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Bioaugmentation effectively enhances microbial bioremediation of hazardous polycyclic aromatic hydrocarbons (PAHs) from contaminated environments. While screening for pyrene-degrading bacteria from a former manufactured gas plant soil (MGPS), the mixed enrichment culture was found to be more efficient in PAHs biodegradation than the culturable pure strains. Interestingly, analysis of 16S rRNA sequences revealed that the culture was dominated by a previously uncultured member of the family Rhizobiaceae. The culture utilized C1 and other methylotrophic substrates, including dimethylformamide (DMF), which was used as a solvent for supplementing the culture medium with PAHs. In the liquid medium, the culture rapidly degraded phenanthrene, pyrene, and the carcinogenic benzo(a)pyrene (BaP), when provided as the sole carbon source or with DMF as a co-substrate. The efficiency of the culture in the bioremediation of PAHs from the MGPS and a laboratory waste soil (LWS) was evaluated in bench-scale slurry systems. After 28 days, 80% of Σ16 PAHs were efficiently removed from the inoculated MGPS. Notably, the bioaugmentation achieved 90% removal of four-ringed and 60% of highly recalcitrant five- and six-ringed PAHs from the MGPS. Likewise, almost all phenanthrene, pyrene, and 65% BaP were removed from the bioaugmented LWS. This study highlights the application of the methylotrophic enrichment culture dominated by an uncultured bacterium for the efficient bioremediation of PAHs.

Pyrosequencing of 16S ribosomal RNA (rRNA) was employed to characterize bacterial communities colonizing the rhizosphere of plants with C3 and C4 photosynthetic pathways grown in soil contaminated with polycyclic aromatic hydrocarbons (PAHs) after 60 and 120 days. The results of this study exhibited a clear difference in bacterial diversity between the rhizosphere and non-rhizosphere samples and between the rhizospheres of the C3 and C4 plants after 120 days. In both C3 and C4 rhizospheres, an incremental change in PAHs degrading bacterial genera was observed in the 120th day samples compared to the 60th day ones. Among the PAHs degrading bacterial genera, Pseudomonas showed good resistance to PAHs in the 120th day rhizosphere of both C3 and C4 plants. Conversely, the genus Sphingomonas showed sensitivity to PAHs in the 120th day rhizosphere soils of C3 plants only. Also, a significant increase in the PAHs degrading genera was observed at 120th day in the C4 rhizosphere in comparison to the C3 rhizosphere, which was reflected in a reduced PAHs concentration measured in the soil remediated with C4 plants rather than C3 plants. These results suggest that the rhizoremediation of PAHs was primarily governed by the plant photosystems, which led to differences in root secretions that caused the variation in bacterial diversity seen in the rhizospheres. This study is the first report to demonstrate the greater effectiveness of C4 plants in enhancing the PAHs degrading bacterial community than C3 plants.

Solar‐driven photothermal water evaporation is considered an elegant and sustainable technology for freshwater production. The existing systems, however, often suffer from poor stability and biofouling issues, which severely hamper their prospects in practical applications. Conventionally, photothermal materials are deposited on the membrane supports via vacuum‐assisted filtration or dip‐coating methods. Nevertheless, the weak inherent material‐membrane interactions frequently lead to poor durability, and the photothermal material layer can be easily peeled off from the hosting substrates or partially dissolved when immersed in water. In the present article, the discovery of the incorporation of borophene into cellulose nanofibers (CNF), enabling excellent environmental stability with a high light‐to‐heat conversion efficiency of 91.5% and water evaporation rate of 1.45 kg m−2 h−1 under simulated sunlight is reported. It is also demonstrated that borophene papers can be employed as an excellent active photothermal material for eliminating almost 100% of both gram‐positive and gram‐negative bacteria within 20 min under three sun irradiations. The result opens a new direction for the design of borophene‐based papers with unique photothermal properties which can be used for the effective treatment of a wide range of wastewaters. A novel borophene‐embedded cellulose paper is fabricated by incorporating two‐dimensional borophene nanosheets inside the cellulose fiber structure. The borophene paper exhibits outstanding absorption properties, featuring excellent stability and mechanical properties for photothermal water evaporation and bacterial killing applications.

Pyroligneous acid (PA) is often used in agriculture as a plant growth and yield enhancer. However, the influence of PA application on soil microorganisms is not often studied. Therefore, in this study, we investigated the effect of PA (0.01–5% w/w in soil) on the microbial diversity in two different soils. At the end of eight weeks of incubation, soil microbial community dynamics were determined by Illumina-MiSeq sequencing of 16S rRNA gene amplicons. The microbial composition differed between the lower (0.01% and 0.1%) and the higher (1% and 5%) concentration in both PA spiked soils. The lower concentration of PA resulted in higher microbial diversity and dehydrogenase activity (DHA) compared to the un-spiked control and the soil spiked with high PA concentrations. Interestingly, PA-induced plant growth-promoting bacterial (PGPB) genera include Bradyrhizobium, Azospirillum, Pseudomonas, Mesorhizobium, Rhizobium, Herbaspiriluum, Acetobacter, Beijerinckia, and Nitrosomonas at lower concentrations. Additionally, the PICRUSt functional analysis revealed the predominance of metabolism as the functional module’s primary component in both soils spiked with 0.01% and 0.1% PA. Overall, the results elucidated that PA application in soil at lower concentrations promoted soil DHA and microbial enrichment, particularly the PGPB genera, and thus have great implications for improving soil health.

The global effects of MP (MP) pollution on the environment are concerning, and they are exacerbated by the multiple sources of pollution in aquatic environments such as urban runoff, waste mismanagement, industrial pollution, and so on. South pacific islands host a large diversity of aquatic flora and fauna and given its ecological significance it is necessary to identify the sources of MP pollution in the region. To date, very little attention has been given to identify whether effluents from wastewater treatment plants (WWTP) are acting as a significant source of MP in the South Pacific region and its countries. Therefore, the present study analyzed and compared the treatment methods and fate of MPs in the country’s two main WWTPs: 1) the Kinoya WWTP (simple secondary clarifier and trickling filter) and 2) Natabua WWTP (secondary pond treatment system). Sampling locations were based on the different treatment stages, and samples were collected from each stage of treatment before effluents were released into the ocean. Kinoya WWTP had an average of 3.45 ± 0.3 particles/L in the inlet stage and released an average of 0.3 ± 0.26 particles/L of MP through the outlet with 91% removal efficiency (RE) with an output equivalent of 4500 particles per day. The initial stage of treatment from the anaerobic pond outlet at Natabua had an average of 2.9 ± 1.05 particles/L, and the maturation outlet had an average of 0.53 ± 0.42 particles/L, a removal efficiency of 81% and thus an output equivalent of 4558 particles/L of MP. Polymer analysis under FTIR confirmed that cellophane or semi-synthetic cellulose and polypropylene were common polymers in the final effluent in Kinoya WWTP, and Natabua plant has cellophane or semi-synthetic cellulose, polypropylene and polyethylene were observed as common polymers. Although there are numerous study that have compared wastewater treatment processes, this is the first study in Fiji that investigates the efficiency of the two methods of water treatment process in the context of microplastic pollution and emphasizes the effectiveness of the treatment stages in determining the concentration of MP released into the ocean.

Growing wastewater treatment demands drive reliance on polymeric materials to facilitate the process, and traditional fossil-based polymers face limitations, prompting the exploration of sustainable alternatives. Biopolymers derived from renewable sources (chitosan, keratin, and cellulose) offer advantages like biodegradability and enhanced adsorption. This review provides an overview of the potential biopolymer-based composites for removing various pollutants (pesticides, heavy metals, and dyes) and highlights the importance of reusing spent adsorbents for multiple applications.

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) under completely anaerobic sulfate-reducing conditions is an energetically challenging process. To date, anaerobic degradations of only two-ringed naphthalene and three-ringed phenanthrene by sediment-free and enriched sulfate-reducing bacteria have been reported. In this study, sulfate-reducing enrichment cultures capable of degrading naphthalene and four-ringed PAH, pyrene, were enriched from a contaminated former gas plant site soil. Bacterial community composition analysis revealed that a naphthalene-degrading enrichment culture, MMNap, was dominated (84.90%) by a Gram-positive endospore-forming member of the genus Desulfotomaculum with minor contribution (8.60%) from a member of Clostridium . The pyrene-degrading enrichment, MMPyr, was dominated (97.40%) by a species of Desulfotomaculum . The sequences representing the Desulfotomaculum phylotypes shared 98.80% similarity to each other. After 150 days of incubation, MMNap degraded 195 µM naphthalene with simultaneous reduction of sulfate and accumulation of sulfide. Similarly, MMPyr degraded 114 µM pyrene during 180 days of incubation with nearly stochiometric sulfate consumption and sulfide accumulation. In both cases, the addition of sulfate reduction inhibitor, molybdate (20 mM), resulted in complete cessation of the substrate utilization and sulfate reduction that clearly indicated the major role of the sulfate-reducing Desulfotomaculum in biodegradation of the two PAHs. This study is the first report on anaerobic pyrene degradation by a matrix-free, strictly anaerobic, and sulfate-reducing enrichment culture.

The phytoremediation technique has been demonstrated to be a viable option for the remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated sites. This study evaluated the potential applicability of plants with C3 and C4 carbon fixation pathways for the phytoremediation of recalcitrant high molecular weight (HMW) PAHs contaminated soil. A 60 and 120-day greenhouse study was conducted which showed higher degradation of HMW PAHs in soil grown with C4 plants when compared to C3 plants. Also, no PAHs were detected in the maize cobs, sunflower, wallaby, and Sudan grass seeds at the end of the experiment. The effect of plants in modifying the microbial community and dynamics in the rhizosphere was also examined by measuring soil biochemical properties such as dehydrogenase activity and water-soluble phenols. The results demonstrate a substantial difference in the microbial populations between planted and unplanted soils, which in turn facilitate the degradation of PAHs. To the best of our knowledge, this study for the first time evaluated the phytoremediation efficacy through the A. cepa cyto- and genotoxicity assay which should be considered as an integral part of all remediation experiments.

Microplastics (MPs) threaten biodiversity significantly, permeating aquatic and terrestrial ecosystems and disrupting essential biological and ecological processes. Insects, critical for maintaining ecosystem balance, are increasingly impacted by MP contamination. This review highlights the exposure routes of MP in insects that lead to physiological effects such as reduced reproductive success, altered behavior, and compromised immune responses. These disruptions may cause cascading effects on ecosystem services from insects such as pollination, natural pest control, and nutrient cycling, with profound consequences for agriculture and biodiversity. The review further explores strategies for mitigating MP pollution, including advancements in recycling technologies, improved monitoring methods, and the development of robust policy frameworks. The long-term ecological impacts of MP contamination on insect populations, including potential declines in key species and shifts in community dynamics, need to be focused on in future research. Developing bio-based solutions leveraging microbial and enzymatic approaches for MP degradation is also required. By integrating innovative research, education, and sustainable practices, a comprehensive response can be developed to mitigate the impacts of MPs on insects, protect biodiversity, and ensure ecosystem resilience in the face of growing environmental challenges. Article Highlights Microplastics (MPs) are an invisible threat to insect ecosystems. Insects encounter MPs via ingestion, inhalation, contact, and entanglement. MPs impact insect growth, reproduction, immunity, and gut microbiota. Ecosystem services like pollination, pest control, and nutrient cycling are affected. Mitigation strategies include recycling, monitoring, policies, and global cooperation. Graphical abstract

The insensitive munition ingredient, 2, 4-dinitroanisole has emerged as an alternative ingredient to 2, 4, 6-trinitro toluene in melt pourable high explosive formulations mainly due to its improved insensitiveness properties. As a result, production of 2, 4-dinitroanisole has increased and as a consequence 2, 4-dinitroanisole has emerged as a potential ingredient to enter the environment and possibly persist in water and soil ecosystems. The present study showed that 2, 4-dinitroanisole, its metabolites (2-amino 4-nitroanisole and 2,4-dinitroanisole) and 2, 4, 6-trinitro toluene were found to induce DNA damages in a freshwater crustacean Daphnia carinata exposed for 48 h and which was investigated by the alkaline single-cell gel electrophoresis (comet assay) method. The value of LC 50 —48 h of 2, 4-dinitroanisole was determined as 14.87 ± 1.70 (mg L −1 ) and its metabolites exhibited the similar toxic range although the toxicity of 2, 4, 6-trinitro toluene was seven-fold more toxic (2.32 ± 0.29 mg L −1 ) than 2, 4-dinitroanisole and its metabolites. Exposure to sub-acute toxicity concentration ranges of 2, 4-dinitroanisole and its metabolites and 2, 4, 6-trinitro toluene showed significant ( P  < 0.01) DNA damage. The higher concentration of each test chemical exhibited higher tail DNA per cent and increased olive tail moment. The results from this study can be used to identify genotoxic biomarkers for the risk assessment of insensitive munitions exposure in aquatic invertebrates.