Biodegradation最新文献

Phenoxyalkanoic acid herbicides are widely used in agricultural lands to kill the weeds in crop fields and have a very detrimental effect on soil’s natural fertility and its microbiome. Bacterial culture isolated from these lands in the presence of herbicides group 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2-Methyl-4-chlorophenoxy acetic acid (MCPA) belongs to plant growth hormone auxin. Strain LKDC4 Pseudomonas aeruginosa exposed to both herbicides at a range of concentrations 300 mg/L, 500 mg/L and 700 mg/L for 5 days without any enrichment culture, providing 2,4-D and MCPA as a carbon source for survival. LKDC4 shows a maximum number of cell growth in 2,4-D herbicide at the lowest concentration 300 mg/L (1.35 mM) comparatively with the highest concentration 700 mg/L (3.16 mM) of optical density 0.85 and 0.78 at 600 nm, respectively. At the same time, this strain shows a similar number of cell growth at all three concentrations 300 mg/L, 500 mg/L, and 700 mg/L of 1.49 mM, 2.49 mM, and 3.48 mM respectively of optical density 0.90 at 600 nm. The degradation efficiency of the Pseudomonas aeruginosa LKDC4 was 70 to 80% of 2,4-D herbicide when the growth medium contained 0.2% glucose as the only carbon source after 5 days at optimum conditions. The degradation of MCPA was 100% at 300 mg/L and 700 mg/L, while 81% degradation at 500 mg/L after 5 days of incubation at optimum conditions. P. aeruginosa can degrade both herbicides and survive well in their presence, making it a tolerant microbial strain.

Polyethylene terephthalate (PET) is a huge part of consumer products such as beverage bottles, packaging materials, and textile fibres. It contributes significantly to persistent plastic pollution in freshwater ecosystems. This study explores the biodeterioration potential of seven indigenous freshwater microalgae isolated from water bodies near Indore, India, for sustainable PET degradation without chemical pre-treatment. Algal strains were incubated with PET granules for 20 days under controlled laboratory conditions (pH-7.2, temp. 27 ± 3 °C, light intensity of 40.5 µmol/m²/s, and a 12:12 h light–dark period). The average specific growth rate (μ) of the microalgal strains was 0.07 ± 0.01 μ/day. Among these, Asterarcys quadricellulare exhibited the highest deterioration efficiency, achieving a weight loss of 10%, followed by Scenedesmus sp. with a weight loss of 6%. Scanning electron microscopy (SEM), ATR-FTIR spectroscopy, and X-ray diffraction (XRD) analysis revealed notable cracks, chemical alterations, and reduction in crystallinity, respectively. Transmittance intensity of the characteristics FTIR spectra at 1715 cm⁻¹ demonstrated a sharp increase, indicating the formation of carbonyl groups. The reduction in the crystallinity of PET granules was consistently demonstrated by both FTIR and XRD analyses, confirming structural deformities induced by the algal strains. Biochemical analysis revealed that strains A. quadricellulare, C. proboscideum, and P. daitoensis exhibited a significant increase in lipid, protein, and carbohydrate concentration compared to the control. This study highlights the efficacy of unicellular microalgal strains in mitigating PET pollution in aquatic systems while enabling biomass valorisation for other sustainable applications.

The escalating global production and usage of paracetamol (C₈H₉NO₂), a widely administered analgesic and antipyretic pharmaceutical, has led to its ubiquitous presence in environmental matrices, including surface waters, municipal wastewater, and even potable water sources. Owing to its persistence and bioaccumulative potential, paracetamol poses a significant ecotoxicological threat, particularly through trophic transfer in aquatic ecosystems. Conventional wastewater treatment methods often fall short in completely eliminating such micropollutants. In this context, bioremediation offers a promising, sustainable, and cost-effective alternative for pharmaceutical remediation. This study investigates the anaerobic degradation potential of two sulfate-reducing bacterial consortia, designated Consortium I and Consortium II, isolated from Okhla landfill leachate and enriched with distinct Postgate media formulations. Paracetamol was introduced at varying concentrations (50–500 mg/L), with and without supplementation of an auxiliary carbon source, sodium lactate. Metagenomic profiling via 16S rRNA sequencing revealed that Consortium I was primarily composed of Clostridium (40.1%) and Acidipropionibacterium (31.2%), whereas Consortium II exhibited a dominant presence of Clostridium (80.3%) and Bacillus (7.99%). Consortium II exhibited superior degradation kinetics, achieving complete removal of 500 mg/L paracetamol in 48 h under lactate-free conditions. Conversely, the presence of sodium lactate significantly attenuated degradation efficiency, suggesting substrate competition and metabolic preference. Gas chromatography-mass spectrometry (GC-MS) identified 4-aminophenol and hydroquinone as transient intermediates, supporting a proposed anaerobic degradation pathway for paracetamol. These findings underscore the potential of native sulfate reducing bacterial consortia in the bioremediation of contaminants and provide mechanistic insight into anaerobic paracetamol degradation, offering a viable strategy for enhanced treatment efficacy of contaminated waste streams.

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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.