Search Results (161)

This work investigated the use of microbial fuel cells (MFCs) for the degradation of polyethylene terephthalate (PET) and the simultaneous generation of electricity. The study implemented two separate single-chamber MFCs, one with a co-culture of Ideonella sakaiensis and Geobacter sulfurreducens (I.S-G.S) and the other with Ideonella sakaiensis and activated sludge (I.S-AS). The effectiveness of microplastic (MP) degradation was assessed based on the electroactivity of the anodic biofilm, the reduction in particle size, and the decrease in PET mass. Both systems achieved a significant reduction in MP size and mass, with the I.S-AS system notably surpassing the I.S-G.S in terms of efficiency and electricity generation. The I.S-AS system achieved a 30% mass reduction and 80% size reduction, along with a peak voltage of 222 mV. The study concludes that MFCs, particularly with the activated sludge co-culture, offer a viable and more environmentally friendly alternative for MP degradation and energy recovery. These findings suggest a promising direction for improving waste management practices and advancing the capabilities of bio-electrochemical systems in addressing plastic pollution. Further research is recommended to optimize the operational conditions and to test a broader range of MP sizes for enhanced degradation efficacy. Full article

As the environmental burden of traditional plastics continues to grow, bioplastics (BPs) have emerged as a promising alternative due to their renewable origins and potential for biodegradability. However, the most popular anaerobic systems (ASs)—anaerobic digestion (AD), acidogenic fermentation (AF), and enzyme hydrolysis (EH)—for BPs degradation still face many challenges, e.g., low degradation efficiency, process instability, etc. As a sustainable clean energy technology, bioelectrochemical systems (BESs) have demonstrated strong potential in the treatment of complex organic waste when integrated with ASs. Nevertheless, research on the synergistic degradation of BPs using BES-ASs remains relatively limited. This review systematically summarizes commonly used anaerobic degradation methods for BPs, along with their advantages and limitations, and highlights the BES-AS as an innovative strategy to enhance BPs degradation efficiency. BESs can accelerate the decomposition of complex polymer structures through the activity of electroactive microorganisms, while also offering benefits such as energy recovery and real-time process monitoring. When coupled with anaerobic digestion, the BES-AS demonstrates significant synergistic effects, improving degradation efficiency and promoting the production of high-value-added products such as volatile fatty acids (VFAs) and biogas, thereby showing great application potential. This review outlines current research progress, identifies key knowledge gaps in mechanism elucidation, system design, source recovery, etc., and proposes future research directions. These include system optimization, microbial community engineering, development of advanced electrode materials, and omics-based mechanistic studies. Advancing multidisciplinary integration is expected to accelerate the practical application of BES-ASs in BP waste management and contribute to achieving the goals of sustainability, efficiency, and circular utilization. Full article

Phthalic acid esters (PAEs) are important plasticizers that have led to the heavy pollution of farmland, which has aroused significant and widespread concern for soil health and food safety. Microbial degradation has been recognized as an efficient pathway for removing PAEs from the environment. In this study, the PAE-degrading strain FR1 was isolated from sewage and determined to belong to Glutamicibacter. This strain degraded PAEs efficiently under a wide range of conditions—10–50 °C, pH of 6.0–11.0, and 0–8% salinity—demonstrating its great potential in PAE bioremediation. Genome sequencing provided complete genomic information, showing that the strain comprises one chromosome (3,404,214 bp) and three plasmids (112,089 bp, 80,486 bp, and 40,002 bp). The chromosome harbors 3238 protein genes, of which the PAE hydrolase genes dphGB1 and mphGB2 have been cloned. The hydrolase DphGB1 from hydrolase family I contained the catalytic triad Ser75-Asp194-His221. After heterogeneous expression and purification, the recombinant protein DphGB1, of about 30 kDa, was obtained. This hydrolase showed strong hydrolytic ability toward DEHP. The protein MphGB2 could also hydrolyze MBP. The molecular docking revealed interaction between DphGB1 and DBP. The main hydrolases of strain FR1-degrading PAEs were functionally identified. These results will promote the elucidation of the catalytic mechanisms of PAE hydrolases and the application of strain FR1 in farmland soil remediation. Full article

The recurrent influx of invasive Sargassum horneri along the coasts of South Korea poses significant ecological and economic challenges, including habitat disruption, aquaculture damage, and shoreline pollution. This study investigates a sustainable valorization pathway by converting SH into functional biochar through slow pyrolysis and utilizing the product as a core material for eco-friendly marine buoys. Biochars were produced at pyrolysis temperatures ranging from 300 °C to 700 °C and characterized for elemental composition, FT-IR spectra, leachability (CODcr), and biodegradability. Higher pyrolysis temperatures resulted in lower H/C and O/C molar ratios, indicating enhanced aromaticity and hydrophobicity. The biochar produced at 700 °C (SFBW-700) exhibited the highest structural and environmental stability, with minimal leachability and resistance to microbial degradation. A composite buoy was fabricated by mixing SFBW-700 with natural binders (beeswax and rosin), forming solid specimens without synthetic polymers or foaming agents. The optimized composition (biochar:beeswax:rosin = 85:10:5) showed excellent performance in density, buoyancy, and impact resistance, while fully meeting the Korean eco-friendly buoy certification criteria. This work presents a circular and scalable approach to mitigating marine macroalgal blooms and replacing plastic-based marine infrastructure with biochar-based eco-friendly composite alternatives. The findings suggest strong potential for the deployment of SH-derived biochar in marine engineering applications. Full article

Plastics have been widely used in agriculture, particularly as mulching materials, due to their ability to improve soil conditions and enhance productivity. However, their degradation into microplastics (MPs) raises significant environmental and agronomic concerns, as these particles may change soil properties, affect microbial communities, and pose risks to surrounding ecosystems. While methodologies for MP detection in aquatic environments are well established, the analysis of MPs in soils remains challenging due to the complexity and heterogeneity of soil matrices. Currently, there is no standardized protocol for the determination of MPs in soils. This study critically evaluated and compared three different pre-treatment methods for removing organic matter from soil prior to MP analysis in an agricultural soil, and proposes a comprehensive methodology comprising two main phases: (i) organic matter removal, a crucial step of MP particles, and (ii) density separation of MP particles. Three distinct removal chemical methods were tested using samples from an agricultural soil in Southern Portugal. The most effective method was then applied to assess MP particles in an experimental field, using soil samples collected before mulching and 14 months later beneath a polyethylene-based soil cover. This was one of the first studies contributing to the establishment of a routine methodology for monitoring MPs in soils, particularly the agricultural soils, ensuring compliance with the future “Directive for Soil Monitoring”. Full article

Micro(nano)plastics are important emerging contaminants and a current research hotspot in the environmental field. Micro(nano)plastics widely exist in various organic wastes such as waste sludge, food waste (FW) and livestock manure and often enter into digesters along with anaerobic digestion (AD) treatment of these wastes, thereby exerting extensive and profound influences on anaerobic process performance. This study reviews sources of micro(nano)plastics and their pathways entering the anaerobic system and summarizes the quantities, sizes, shapes and micromorphology of various micro(nano)plastics in waste sludge, FW, livestock manure, yard waste and municipal solid waste. The current advances on the effects of multiple micro(nano)plastics mainly polyvinyl chloride (PVC), polystyrene (PS) and polyethylene (PE) with different sizes and quantities (or concentrations) on AD of organic wastes in terms of methane production, organic acid degradation and process stability are comprehensively overviewed and mechanisms of micro(nano)plastics affecting AD involved in microbial cells, key enzymes, microbial communities and antibiotic resistance genes are analyzed. Meanwhile, coupling effects of micro(nano)plastics with some typical pollutants such as antibiotics and heavy metals on AD are also reviewed. Due to the extreme complexity of the anaerobic system, current research still lacks full understanding concerning composite influences of different types, sizes and concentrations of micro(nano)plastics on AD under various operating modes. Future research should focus on elucidating mechanisms of micro(nano)plastics affecting organic metabolic pathways and the expression of specific functional genes of microorganisms, exploring the fate and transformation of micro(nano)plastics along waste streams including but not limited to AD, investigating the interaction between micro(nano)plastics and other emerging contaminants (such as perfluorooctanoic acid and perfluorooctane sulphonate) and their coupling effects on anaerobic systems, and developing accurate detection and quantification methods for micro(nano)plastics and technologies for eliminating the negative impacts of micro(nano)plastics on AD. Full article

Terephthalic acid (TPA), a major monomer of polyethylene terephthalate (PET), represents a significant challenge in plastic waste management due to its persistence in the environment. In this study, we report a newly developed bacterial consortium capable of using TPA as the sole carbon source in a defined mineral medium. The consortium achieved stationary phase within five days and metabolized approximately 85% of the available TPA. Metabolite analysis by high-performance liquid chromatography (HPLC) and liquid chromatography tandem mass spectrometry (LC-MS/MS) revealed the activation of the benzoate degradation pathway during TPA catabolism. Additionally, the consortium secreted commercially relevant metabolites such as cis,cis-muconic acid and catechol into the culture medium. Genetic profiling using a reverse transcription quantitative polymerase chain reaction (RT-qPCR) and 16S rRNA sequencing identified Paraburkholderia fungorum as the dominant species, suggesting it plays a key role in TPA degradation. The ability of this microbial community to efficiently convert TPA into high-value by-products offers a promising and potentially economically sustainable approach to addressing plastic pollution. Full article

Microplastic pollution has become a critical environmental issue, affecting terrestrial, freshwater, and marine ecosystems. These pollutants, originating from plastic degradation and primary sources, can act as carriers for harmful substances such as heavy metals and organic contaminants. While mitigation efforts are still in development, biological systems, particularly Black Soldier Fly Larvae (BSFL), have shown promise in organic waste management and pollutant bioaccumulation. Recent research explores the potential of BSFL to interact with and degrade microplastic particles, although the mechanisms remain underexplored. The role of microbial communities in facilitating microplastic degradation is of growing interest, as well as the impact of microplastic ingestion on the larvae’s efficiency in organic waste breakdown. However, experimental inconsistencies and environmental variations continue to delay progress, underscoring the need for further study to optimize bioremediation strategies and assess long-term ecological effects. This systematic review aims to explore the interactions between microplastics and BSFL, focusing on their potential as a bioremediation agent. It investigates the larvae’s ability to reduce microplastic pollution through bioaccumulation and degradation processes. Full article

Plastic pollution has emerged as a critical environmental challenge due to the widespread accumulation of petrochemical plastics in natural ecosystems. Conventional waste management strategies, including mechanical recycling and incineration, have demonstrated limited efficiency in addressing the persistence of plastics such as polyethylene, polypropylene, polyethylene terephthalate, and polyvinyl chloride. While incineration eliminates plastic material, it does not promote circularity and may generate toxic emissions. As a sustainable alternative, microbial biodegradation involves bacteria, fungi, and actinomycetes capable of degrading synthetic polymers through enzymatic processes. This review provides a comprehensive overview of microbial degradation of major plastics such as polyethylene, polypropylene, polyethylene terephthalate, and polyvinyl chloride, highlighting key strains, degradation rates, and enzymatic mechanisms. Importantly, biodegradation research also informs the development of in situ remediation technologies and supports new recycling strategies. Advances in protein engineering and synthetic biology are discussed for enhancing degradation efficiency. However, scaling biodegradation to environmental conditions remains challenging due to variable temperature, pH, microbial competition, and potentially toxic intermediates. Despite these limitations, microbial biodegradation represents a promising ecofriendly approach to address plastic waste and promote a biobased circular economy. Future work should integrate microbial processes into existing recycling infrastructure and design robust consortia guided by omics tools. Full article

The accumulation of plastic waste has intensified the pursuit of biodegradable alternatives, yet standard methods such as CO₂ evolution, oxygen demand, and mass loss fail to fully capture microbial physiological responses during degradation. This study introduces a biochemical assay-based approach to quantify proteins, lipids, and carbohydrates in soil as indicators of microbial activity during polymer biodegradation. For microcrystalline cellulose (MCC), proteins, lipids, and carbohydrates increased by 2.09-, 6.47-, and 11.22-fold, respectively (all p-values < 0.001), closely aligning with CO₂ evolution trends. Non-biodegradable poly(vinyl chloride) (PVC) exhibited no significant changes. Synthesized poly(butylene glutarate) (PBG) also showed significant biomolecule accumulation (up to 2.70-fold) alongside CO₂ production. Biomolecule quantification complements CO₂-based methods by revealing microbial proliferation and metabolic activity that persist beyond the mineralization plateau, offering a more comprehensive assessment of biodegradability. Full article

This study proposes a novel non-destructive approach to assessing and predicting the quality of stored date fruits using a composite quality index (Qi) modeled via visible–near-infrared (VIS–NIR) spectroscopy and artificial neural networks (ANNs). Two leading cultivars, Sukkary and Khlass, were stored for 12 months using three temperature regimes (25 °C, 5 °C, and −18 °C) and five types of packaging. The samples were grouped into six moisture content categories (4.36–36.70% d.b.), and key physicochemical traits, namely moisture, pH, hardness, total soluble solids (TSSs), density, color, and microbial load, were used to construct a normalized, dimensionless Qi. Spectral data (410–990 nm) were preprocessed using second-derivative transformation and modeled using partial least squares regression (PLSR) and the ANNs. The ANNs outperformed PLSR, achieving the correlation coefficient (R²) values of up to 0.944 (Sukkary) and 0.927 (Khlass), with corresponding root mean square error of prediction (RMSEP) values of 0.042 and 0.049, and the relative error of prediction (REP < 5%). The best quality retention was observed in the dates stored at −18 °C in pressed semi-rigid plastic containers (PSSPCs), with minimal microbial growth and superior sensory scores. The second-order Qi model showed a significantly better fit (p < 0.05, AIC-reduced) over that of linear alternatives, capturing the nonlinear degradation patterns during storage. The proposed system enables real-time, non-invasive quality monitoring and could support automated decision-making in postharvest management, packaging selection, and shelf-life prediction. Full article

The growing concern over the long-term persistence of plastic waste has driven research into biological methods of breaking down polymers. This study investigated a process that combines physicochemical pretreatment and biodegradation of low-density polyethylene (LDPE) using bacterial strains isolated from commercial compost. Four bacterial strains were genetically identified and classified as Actinomycetes. Exposure of LDPE to these selected strains resulted in a measurable reduction in polymer sample weight, accompanied by alterations in surface hydrophobicity. Furthermore, the chemical modifications at the films’ surfaces were confirmed by the spectra obtained by Fourier transform infrared spectroscopy (FTIR). The microbial colonisation of plastic surfaces plays a key role in the overall biodegradation process. The formation of a biofilm and the subsequent morphological changes on the LDPE surface were revealed by scanning electron microscopy (SEM). The modification of the polyethylene surface by nitric acid treatment was found to be a promising strategy for enhancing the LDPE degradation. The acid-treated films exhibited the greatest weight loss, the greatest increase in carbonyl index values, and the greatest change in hydrophobicity following microbial exposure. Moreover, it was found that biodegradation under these conditions resulted in the lowest levels of phytotoxic byproducts. The transformation of polyethylene surface properties—from hydrophobic to hydrophilic—combined with the presence of oxidized functional groups made it easier for microorganisms to degrade LDPE. Full article

Lotus stems contain cellulose, which can be utilized as a base material for producing green products, specifically degradable plastics. This research investigates the effect of polylactic acid (PLA) blends on cellulose degradable plastics from the lotus stem (Nelumbo nucifera). The mechanical characteristics are as follows: tensile strength of 0.7703–3.3212 MPa, elongation of 0.58–1.16%, Young’s modulus of 78.7894–364.6118 MPa. Compound analysis showed the presence of O-H, C-C, and C=O groups, and the presence of microbial activity in the soil can also lead to the degradation of these groups due to their hydrophilic nature, which allows them to bind water. Thermal analysis within a temperature range of 413.24 °C to 519.80 °C, shows that significant weight loss begins with the formation of crystalline structures. The degradable plastic exhibiting the lowest degree of swelling consists of 1 g of cellulose and 8 g of PLA, resulting in a swelling value of 6.25%. The degradable plastic is anticipated to decompose most rapidly after 52 days, utilizing 2 g of PLA and 7 g of cellulose. This complies with standard requirement, which sets a maximum degradation period of 180 days for polymers. Full article

Plastic pollution in freshwater ecosystems is an increasing environmental concern, prompting the search for biodegradable polymer (BP) alternatives. However, their degradation in natural aquatic environments remains poorly investigated and understood. This four-month in situ study compared the degradation in a lentic freshwater ecosystem of two compostable items, Mater-Bi^® shopping bag and disposable dish, with their respective pure polymer matrices, poly(butylene adipate-co-terephthalate) (PBAT) and polylactic acid (PLA). Additionally, biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and oil-based polypropylene (PP) were also tested. Changes in morphology, chemical composition and thermal and mechanical properties, as well as microbial colonization, were analyzed over time. A validated cleaning protocol was employed to ensure accurate surface analysis. Results showed detectable but limited degradation of pure polymers and their matrices in commercial products after 120 days of immersion with variations observed among polymer materials. Compostable materials exhibited significant leaching of fillers (starch, inorganic particles), leading to morphological changes and fragmentation. PHBV showed the fastest degradation among tested polyesters. PP exhibited only minor surface changes. Microbial colonization varied with polymer structure and degradability, but long-term degradation was limited by polymer properties and the gradual development of the plastisphere. This study highlights that standard laboratory tests may overestimate the environmental degradability of BPs and emphasizes the importance of in situ assessments, careful cleaning procedures and property characterizations to accurately assess polymer degradation in freshwater systems. Full article

In this study, a bio-nanocomposite integrating calcium caseinate, modified starch, and bentonite nanoclay was formulated and synthesized into film form via solution casting. Glycerol was incorporated for plasticization, and polyvinyl alcohol (PVA) was used to enhance the structural and chemical attributes of the material. The addition of PVA and bentonite notably improved the mechanical strength of the casein-based matrix, showing up to a 30% increase in tensile strength compared to similar biopolymer formulations. Water vapor permeability was significantly reduced when compared to previously reported casein–starch formulations, evidencing the barrier-positive effects of bentonite nanostructures. The microbial analysis confirmed that the quantity of bacterial colonies remained within permissible levels for non-antimicrobial biodegradable films; however, further antibacterial evaluations are advised. Biodegradability testing showed a consistent degradation trend, with full disintegration extrapolated to occur around 13 weeks under natural soil conditions. This study offers exploratory insight into the development of functional and biodegradable films using biopolymer blends and nanoclay suspensions, highlighting their potential in sustainable food packaging applications. Full article