the biodegradation of the aromatic fraction from a heavy crude oil, as the sole carbon source, during a 200-day microcosm experiment. This process involved the gradual increase of the aromatic fraction into the culture to promote bacterial enrichment; the increase in viable cells correlated well with a biodegradation pattern of the aromatic fraction at some points. Bacterial biodiversity, as revealed by metagenomic and microbiological approaches, indicates that bacterial groups are present at all fraction concentrations, but with changes in abundance, richness and dominance. Population dynamics revealed the presence of bacteria that modify emulsification and surface tension reduction values, which could promote the incorporation of the highly hydrophobic polyaromatic compounds into the culture aqueous phase for their biodegradation by hydrocarbonoclastic bacteria present. On the other hand, the presence of non-hydrocarbonoclastic bacteria probably is sustained by cross-feeding events involving sugars, amino acids, short carbon compounds, lipids produced by the former bacteria by co-metabolism of complex aromatic substrates, which are transformed into diverse biomolecules for biofilm development to promote a bacterial population dynamics adapted to this environment.

Plasmid Backbone Impacts Conjugation Rate, Transconjugant Fitness, and Community Assembly of Genetically Bioaugmented Soil Microbes for PAH Bioremediation

Many polycyclic aromatic hydrocarbons (PAHs) in the environment resulting from crude oil spills and the incomplete combustion of organic matter are highly toxic, mutagenic, or carcinogenic to microorganisms and humans. Bioremediation of PAHs using microorganisms that encode biodegradative genes is a promising approach for environmental PAH cleanup. However, the viability of exogenous microorganisms is often limited due to competition with the native microbial community. Instead of relying on the survival of one or a few species of bacteria, genetic bioaugmentation harnesses conjugative plasmids that spread functional genes to native microbes. In this study, two plasmid backbones that differ in copy number regulation, replication, and mobilization genes were engineered to contain a PAH dioxygenase gene (bphC) and conjugated to soil bacteria including Bacillus subtilis, Pseudomonas putida, and Acinetobacter sp., as well as a synthetic community assembled from these bacteria. Fitness effects of the plasmids in transconjugants significantly impacted the rates of conjugative transfer and biotransformation rates of a model PAH (2,3-dihydroxybiphenyl). A synergistic effect was observed in which synthetic communities bioaugmented with bphC had significantly higher PAH degradation rates than bacteria grown in monocultures. Finally, conjugation rates were significantly associated with the relative abundances of bacteria in synthetic communities, underscoring how fitness impacts of plasmids can shape the microbial community structure and function.

A novel FadL family outer membrane transporter is involved in the uptake of polycyclic aromatic hydrocarbons

Gram-negative bacteria play a pivotal role in the bioremediation of persistent organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs). Because the outer membrane (OM) of these bacteria hinders the direct permeation of hydrophobic substances into the cells, trans-OM proteins are required for the uptake of PAHs. However, neither the characteristics of PAH transporters nor the specific transport mechanism has been well interpreted. In this study, we revealed the participation of a novel FadL family transporter, PadL, in the biodegradation of the representative PAH phenanthrene in Novosphingobium pentaromativorans US6-1, an efficient PAH-degrading bacterium. PadL facilitates the cross-OM transport of phenanthrene, thus upregulating the expression of the gene ahdA1e that is critical to the PAH catabolism. We then showed that hydrophobic amino acid residues in the substrate binding pockets of PadL are essential for the binding of PAHs, such as phenanthrene and benzo[a]pyrene. PadL homologs commonly exist in most of the PAH-degrading species from Sphingomonas and Novosphingobium. The characterization of PadL provided in this study holds significant potential for improving the PAH biodegradation efficiency.

IMPORTANCE

Persistent organic pollutants, including polycyclic aromatic hydrocarbons (PAHs), pose serious threats to human health, and biodegradation has been applied as an efficient strategy for PAH removal. However, due to the high hydrophobicity of PAHs, their uptake is hindered by the bacterial outer membrane, restraining degradation efficiency. The present study reveals the critical roles of a novel FadL family protein (PadL) in the biodegradation of PAHs. PadL specifically transports PAHs such as phenanthrene and benzo[a]pyrene and PadL homologs generally exist in PAH-degrading bacteria of Sphingomonas and Novosphingobium. Our findings fill the knowledge gap in the bacterial trans-membrane uptake process of PAHs and provide a future direction for enhancing the bacterial PAH bioremediation capacity.

Temperature-responsive regulation of the polycyclic aromatic hydrocarbon-degrading mesophilic bacterium Novosphingobium pentaromativorans US6-1 with a temperature adaptation system

Survivability and tolerance of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria in harsh environments, especially under varying temperatures, are a bottleneck for the effective application of in situ bioremediation. In this study, a temperature adaptation system (TAS) was constructed by combining a customized thermotolerant system with a customized cold-resistant system to realize the temperature-responsive regulation of the PAH-degrading mesophilic bacterium Novosphingobium pentaromativorans US6-1. The innovative dual-pronged TAS strategy enabled the chassis strain to effectively tackle conditions under varying temperatures, ensuring robust biological activities across a broadened temperature spectrum and exhibiting the potential to realize the high-efficiency PAH degradation of N. pentaromativorans US6-1 in in situ bioremediation. Furthermore, the temperature-responsive regulation achieved using the TAS circuit is likely promising for creating intelligent microbial cell factories and avoiding precise temperature maintenance, making it highly useful for industrial applications.IMPORTANCEEnvironmental temperature is among the extremely important factors that determine the bioactivities of pollutant-degrading microorganisms in in situ bioremediation. Effectively maintaining the survivability and tolerance of mesophilic microorganisms under harsh conditions and varying temperatures remains a challenge in the application of pollutant bioremediation. This study, for the first time, developed a temperature adaptation system by combining a customized thermotolerant system with a customized cold-resistant system to realize the temperature-responsive regulation of the polycyclic aromatic hydrocarbon (PAH)-degrading mesophilic bacterium Novosphingobium pentaromativorans US6-1, thus diminishing the need for precise temperature control in PAH bioremediation.

Innovative microbial activators for enhanced bioremediation of oil-contaminated soils: mechanistic insights

This paper developed an efficient microbial activator formula and conducted an in-depth study on its efficacy and mechanism in promoting the degradation of petroleum hydrocarbons in oil-contaminated soil. A 60-day microbial remediation experiment conducted on oily soil revealed that the microbial activators significantly boosted the activities of dehydrogenase and catalase, subsequently speeding up the degradation of petroleum hydrocarbons in the soil. The overall degradation rate reached as high as 71.23%, with the most significant degradation effect observed in asphaltenes, achieving a degradation rate of 93.98%. This was followed by aromatic hydrocarbons (90.45%), saturated hydrocarbons (84.39%), and asphaltenes (65%). Compared to traditional microbial stimulation methods, this activator demonstrated significant superiority. Microbial diversity analysis reveals that microbial activators can effectively activate microbial activity in soil targeting refractory petroleum hydrocarbon components. By comparing the changes in microbial community structure before and after the addition of microbial activators, we found that the activators promoted an increase in the abundance of microorganisms belonging to the Bacillota, Pseudomonadota, and Bacteroidetes, which have petroleum hydrocarbon degradation functions, and facilitated the evolution of microbial community structure towards a direction more conducive to petroleum hydrocarbon degradation. KEGG metabolic pathway analysis revealed that the degradation pathways for alkanes, aromatic hydrocarbons, and PAHs are primarily present in these bacterial phylum. This research not only clarifies the degradation mechanism but also supports future bioremediation efforts.

Which bioturbation is more likely to cause desorption of polycyclic aromatic hydrocarbons (PAHs) from sediments: Sandworms or crabs?

In this study, the effects of bioturbation induced by sandworms and crabs on polycyclic aromatic hydrocarbons (PAHs) desorption from sediments were investigated through microcosm experiments and fugacity fraction calculations, with a focus on phenanthrene (Phe), pyrene (Pyr), and benzo[a]pyrene (BaP) as representative compounds. The results indicate that crab-induced bioturbation leads to PAHs desorption rates that are 2.63 to 3.52 times higher than those observed with sandworm activity. Crabs typically forage by overturning surface sediments, whereas sandworms excavate burrows downward and exert less impact on the surface sediment integrity. Interestingly, with increasing organism density, bioturbation from sandworms inhibit the PAHs desorption, whereas crab-induced bioturbation consistently enhanced PAHs desorption rates. Fugacity fraction calculations demonstrate that the trend of desorption was the greatest for Phe, followed by Pyr, and smallest for BaP, which highlights that larger molecular weights correlate with stronger hydrophobicity and more difficulty in desorption. This study provides valuable insights into the desorption mechanisms and transport dynamics of PAHs.

Exploring Novel Fungal-Bacterial Consortia for Enhanced Petroleum Hydrocarbon Degradation

Bioremediation, involving the strategic use of microorganisms, has proven to be a cost-effective alternative for restoring areas impacted by persistent contaminants such as polycyclic aromatic hydrocarbons (PAHs). In this context, the aim of this study was to explore hydrocarbon-degrading microbial consortia by prospecting native species from soils contaminated with blends of diesel and biodiesel (20% biodiesel/80% diesel). After enrichment in a minimal medium containing diesel oil as the sole carbon source and based on 16S rRNA, Calmodulin and β-tubulin gene sequencing, seven fungi and 12 bacteria were identified. The drop collapse test indicated that all fungal and four bacterial strains were capable of producing biosurfactants with a surface tension reduction of ≥20%. Quantitative analysis of extracellular laccase production revealed superior enzyme activity among the bacterial strains, particularly for Stenotrophomonas maltophilia P05R11. Following antagonistic testing, four compatible consortia were formulated. The degradation analysis of PAHs and TPH (C5-C40) present in diesel oil revealed a significantly higher degradation capacity for the consortia compared to isolated strains. The best results were observed for a mixed bacterial-fungal consortium, composed of Trichoderma koningiopsis P05R2, Serratia marcescens P10R19 and Burkholderia cepacia P05R9, with a degradation spectrum of ≥91% for all eleven PAHs analyzed, removing 93.61% of total PAHs, and 93.52% of TPH (C5-C40). Furthermore, this study presents the first report of T. koningiopsis as a candidate for bioremediation of petroleum hydrocarbons.

Revitalization of Soil Contaminated by Petroleum Products Using Materials That Improve the Physicochemical and Biochemical Properties of the Soil

One of the key challenges in environmental protection is the reclamation of soils degraded by organic pollutants. Effective revitalization of such soils can contribute to improving the climate and the quality of feed and food, mainly by eliminating harmful substances from the food chain and by cultivating plants for energy purposes. To this end, research was carried out using two sorbents, vermiculite and agrobasalt, to detoxify soils contaminated with diesel oil and unleaded gasoline, using maize as an energy crop. The research was carried out in a pot experiment. The level of soil contamination with petroleum products was set at 8 cm3 and 16 cm3 kg-1 d.m. of soil, and the dose of the revitalizing substances, i.e., vermiculite and agrobasalt, was set at 10 g kg-1 of soil. Their effect was compared with uncontaminated soil and soil without sorbents. The obtained research results prove that both diesel oil and gasoline disrupt the growth and development of Zea mays. Diesel oil destabilized plant development more than gasoline. Both products distorted the activity of soil oxidoreductases and hydrolases, with diesel oil stimulating and gasoline inhibiting. The applied sorbents proved to be useful in the soil revitalization process, as they reduced the negative effects of pollutants on Zea mays, increased the activity of soil enzymes, enhanced the value of the biochemical soil quality indicator (BA), and improved the cation exchange capacity (CEC), the sum of exchangeable base cations (EBC), pH, and the Corg content. Agrobasalt demonstrated a greater potential for improving soil physicochemical properties, inducing an average increase in CEC and EBC values of 12% and 23%, respectively, in soil under G pressure, and by 16% and 25% in DO-contaminated soil.

Microbe-plant-nanoparticle interactions: role in bioremediation of petroleum hydrocarbons

Petroleum hydrocarbons (PHCs) are organic substances that occur naturally on earth. PHCs have emerged as one of the most prevalent and detrimental contaminants in regions comprising soil and water resources. The limitations of conventional physicochemical and biological remediation solutions could be solved by combining remediation techniques. An effective, affordable, and environmentally benign method of reducing petroleum toxins is provided by the advanced idea of bioremediation, which has evolved into nanobioremediation. Environments contaminated with PHCs have been restored through microbe-plant-nanoparticle (NP)-mediated remediation, this review emphasizes how various metallic NPs interact with microbes and plants changing both their activity and that of enzymes, therefore accelerating the remediation process. This work further examines the challenges and possible uses of nanobioremediation, as well as the application of novel technologies in the interactions between bacteria, plants, and NPs for the bioremediation of PHCs. Furthermore, it has been shown that the use of plant-based, microbe-based, microbe-plant-based, and microbe-plant-NP-based techniques to remediate contaminated soils or water bodies is economical and environmentally beneficial. Microbial consortia have been reported as the treasure houses for the cleaning and recovery of hydrocarbon-contaminated environments, and the development of technologies for bioremediation requires an understanding of hydrocarbon degradation mechanisms.

Applying kitchen compost promoted soil chrysene degradation by optimizing microbial community structure

Chrysene, as a high molecular weight polycyclic aromatic hydrocarbon (PAH), has become an important factor in degrading soil quality and constraining the safe production of food crops. Compost has been widely used to amend contaminated soil. However, to date, the main components of kitchen compost that enhance the biodegradation of chrysene in the soil remain unidentified. Thus, in this study, the enhancing effect and mechanisms of kitchen compost (KC) and kitchen compost-derived dissolved organic matter (KCOM) on chrysene removal from soil were investigated through cultivation experiments combined with high-throughput sequencing technology. Additionally, the key components influencing the degradation of chrysene were identified. The results showed that KCOM was the main component of compost that promoted the degradation of chrysene. The average degradation rate of chrysene in 1% KC- and 1% KCOM-treated soil increased by 27.20% and 24.18%, respectively, at different levels of chrysene pollution compared with the control treatment (CK). KC and KCOM significantly increased soil nutrient content, accelerated humification of organic matter, and increased microbial activity in the chrysene-contaminated soil. Correlation analyses revealed that the application of KC and KCOM optimized the microbial community by altering soil properties and organic matter structure. This optimization enhanced the degradation of soil chrysene by increasing the abundance of chrysene-degrading functional bacteria from the genera Bacillus, Arthrobacter, Pseudomonas, Lysinibacillus, and Acinetobacter. This study provides insight into the identification of key components that promote chrysene degradation and into the microbial-enhanced remediation of chrysene-contaminated soil.

PAHs contamination in ports: Status, sources and risks

Polycyclic aromatic hydrocarbons (PAHs) constitute important organic contaminants that have been degrading coastal ecosystems over the years. Evaluating PAH status in port ecosystems aligns with societal goals of maintaining clean habitats and sustainability. This comprehensive review systematically analyzed 123 articles, exploring the global distribution, sources, and ecological risks linked to PAH contamination in ports, focusing on water, sediment, and biota. The mean concentrations of 16 PAHs in water, sediment, and biota across worldwide ports were 175.63 ± 178.37 ng/L, 1592.65 ± 1836.5 μg/kg, and 268.47 ± 235.84 μg/kg, respectively. In line with PAH emissions and use in Asia, Asian ports had the highest PAH concentrations for water and biota, while African ports had the highest PAH concentrations for sediment. The temporal trend in PAH accumulation in sediments globally suggests stability. However, PAH concentrations in water and biota of global ports exhibit increasing trends, signaling aggravating PAH contamination within port aquatic ecosystems. Some ports exhibited elevated PAH levels, particularly in sediments with 4.5 %, 9.5 %, and 21 % of the ports categorized as very poor, poor, and moderate quality. Some PAH isomers exceeded guidelines, including the carcinogenic Benzo(a)pyrene (BaP). Coal, biomass, and petroleum combustion were major sources for PAHs. The structure of ports significantly influences the concentrations of PAHs. PAH concentrations in sediments of semi-enclosed ports were 3.5 times higher than those in open ports, while PAH concentrations in water and biota of semi-enclosed ports were lower than those in open ports. Finally, risk analyses conducted through Monte Carlo simulation indicated moderate to high risks to aquatic species, with probabilities of 74.8 % in water and 34.4 % in sediments of ports worldwide. This review underscores the imperative to delve deeper into the accumulation of PAHs and similar pollutants in ports for effective management and environmental protection.

Effects of different organic substrate compositions on the decontamination of aged PAH-polluted soils through outdoor co-composting

The effects of different organic substrate compositions on the efficiency of outdoor co-composting as a bioremediation technology for decontaminating soil polluted by polycyclic aromatic hydrocarbons (PAHs) were investigated. Four different substrate mixtures and two different aged PAH-contaminated soils were used in a semi-pilot-scale experiment that lasted nearly 700 days. The two soils (A and B) differed concerning both the initial concentrations of the Ʃ16 US EPA PAHs (5926 vs. 369 mg kg-1, respectively) and the type of predominant PAH group by molecular weight. The experiments revealed that while the composition of the organic substrate had an impact on the rate of PAH degradation, it did not significantly influence the final extent of PAH degradation. Notably, the organic substrate consisting of green waste and wood chips (GW) was found to facilitate the most rapid rate of PAH degradation (first-order rate constant k = 0.033 ± 0.000 d-1 with soil A over the initial 42 days of the experiment and k = 0.036 ± 0.000 d-1 with soil B over the initial 56 days). Despite the differences in organic substrate compositions and types of soil being treated, PAH degradation levels exceeded at least 95% in all the treatments after more than 680 days of co-composting. Regardless of the composition, the removal of low- and medium- molecular-weight (2-4 rings) PAHs was nearly complete by the end of the experiment. Furthermore, high-molecular-weight PAHs (5 rings and more) were significantly degraded during co-composting, with reductions ranging from 54% to 79% in soil A and from 59% to 68% in soil B. All composts were dominated by Proteobacteria, Firmicutes, and Actinobacteria, with significant differences in abundance between soils. Genera with PAH degradation potentials were detected in all samples. The results of a battery of toxicity tests showed that there was almost no toxicity associated with the final composts.

Polycyclic aromatic hydrocarbon and its adducts in peripheral blood: Gene and environment interaction among Chinese population

BACKGROUND

Benzo(a)pyrene (B[a]P) is the most widely concerned polycyclic aromatic hydrocarbons (PAHs), which metabolizes benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) in vivo to produce carcinogenic effect on the body. Currently, there is limited research on the role of the variation of metabolic enzymes in this process.

METHODS

We carried out a study including 752 participants, measured the concentrations of 16 kinds PAHs in both particle and gaseous phases, urinary PAHs metabolites, leukocyte BPDE-DNA adduct and serum BPDE- Albumin (BPDE-Alb) adduct, and calculated daily intake dose (DID) to assess the cumulative exposure of PAHs. We conducted single nucleotide polymorphism sites (SNPs) of metabolic enzymes, explored the exposure-response relationship between the levels of exposure and BPDE adducts using multiple linear regression models.

RESULT

Our results indicated that an interquartile range (IQR) increase in B[a]P, PAHs, BaPeq, 1-hydroxypyrene (1-OHP), 1-hydroxynaphthalene (1-OHNap) and 2-hydroxynaphthalene (2-OHNap) were associated with 26.53 %, 24.24 %, 28.15 %, 39.15 %, 12.85 % and 14.09 % increase in leukocyte BPDE-DNA adduct (all P < 0.05). However, there was no significant correlation between exposure with serum BPDE-Alb adduct (P > 0.05). Besides, we also found the polymorphism of CYP1A1(Gly45Asp), CYP2C9 (Ile359Leu), and UGT1A1(downstream) may affect BPDE adducts level.

CONCLUSION

Our results indicated that leukocyte BPDE-DNA adduct could better reflect the exposure to PAHs. Furthermore, the polymorphism of CYP1A1, CYP2C9 and UGT1A1affected the content of BPDE adducts.

Comparative evaluation of biodegradation of chlorpyrifos by various bacterial strains: Kinetics and pathway elucidation

The present study focused on the isolation and identification of CP and TCP bacteria degrading bacteria from the rhizospheric zone of aromatic grasses i.e. palmarosa (Cymbopogon martinii (Roxb. Wats), lemongrass (Cymbopogon flexuosus) and vetiver (Chrysopogon zizaniodes (L.) Nash.). So that these isolates alone or in combination with the vegetation of aromatic grasses will be used to clean up CP-contaminated soils. The study also explored enzymatic activities, CO2 release, dechlorination potential, and degradation pathways of bacterial strains. A total of 53 CP-tolerant bacteria were isolated on their physical characteristics and their ability to degrade CP. The ten highly CP-tolerant isolates were Pseudomonas aeruginosa Pa608, three strains of Pseudomonas hibiscicola R4-721 from different rhizosphere, Enterococcus lectis PP2a, Pseudomonas monteilii NBFPALD_RAS131, Enterobacter cloacae L3, Stenotrophomonas maltophilia PEG-390, Escherichia coli ABRL132, and Escherichia coli O104:H4 strain FWSEC0009. The CO2 emission and phosphatase activities of the isolates varied from 3.1 to 8.6 μmol mL-1 and 12.3 to 31 μmol PNP h-1, respectively in the CP medium. The degradation kinetics of CP by these isolates followed a one-phase decay model with a dissipation rate ranging from 0.048 to 0.41 d-1 and a half-life of 1.7-14.3 days. The growth data fitted in the SGompertz equation showed a growth rate (K) of 0.21 ± 0.28 to 0.91 ± 0.33 d-1. The P. monteilii strain had a faster growth rate while E. coli ABRL132 had slower growth among the isolates. The rate of TCP accumulation calculated by the SGompertz equation was 0.21 ± 0.02 to 1.18 ± 0.19 d-1. The Pseudomonas monteilii showed a lower accumulation rate of TCP. Among these, four highly effective isolates were Pseudomonas aeruginosa Pa608, Pseudomonas monteilii NBFPALD_RAS131, Stenotrophomonas maltophilia PEG-390, and Pseudomonas hibiscicola R4-721. Illustrations of the degradation pathways indicated that the difference in metabolic pathways of each isolate was associated with their growth rate, phosphatase, dehydrogenase, oxidase, and dechlorination activities.

Impact of total phenolic compounds on ecological and health risks of water and sediments from Timsah Lake, Suez Canal, Egypt

This study aimed to measure spatial and temporal distributions of total phenolic compounds and their ecological and health hazards using UV-vis spectrophotometers as a low-cost, fast, simple method in water and sediments collected from Timsah Lake, Suez Canal, Egypt, 2022. Also, assessing highly adaptive fungal species associated with contamination is designed. Due to human and environmental activities and industrial waste discharges, Timsah Lake is increasingly threatened by all kinds of pollutants. The results indicated that the seasonal concentration means of the phenolic compounds were winter (0.229) > spring (0.161) > summer (0.124) > autumn (0.131) mg/l and winter (3.08) > summer (2.66) mg/g in water and sediment samples, respectively. The result has shown that the phenol concentrations in all stations were more than 0.005 and 0.1 mg/l for Egyptian National Standards and World Health Organization (WHO) for drinking water but less than the limits of 1 mg/l for wastewater. Notably, the fungi recorded the highest counts during spring, totaling 397 colonies/100 ml of water and 842 colonies/gram of sediment. Four isolates of fungi were identified and deposited in the GenBank database by Aspergillus terreus, Aspergillus terreus, Penicillium roqueforti, and Penicillium rubens under accession numbers OR401933, OR402837, OR402878, and OR424729, respectively. Moreover, ecological risk (RQ) for the total phenolic compounds was > 1 in all investigated stations for water and sediments. The hazard quotient is HQ < 1 in all seasons in water and sediments except winter. The hazard index (HI) in water and sediments for children is higher than for adults. It can be concluded that the low-cost, fast, simple method for determining phenolic content in water and sediment samples, using UV-vis spectrophotometry, was useful for predicting the reactivates of a wide variety of phenol and their derivatives. Furthermore, it can be concluded that Periodic assessments of water quality and strict regulations are necessary to safeguard this vital resource from pollution and ensure the well-being of future generations. Finally, policymakers and water treatment specialists might use the information from this research to reduce these chemical pollutants in Egypt.

Red-emitting 4-methyl coumarin fused barbituric acid as an electrochemical sensor for catechol detection and probe for latent fingerprints

Herein, we have reported a red-emitting 4-methyl coumarin fused barbituric acid azo dye (4-MCBA) synthesized by conventional method. Density functional theory (DFT) studies of tautomer compounds were done using (B3LYP) with a basis set of 6-31G(d,p). NLO analysis has shown that tautomer has mean first-order hyperpolarisabilities (β) value of 1.8188 × 10-30 esu and 1.0470 × 10-30 esu for azo and hydrazone forms, respectively, which is approximately nine and five times greater than the magnitude of urea. 4-MCBA exhibited two absorption peaks in the range of 290-317 and 379-394 nm, and emission spectra were observed at 536 nm. CV study demonstrated that the modified 4-MCBA/MGC electrode exhibited excellent electrochemical sensitivity towards the detection of catechol and the detection limit is 9.39 μM under optimum conditions. The 4-MCBA employed as a fluorescent probe for the visualisation of LFPs on various surfaces exhibited Level-I to level-II LFPs, with low background interference.

Polycyclic aromatic hydrocarbon: underpinning the contribution of specialist microbial species to contaminant mitigation in the soil

The persistence of PAHs poses a significant challenge for conventional remediation approaches, necessitating the exploration of alternative, sustainable strategies for their mitigation. This review underscores the vital role of specialized microbial species (nitrogen-fixing, phosphate-solubilizing, and biosurfactant-producing bacteria) in tackling the environmental impact of polycyclic aromatic hydrocarbons (PAHs). These resistant compounds demand innovative remediation strategies. The study explores microbial metabolic capabilities for converting complex PAHs into less harmful byproducts, ensuring sustainable mitigation. Synthesizing literature from 2016 to 2023, it covers PAH characteristics, sources, and associated risks. Degradation mechanisms by bacteria and fungi, key species, and enzymatic processes are examined. Nitrogen-fixing and phosphate-solubilizing bacteria contributions in symbiotic relationships with plants are highlighted. Biosurfactant-producing bacteria enhance PAH solubility, expanding microbial accessibility for degradation. Cutting-edge trends in omics technologies, synthetic biology, genetic engineering, and nano-remediation offer promising avenues. Recommendations emphasize genetic regulation, field-scale studies, sustainability assessments, interdisciplinary collaboration, and knowledge dissemination. These insights pave the way for innovative, sustainable PAH-contaminated environment restoration.

UHPM dominance in driving the formation of petroleum-contaminated soil aggregate, the bacterial communities succession, and phytoremediation

This study focused on the effects of urea humate-based porous materials (UHPM) on soil aggregates, plant physiological characteristics, and microbial diversity to explore the effects of UHPM on the phytoremediation of petroleum-contaminated soil. The compositions of soil aggregates, ryegrass (Lolium perenne) biomass, plant petroleum enrichment capacity, and bacterial communities in soils with and without UHPM were investigated. The results showed that UHPM significantly increased soil aggregate content by 0.25 mm-5 mm, resulting in higher fertilizer holding capacity, erosion resistance capacity, and plant biomass and microbial number than the soil without UHPM mixed. In addition, UHPM decreased the absorption of petroleum by plants in the soil while increasing the abundance of degrading bacteria and petroleum-degrading-related genes in the soil, thereby promoting the removal of hard-to-degrade petroleum components. RDA showed that, compared with the unimproved soil, each soil indicator was positively correlated with a high abundance of degrading bacteria in the improved soil and was significant. UHPM can be regarded as a petroleum-contaminated soil remediation agent that combines slow nutrient release with soil improvement effects.

The effect of bioturbation on the release behavior of polycyclic aromatic hydrocarbons from sediments: A sediment-seawater microcosm experiment combined with a fugacity model

The effects of two benthonic species, Perinereis aibuhitensis and Matuta planipes Fabricius, on the release of polycyclic aromatic hydrocarbons (PAHs) from sediments were investigated using a sediment-seawater microcosm. A Level IV fugacity model was used to simulate the behavior and fate of PAHs in the environment. This study revealed that both benthos significantly influenced the release of PAHs, and Matuta planipes Fabricius had a stronger disturbance effect than another. The final concentrations of Matuta planipes Fabricius group, Perinereis aibuhitensis group and the control group in the seawater phase reached 10.8, 9.94 and 7.90 μg/L, respectively. There were certain differences in the behaviour of the two benthonic species. Matuta planipes Fabricius caused more sediment resuspension, while Perinereis aibuhitensis increased the total organic carbon (TOC) content in the environment. The vertical concentration distribution of sediment indicated that vertical mixing was slightly stronger in the Matuta planipes Fabricius group than that in the Perinereis aibuhitensis group. The fugacity model effectively simulated the release behavior of PAHs, providing insight into PAH transport and distribution. The results demonstrated that bioturbation could promote the release of PAHs from seawater. The amount of PAHs released was significantly correlated with the biological habits of the benthos.

Predicting thermal desorption efficiency of PAHs in contaminated sites based on an optimized machine learning approach

Thermal desorption (TD) remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated sites is known for its high energy consumption and cost implications. The key to solving this issue lies in analyzing the PAHs desorption process, defining remediation endpoints, and developing prediction models to prevent excessive remediation. Establishing an accurate prediction model for remediation efficiency, which involves a systematic consideration of soil properties, TD parameters, and PAH characteristics, poses a significant challenge. This study employed a machine learning approach for predicting the remediation efficiency based on batch experiment results. The results revealed that the extreme gradient boosting (XGB) model yielded the most accurate predictions (R2 = 0.9832). The importance of features in the prediction process was quantified. A model optimization scheme was proposed, which involved integrating features based on their relevance, importance, and partial dependence. This integration not only reduced the number of input features but also enhanced prediction accuracy (R2 = 0.9867) without eliminating any features. The optimized XGB model was validated using soils from sites, demonstrating a prediction error of less than 30%. The optimized XGB model aids in identifying the most optimal conditions for thermal desorption to maximize the remediation efficiency of PAH-contaminated sites under relative cost and energy-saving conditions.

Carbon-based adsorbents for the mitigation of polycyclic aromatic hydrocarbon: a review of recent research

Accumulation of polycyclic aromatic hydrocarbons (PAH) poses significant dangers to the environment and human health. The advancement of technology for cleaning up PAH-contaminated environments is receiving more attention. Adsorption is the preferred and most favorable approach for cleaning up sediments polluted with PAH. Due to their affordability and environmental friendliness, carbonaceous adsorbents (CAs) have been regarded as promising for adsorbing PAH. However, adsorbent qualities, environmental features, and factors may all significantly impact how well CAs remove PAH. According to growing data, CAs, most of which come from laboratory tests, may be utilized to decontaminate PAH in aquatic setups. However, their full potential has not yet been established, especially concerning field applications. This review aims to concisely summarize recent developments in CA, PAH stabilization processes, and essential field application-controlling variables. This review analysis emphasizes activated carbon, biochar, Graphene, carbon nanotubes, and carbon-nanomaterials composite since these CAs are most often utilized as adsorbents for PAH in aquatic systems.

Environmental impact and human health effects of polycyclic aromatic hydrocarbons and remedial strategies: A detailed review

Polycyclic Aromatic Hydrocarbons (PAHs) profoundly impact public and environmental health. Gaining a comprehensive understanding of their intricate functions, exposure pathways, and potential health implications is imperative to implement remedial strategies and legislation effectively. This review seeks to explore PAH mobility, direct exposure pathways, and cutting-edge bioremediation technologies essential for combating the pervasive contamination of environments by PAHs, thereby expanding our foundational knowledge. PAHs, characterised by their toxicity and possession of two or more aromatic rings, exhibit diverse configurations. Their lipophilicity and remarkable persistence contribute to their widespread prevalence as hazardous environmental contaminants and byproducts. Primary sources of PAHs include contaminated food, water, and soil, which enter the human body through inhalation, ingestion, and dermal exposure. While short-term consequences encompass eye irritation, nausea, and vomiting, long-term exposure poses risks of kidney and liver damage, difficulty breathing, and asthma-like symptoms. Notably, cities with elevated PAH levels may witness exacerbation of bronchial asthma and chronic obstructive pulmonary disease (COPD). Bioremediation techniques utilising microorganisms emerge as a promising avenue to mitigate PAH-related health risks by facilitating the breakdown of these compounds in polluted environments. Furthermore, this review delves into the global concern of antimicrobial resistance associated with PAHs, highlighting its implications. The environmental effects and applications of genetically altered microbes in addressing this challenge warrant further exploration, emphasising the dynamic nature of ongoing research in this field.

Facile construction of magnetic solid-phase extraction of polyaniline blend poly(amidoamine) dendrimers modified graphene oxide quantum dots for efficient adsorption of polycyclic aromatic hydrocarbons in environmental water

An efficient magneto-adsorbent composed of polyaniline blend poly(amidoamine) dendrimers modified graphene oxide quantum dots and magnetic Fe3O4 particles (Fe3O4@PANI-PSS/PAMAM-QGO) for magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in environmental water was synthesized. Fe3O4@PANI-PSS/PAMAM-QGO exhibited exceptional adsorption property for most PAHs analytes. The nanocomposite sorbent demonstrated a ferromagnetic behavior of 17.457 emu g-1, which is adequate for subsequent use in MSPE. Key parameters affecting the processes of adsorption and desorption, including the sorbent amount, vortex adsorption time, vortex extraction time, sample volume, a solvent for desorption and the solvent volume were all examined and optimized. The performance of MSPE using Fe3O4@PANI-PSS/PAMAM-QGO as adsorbent for four PAHs, including fluoranthene, acenaphthene, phenanthrene and pyrene were studied through high performance liquid chromatography equipped with spectrofluorometer. Under the optimal conditions, Fe3O4@PANI-PSS/PAMAM-QGO showed a wide linearity of 10-1,000 ng mL-1, low detection limit (LOD) ranging from 1.92 to 4.25 ng mL -1 and high accuracy (recoveries of 93.6-96.5 %). Enrichment factors up to 185 were achieved. Furthermore, Fe3O4@PANI-PSS/PAMAM-QGO exhibited good recyclability (10 times, RSDs ≤ 5.35%), while maintaining its high efficiency in the extraction of PAHs. The proposed method was successfully applied for environmental samples. Recoveries ranging from 81.2 to 106.2 % were obtained, indicating a low matrix effect and the robustness of the optimized MSPE method. Based on these features and under the optimal extraction conditions, Fe3O4@PANI-PSS/PAMAM-QGO was demonstrated to be a successful tool for the rapid and sensitive extraction of PAHs in the samples.

Microbes and microbial strategies in carcinogenic polycyclic aromatic hydrocarbons remediation: a systematic review

Degradation, detoxification, or removal of the omnipresent polycyclic aromatic hydrocarbons (PAHs) from the ecosphere as well as their prevention from entering into food chain has never appeared simple. In this context, cost-effective, eco-friendly, and sustainable solutions like microbe-mediated strategies have been adopted worldwide. With this connection, measures have been taken by multifarious modes of microbial remedial strategies, i.e., enzymatic degradation, biofilm and biosurfactant production, application of biochar-immobilized microbes, lactic acid bacteria, rhizospheric-phyllospheric-endophytic microorganisms, genetically engineered microorganisms, and bioelectrochemical techniques like microbial fuel cell. In this review, a nine-way directional approach which is based on the microbial resources reported over the last couple of decades has been described. Fungi were found to be the most dominant taxa among the CPAH-degrading microbial community constituting 52.2%, while bacteria, algae, and yeasts occupied 37.4%, 9.1%, and 1.3%, respectively. In addition to these, category-wise CPAH degrading efficiencies of each microbial taxon, consortium-based applications, CPAH degradation-related molecular tools, and factors affecting CPAH degradation are the other important aspects of this review in light of their appropriate selection and application in the PAH-contaminated environment for better human-health management in order to achieve a sustainable ecosystem.

Microalgae mediated bioremediation of polycyclic aromatic hydrocarbons: Strategies, advancement and regulations

Polycyclic aromatic hydrocarbons (PAHs) are pervasive in the atmosphere and are one of the emerging pollutants that cause harmful effects in living systems. There are some natural and anthropogenic sources that can produce PAHs in an uncontrolled way. Several health hazards associated with PAHs like abnormality in the reproductive system, endocrine system as well as immune system have been explained. The mutagenic or carcinogenic effects of hydrocarbons in living systems including algae, vertebrates and invertebrates have been discussed. For controlling PAHs, biodegradation has been suggested as an effective and eco-friendly process. Microalgae-based biosorption and biodegradation resulted in the removal of toxic contaminants. Microalgae both in unialgal form and in consortium (with bacteria or fungi) performed good results in bioaccumulation and biodegradation. In the present review, we highlighted the general information about the PAHs, conventional versus advanced technology for removal. In addition microalgae based removal and toxicity is discussed. Furthermore this work provides an idea on modern scientific applications like genetic and metabolic engineering, nanomaterials-based technologies, artificial neural network (ANN), machine learning (ML) etc. As rapid and effective methods for bioremediation of PAHs. With several pros and cons, biological treatments using microalgae are found to be better for PAH removal than any other conventional technologies.

Carbon Dots from Tire Waste for the Photodegradation of Methyl Orange Dye, Antimicrobial Activity, and Molecular Docking Study

In this study, solvothermal pathway was employed for the synthesis of P, N codoped C-dot using tire waste as a sustainable source of carbon and nitrogen. Comprehensive analyses encompassing X-ray diffraction (XRD) analysis, Transmission Electron Microscopy (TEM), FT-IR, cyclic voltammetry, and UV-Vis spectra were used to assess the crystalline structure, purity, size, fluorescence up-conversion, and morphological attributes of the nanomaterial. Subsequently, the produced C-dots were evaluated for their efficacy in the photocatalytic degradation of methylene blue and methyl orange dyes, demonstrating notable success in degrading methyl orange dye within eight hours in the visible region. Furthermore, the same nanomaterial was applied for carrying out agar disk-diffusion assays against a spectrum of microorganisms. Results revealed substantial inhibition zones against Methicillin-Resistant Staphylococcus aureus (MRSA), Escherichia coli, and Pseudomonas aeruginosa. Elucidating the antimicrobial mechanism, molecular-docking simulations were excuted using on AutoDock Vina with designated ligands. The results indicated a strong binding affinity of the C-dots with certain proteins associated with antibacterial activity. This observation suggests that the synthesized C-dots effectively engage with the active sites of these proteins, indicating their potential as promising antibacterial agents. Importantly, this study implies that C-dots do not induce protein denaturation, thereby warranting further investigation of their utility as antibacterial agents.

Microbiome based approaches for the degradation of polycyclic aromatic hydrocarbons (PAHs): A current perception

Globally, polycyclic aromatic hydrocarbons (PAHs) pollution is primarily driven by their release into the air through various combustion processes, including burning fossil fuels such as coal, oil, and gas in motor vehicles, power plants, and industries, as well as burning organic matter like wood, tobacco, and food in fireplaces, cigarettes, and grills. Apart from anthropogenic pollution sources, PAHs also occur naturally in crude oil, and their potential release during oil extraction, refining processes, and combustion further contributes to contamination and pollution concerns. PAHs are resistant and persistent in the environment because of their inherent features, viz., heterocyclic aromatic ring configurations, hydrophobicity, and thermostability. A wide range of microorganisms have been found to be effective degraders of these recalcitrant contaminants. The presence of hydrocarbons as a result of numerous anthropogenic activities is one of the primary environmental concerns. PAHs are found in soil, water, and the air, making them ubiquitous in nature. The presence of PAHs in the environment creates a problem, as their presence has a detrimental effect on humans and animals. For a variety of life forms, PAH pollutants are reported to be toxic, carcinogenic, mutation-inducing, teratogenic, and immune toxicogenics. Degradation of PAHs via biological activity is an extensively used approach in which diverse microorganisms (fungal, algal, clitellate, and protozoan) and plant species and their derived composites are utilized as biocatalysts and biosurfactants. Some microbes have the ability to transform and degrade these PAHs, allowing them to be removed from the environment. The goal of this review is to provide a critical overview of the existing understanding of PAH biodegradation. It also examines current advances in diverse methodologies for PAH degradation in order to shed light on fundamental challenges and future potential.