Biodegradation最新文献

Sanitary landfilling remains a cost-effective waste management strategy, employing engineered liners and leachate collection systems to mitigate environmental pollution. However, long-term degradation of compacted clay baseliners (CCLs) poses risks to environmental safety and groundwater quality. This study investigated seasonal and habitat-specific microbial communities within CCLs and leachate from the Pulau Burung Sanitary Landfill, Pinang, Malaysia, utilizing 16S rRNA gene amplicon sequencing and functional prediction via PICRUSt2. Triplicate samples were collected from leachate and baseliner layers (0–30 cm depth) during both rainy and dry seasons, alongside assessments of physicochemical properties and permeability. Significant seasonal differences (p < 0.05) were observed in the physicochemical profiles of leachate and baseliner samples. Baseliner microbiomes exhibited greater compositional stability and smaller beta-diversity shifts compared to the more dynamic leachate communities. Alpha diversity increased in both matrices during the dry season, although changes in baseliner richness were not statistically significant (p > 0.05). Microbial community shifts were primarily driven by seasonal variations in environmental parameters. Core phyla shared across both habitats included Pseudomonadota (31.15–45.88%), Bacillota (8.58–31.15%), Actinobacteriota (6.22–19.58%), Acidobacteriota (0.16–15.85%), Chloroflexota (0.85–13.84%), and Bacteroidota (1.38–12.74%). Additional phyla such as Patescibacteria (0.77–2.06%), Cyanobacteria (0.12–6.16%), Desulfobacterota (0.77–5.38%), and Verrucomicrobiota (0.59–2.33%) showed matrix-specific enrichment. Functional prediction revealed distinct enzyme profiles and metabolic pathway enrichment. Anaerobic genera such as Geobacter, Desulfuromonas, Desulfuromusa, Pseudopelobacter, Desulfotomaculum, Clostridium, Desulfitobacterium, Telmatospirillum, and Dethiobacter were associated with redox cycling and mineral-transforming processes, suggesting potential contributions to increased clay porosity and reduced structural integrity. These findings demonstrate the ecological and functional complexity of landfill microbiomes and their potential role in compromising barrier performance. The study recommends routine monitoring of microbial functional genes and the development of biogeochemically resilient clay blends or in situ biobarriers to enhance long-term containment efficacy.

This study investigates the biodegradation of polymer polyethylene terephthalate (PET) by Enterobacter hormaechei, which was isolated from the Chennai coastal region, India. The degradation was characterized using Fourier transform infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD), Raman spectroscopy, Particle Size analyzer, and Field emission scanning electron microscopy (FESEM) coupled with EDX. FT-IR revealed the formation of C–O (ether group) and the C–H (methylene group) bonds. Raman spectroscopy confirmed the emergence of a new formation group at the 1216 cm⁻¹ Raman shift. XRD analysis revealed reduced crystallinity and structural alterations in PET, indicating bacterial–mediated modification of the polymer structure. FESEM analysis revealed significant morphological changes, accompanied by a 60.0% reduction in carbon content, corresponding to 65.5% PET degradation. In conclusion, Enterobacter hormaechei can efficiently utilise PET as a carbon source and highlighting its potential in polymer degradation.

With the decline of freshwater resources, attention is increasingly directed towards recovering, reusing, and recycling water. In addition, stringent compliance mandates for wastewater disposal, increasing treatment expenses, and spatial limitations necessitate an alternative solution. Due to its wide applicability, membrane technology has received significant attention in conjunction with biological treatment methods. Numerous studies have demonstrated satisfactory performance attributes of membrane systems over a few decades. This paper presents a comprehensive review of MBR operation, delving into the configurations, design attributes, membrane fouling, and strategies for its control. Furthermore, the possibilities and implementation of MBR as a viable solution for wastewater treatment have been examined. The data regarding process parameters and effluent quality are presented to assess the key findings of the aerobic membrane bioreactor (AeMBR). Essential elements like loading rates, retention time, cross-flow velocities, types of membranes, membrane fouling, and backwashing are also reviewed. This study delves deeper into contemporary mathematical models and simulations aimed at forecasting MBR efficiency. The focus is on employing membranes as solid/liquid separators, which are essential for attaining directly reusable effluent quality. The review also accounts for a financial analysis, for the selection of a process based on economic feasibility.

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Phages are a major cause of bacterial mortality, affecting bacterial diversity and ecosystem functioning. However, the impact of phage-host interactions in contaminated environments and their role in pollutant biodegradation have largely been overlooked. We isolated and characterized a novel phage that infects the PAH-degrading bacterium Paraburkholderia caledonica Bk from a polycyclic aromatic hydrocarbon (PAH)-contaminated soil and investigated the effect of different multiplicity of infection (MOI) ratios on the degradation efficiency of phenanthrene. The phage IPK is a temperate phage with a wide pH and temperature tolerance and a burst size of 80  PFU ml⁻¹. The phage was classified as a member of the Caudoviricetes and is related to Pseudomonas and Burkholderia phages. However, its low intergenomic similarity indicates that it is a new species. Three auxiliary metabolic genes (AMGs) related to amino acid metabolism and to bacterial growth regulation were identified in the phage genome. The highest multiplicity of infection (MOI 10) showed a rapid recovery of the host density and greater phenanthrene degradation than MOIs ranging from 0.01 to 1. This work highlights the important role of phage-host interactions in modulating the efficiency of pollutant degradation, which could be a key for improving the establishment of inoculants in bioremediation processes.

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Mealworm larvae (Tenebrio molitor) have emerged as a promising biological agent for degrading synthetic plastics. This study aimed to establish a non-invasive method to monitor plastic biodegradation by linking oxygen consumption to metabolic activity and to investigate microbial and chemical changes associated with plastic degradation. Larvae were maintained under controlled conditions (25 ± 0.5 °C; 75 ± 5% relative humidity) and fed expanded polystyrene (EPS) or polypropylene (PP) for 28 days. Survival rates, daily plastic consumption, and oxygen uptake were recorded. Frass was analyzed for molecular weight changes, while GC–MS, FTIR, and NMR were used to detect chemical modifications in degraded polymers. Gut microbiota composition was assessed by sequencing to identify taxa associated with plastic diets. Survival exceeded 80% in plastic-fed groups compared to 44.2% in unfed controls. Mean daily plastic consumption per 100 larvae was 15.7 ± 2.2 mg (EPS) and 16.4 ± 1.5 mg (PP). Frass analysis revealed significant depolymerization, while GC–MS, FTIR, and NMR confirmed oxidative modifications and the formation of shorter-chain alkanes. Microbiome profiling showed consistent presence of Spiroplasma, Lactococcus, and Enterococcus, with enrichment of Staphylococcus and Providencia in EPS-fed groups. Oxygen uptake correlated with plastic degradation, validating it as a real-time metabolic indicator. This study demonstrates that oxygen uptake can serve as a real-time proxy for plastic degradation in vivo, providing higher temporal resolution than endpoint assays. The findings highlight the dual role of larvae and their gut microbiome in polymer breakdown, offering new insights into sustainable bioconversion strategies for plastic waste.

Coal mining and coal combustion for energy generation will continue in the medium term and remain a primary source of pollutants. Its complex structure renders coal a recalcitrant material and relatively few bacteria and fungi can thus degrade this carbonaceous substrate. In this review, we assess research progress on the biological degradation and solubilisation of coal, waste coal, discard and gangue from 2014 to 2024, the period following the publication of our 2013 critical appraisal of this topic. We focus on the continued need for studies on coal biodegradation and bio-solubilization. We explore and, where appropriate, evaluate some of the more important recent advances in coal bio-solubilization research to illustrate progress in this field. Of particular significance are the ever-increasing number of bacterial and fungal biocatalysts identified as possessing coal degrading potential, the role of microbial consortia in this process, the aerobic and anaerobic mechanisms of coal utilisation, and progress in elucidating the underlying molecular and biochemical events involved. Also reviewed are advances in the application of industrial products derived from coal, including biomethane, coal-bed methane, and humic substances, and the use of waste and discard coal-derived humics as technosols for soil restoration and the commercial-scale rehabilitation of coal mining-affected land. It is concluded that an understanding of the mechanisms underpinning coal biodegradation is critical in combating many of the detrimental impacts of mined coal, exposed coal seams and stockpiled coal mine waste and that the outputs from these studies must be incorporated into the development of diversified production technologies and strategies for both socio-economic and ecological gain.

The increasing occurrence of pharmaceutical compounds in aquatic environments poses significant ecological and public health challenges due to the persistence and bioaccumulation potential. While Aspergillus flavus and Cunninghamella elegans have demonstrated efficacy in removing heavy metals and dyes, their potential for pharmaceutical bioremediation remains unexplored. This study investigated these fungi capacity to degrade three persistent fluorinated pharmaceutical–atorvastatin (ATO), ciprofloxacin (CIP), and fluoxetine (FLX), through an innovative biofilm-based approach. Using polyurethane foam (PUF) as a carrier in two different configurations (fixed foam (PUF-F) and moving foam (PUF-M)), the performance of both fungal species was evaluated. C. elegans biofilms on PUF-F demonstrated high removal efficiencies of 97.3% for ATO and 97.7% for CIP, while A. flavus achieved 92.4% FLX reduction in the same system. Notably, the biofilm-based systems consistently outperformed carrier-free cultures, confirming the advantage of immobilized fungal growth. Kinetic analysis indicated pseudo-first-order degradation with remarkably short half-lives (1.0–1.7 days), surpassing reported values for white-rot fungi. Although adsorption contributed minimally (< 10%) to overall removal, species-specific biofilm characteristics emerged as key factors: C. elegans exhibited superior surface hydrophobicity (0.76) and stress resistance, whereas A. flavus developed denser extracellular matrices. These findings highlight the potential of tailored fungal biofilm systems for efficient removal of recalcitrant pharmaceutical, presenting a promising biological solution for wastewater treatment applications. The study provides critical insights into species-specific degradation mechanisms and operational parameters that could guide the development of scalable fungal bioremediation technologies.

1,2,3-Trichloropropane (1,2,3-TCP) is a suspected human carcinogen and a persistent emerging contaminant in groundwater and drinking water. 1,2,3-TCP was historically used as a solvent for cleaning and maintenance, paint and varnish removal, and degreasing, but its sources also include chemical manufacturing processes and application of soil fumigants. The California Department of Public Health (CDPH) has established a state maximum contaminant level (MCL) of 0.005 µg/L for 1,2,3-TCP in drinking water and a public health goal (PHG) of only 0.0007 µg/L. The primary research question addressed herein was whether aerobic or anaerobic cultures can potentially be applied for treatment of 1,2,3-TCP, and whether bacteria are capable of biodegrading 1,2,3-TCP to below the California MCL. During this study, we identified cultures capable of biodegrading 1,2,3-TCP via reductive dehalogenation as well as through aerobic cometabolic processes. Follow-on studies with organisms capable of aerobically degrading 1,2,3-TCP included kinetic modeling and assessment of concentrations of 1,2,3-TCP achievable via biodegradation. 1,2-Dichloropropane (1,2-DCP) is sometimes found co-mingled with 1,2,3-TCP, so studies also were conducted to quantify rates of 1,2-DCP biodegradation alone and when present together with 1,2,3-TCP. The dehalogenating consortium CPD-2, which was isolated from sewage sludge and includes Dehalococcoides, Dehalobacter and Dehalobium spp., biodegraded both 1,2,3-TCP and 1,2-DCP. Anaerobic 1,2,3-TCP degradation resulted in a transient production of 1,2-DCP followed by 1-chloropropane (1-CP), which accumulated nearly stoichiometrically and then slowly degraded, indicating complete dechlorination of 1,2,3-TCP by this mixed culture. Two different cometabolic pure cultures, Rhodococcus ruber ENV425 and Rhodococcus aetherivorans ENV493 degraded 1,2,3-TCP after growth on propane or isobutane. Importantly, both bacteria were capable of degrading 20 µg/L of 1,2,3-TCP to < 0.005 µg/L after growth on isobutane. Experiments conducted with ENV425 and ENV493 to quantify relevant kinetic parameters after growth on isobutane suggested that ENV425 facilitated more rapid 1,2,3-TCP degradation than ENV493. Both strains were observed to degrade 1,2-DCP much faster than 1,2,3-TCP when present individually or in mixtures. The data from this study suggest that cometabolic treatment of 1,2,3-TCP, or mixtures of 1,2-DCP and 1,2,3-TCP, is feasible and that relevant regulatory concentrations are achievable using this process. Similarly, anaerobic treatment may be possible at locations with higher concentrations or where 1,2,3-TCP occurs with other chlorinated solvents.

The current research explores the microbial synthesis of manganese oxide nanoparticles from Stenotrophomonas sp. their characterization, and subsequent application against the degradation of fluorene hydrocarbon. There are several physical and chemical strategies to treat polycyclic aromatic hydrocarbons. But Nano-bioremediation is most effective and economical in degrading the polycyclic aromatic hydrocarbons. Various structural, crystalline, and optical characteristics of manganese oxide nanoparticles were investigated. Manganese oxide nanoparticle formation is indicated by a distinctive peak at 248 nm with a 3.5 eV band gap. X-ray diffraction demonstrated that manganese oxide nanoparticles had a crystalline grain size of 6.3 nm. Scanning and high-resolution transmission electron micrographs reveal the agglomerated spherical form. Manganese and oxygen existence and purity were validated with EDAX analysis. This study investigated the optimizational degradation of fluorene hydrocarbon using response surface methodology. The degradation of fluorene hydrocarbon was examined using Fourier Transform Infrared Spectroscopy and Gas chromatography–mass spectrometric analysis. Trigonella foenum-graecum was used in the phyto-toxicity study of fluorene degradation by microbial-synthesized manganese oxide nanoparticles.

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Current humic substances (HSs) production for bioremediation suffers from low yields and inconsistent functionality. The present work examined humic acid (HA) and fulvic acid (FA) extraction from compost treated with (1) molasses alone (CK), (2) Pseudomonas aeruginosa (T1), (3) Bacillus firmus (T2), and (4) a synergistic combination of molasses and both microbes (T3). The humic substances (HSs) were extracted using the standard alkaline extraction followed by the acid precipitation method. HSs were characterized over a period of 75 days using inductively coupled plasma mass spectrometry (ICP-MS) for heavy metals, Fourier-transform infrared spectrophotometer (FTIR), UV–Vis spectrophotometer, and X-ray photoelectron spectroscopy (XPS) for functional groups, along with elemental analysis. Results demonstrated that T3 significantly enhanced HA yield (4.76 g/kg) with optimal C/N (1.06) and E4/E6 (4.33) ratios, while T1 yielded the highest FA (2.18 g/kg) by day 60. In the HA fraction, T3 significantly reduced HM concentrations of Cd by 73%, Zn by 68%, and Fe by 45% in HA fractions, while revealing Cu and Mn bioavailability, providing a novel insight for targeted remediation indicating enhanced stabilization. Functional group engineering was validated by XPS, which indicated that T3 is uniquely enriched with redox-active groups, specifically carbonyl (C = O, 531.99 eV) and hydroxyl (C–OH, 532.96 eV). These groups facilitate the binding of nitrogen/sulfur species (amide: 400.24 eV; thiol: 163.45 eV), thereby enhancing bioremediation processes. Elemental analysis revealed enriched carbon (HA: 55.04%; FA: 56.24%) and oxygen (HA: 31.87%; FA: 31.73%), alongside elevated nitrogen, sulfur, and hydrogen. The T3 synergy demonstrates immediate applicability in the rehabilitation of contaminated soil.