Search Results (211)

The exponential growth of the global textile industry, largely driven by the demand for synthetic polymers such as poly(ethylene terephthalate) (PET), polyamides, and polyurethanes, has led to severe environmental consequences, notably the accumulation of persistent microplastics and solid waste. While conventional mechanical and chemical recycling methods are widely employed, they are often hindered by harsh processing conditions and the deterioration of material properties. Consequently, there is a critical need for sustainable end-of-life management strategies. This review provides a comprehensive analysis of the biodegradability of synthetic textile fibres, with a primary focus on emerging biotechnological and enzymatic recycling approaches. It systematically examines the intrinsic polymer characteristics that govern biodegradation—including molecular orientation, crystallinity, functional groups, and fibre chemistry—as well as extrinsic factors such as textile finishings, yarn twist, polymer blends, and chemical additives. Furthermore, the current landscape of microbial and enzymatic degradation routes is critically assessed, highlighting the specific mechanisms of biocatalysts (e.g., lipases, cutinases, PETase, and MHETase) in depolymerising complex synthetic matrices into recoverable monomers. Finally, this review identifies the existing literature gap between bulk plastic and textile-specific biodegradation, discussing future perspectives. By bridging polymer science and textile engineering, this work underscores the potential of enzymatic recycling to close the loop in synthetic fibre production and advance the transition toward a circular economy. Full article

Salinity is a dominant ecological driver shaping microbial community structure and function in hypersaline environments. Here, we investigated transcriptional responses to rapid salinity fluctuations using metatranscriptomic analyses of an intermediate-salinity brine sample from the Santa Pola solar salterns (Alicante, Spain). To this end, two experimental conditions were applied: salinity increase (12.4% to 17%) and salinity dilution (12.4% to 7%). Differential gene expression, functional enrichment, and protein isoelectric point (pI) distributions were analyzed to characterize osmoadaptive mechanisms. Salinity increase triggered a stress-dominated response characterized by upregulation of compatible solute biosynthesis (e.g., glycine betaine and ectoine), protein turnover, and chaperone activity, alongside repression of translation, energy metabolism, and transport systems. In contrast, salinity dilution induced metabolic reactivation, including enhanced translation, energy production, and osmolyte degradation pathways, indicating recovery from osmotic stress. Functional shifts were accompanied by changes in proteome physicochemical properties, with increased salinity promoting a shift toward higher pI proteins, consistent with salt-out strategies. These findings reveal a highly dynamic and asymmetric transcriptional plasticity, where osmotic upshift imposes stronger constraints than downshift, driving coordinated metabolic reprogramming and proteome restructuring in intermediate-salinity microbial communities. Full article

Microplastic pollution has become a significant environmental concern due to its persistence and widespread impact across ecosystems. These plastic particles (1 μm to 5 mm), originating from larger plastic debris or industrial sources, accumulate in diverse habitats, affecting biodiversity and human health. Microplastics resist natural degradation, posing challenges to both ecological sustainability and waste management strategies. Although numerous studies have explored microbial degradation, most existing research focuses primarily on bacteria, leaving the role of filamentous fungi comparatively underexplored. This represents a significant research gap, because fungi secrete a variety of extracellular enzymes, including laccases, peroxidases, and esterases, which play crucial roles in the breakdown of synthetic polymers. These enzymes facilitate the depolymerization of microplastics by targeting polymer chains and increasing their susceptibility to further microbial degradation. However, the underlying enzymatic mechanisms and their effectiveness in microplastic remediation remain insufficiently characterized. Here, we critically review the potential of filamentous fungi for microplastic biodegradation, emphasizing their oxidative and hydrolytic enzyme systems, biosurfactant production, and mechanisms of adsorption and mineralization. The novelty of this review lies in consolidating the most recent mechanistic insights into fungal-driven depolymerization pathways, integrating them with advances in genetic engineering, bioprocess scale-up, and regulatory perspectives, areas rarely combined in previous reviews. We identify current limitations related to environmental applicability, enzyme accessibility, and the lack of standardized protocols, and propose strategies to overcome these challenges through enzyme immobilization, microbial consortia design, and synthetic biology approaches. By addressing these gaps, filamentous fungi may contribute to the development of sustainable strategies for plastic pollution mitigation and support circular economy approaches toward polymer biodegradation. Full article

Plastic pollution has become an increasingly severe global environmental issue, highlighting the urgent need for efficient and sustainable biodegradation strategies. In this study, an enriched gut microbial consortium, NE-01 derived from Tenebrio molitor, exhibited significant degradation activity toward polystyrene (PS), polyethylene (PE), and polyethylene terephthalate (PET). Metagenomic sequencing revealed that Pseudomonas and Proteobacteria were the dominant taxa, maintaining high community diversity and providing a microbial foundation for the degradation of plastics and other complex organic compounds. Functional annotation and metabolic pathway analysis indicated that xenobiotic biodegradation and metabolism occupied a large proportion of the metabolic network, suggesting the consortium’s potential for degrading exogenous pollutants. Several key genes associated with the degradation of aromatic and halogenated compounds, such as benzoate, toluene, styrene, and bisphenol A, were identified. Metabolic reconstruction further suggested possible degradation pathways for PS, PE, PET, and the plasticizer di(2-ethylhexyl) phthalate (DEHP). This study preliminarily demonstrated that the T. molitor gut-derived microbial consortium harbors multiple plastic-degrading genes and provides a theoretical basis for developing green, microbe-based strategies for plastic degradation. Full article

Soil biofilms are structured, dynamic microbial consortia embedded within extracellular polymeric substances that regulate microscale physicochemical heterogeneity and drive biogeochemical transformations in soils. Despite increasing interest in biofilm-mediated remediation, current reviews have largely examined microbial ecology, engineered biofilm functions, and predictive modelling independently, limiting systems-level understanding of pollutant fate in complex soils. This review, therefore, proposes a revised conceptual framework integrating biofilm ecology, synthetic biology, and AI-driven predictive modelling to improve mechanistic and predictive understanding of emerging pollutant detoxification. Emerging pollutants, including pharmaceuticals, pesticides, per- and polyfluoroalkyl substances, micro- and nanoplastics, and heavy metals, exhibit persistence, bioaccumulation, and mixture-dependent effects that challenge conventional remediation strategies. Biofilm matrices function as reactive interfaces facilitating adsorption, sequestration, and enzymatic transformation, while steep redox and nutrient gradients support metabolically diverse processes such as cometabolism, syntrophic degradation, and biomineralisation. Increasing evidence indicates that quorum sensing, horizontal gene transfer, and low-abundance microbial taxa contribute significantly to adaptive responses and functional plasticity within biofilms. Advances in high-resolution imaging, spatial multi-omics, and microfluidic platforms have resolved previously inaccessible biofilm architectures and processes; however, integration with machine learning and process-based modelling remains limited, restricting field-scale prediction of pollutant behaviour and remediation outcomes. Synthetic biology enables targeted optimisation of biofilm functions, whereas AI-driven models enhance prediction of contaminant transport, transformation, and detoxification. Soil biofilms function both as sinks and catalytic hotspots, and resolving this duality through a predictive, systems-level framework represents a major advance beyond existing descriptive reviews. Full article

This study highlights the strong ability of a new bacterial strain, Hafnia paralvei UUNT_MP29, isolated from the gastrointestinal tract (GIT) of common carp (Cyprinus carpio), to break down polystyrene (PS). As an omnivorous bottom feeder, C. carpio is constantly exposed to microplastics, creating a unique environment that favors the evolution of specialized microbiota capable of degrading polymers. Genomic analysis of the isolate identified key homologs involved in xenobiotic breakdown, including alcohol dehydrogenase (Adh), 3-hydroxybutyrate dehydrogenase (HDH), and a small glutamine-rich tetratricopeptide repeat-containing protein (SGTA), showing a strong metabolic system for processing long-chain hydrocarbons. Growth experiments showed the strain quickly adapted, reaching maximum cell density and forming mature biofilms by Day 16. Gravimetric analysis confirmed that H. paralvei UUNT_MP29 uses PS as its primary carbon source, with a significant weight loss of 16.76% over 16 days. Kinetic modeling indicated the degradation follows first-order kinetics (R² = 0.9243) with a high degradation rate constant (k) of 0.2078 day⁻¹. Surface analyses using FTIR and SEM confirmed extensive oxidative changes, as evidenced by the rising Carbonyl Index and surface erosion. TGA also showed reduced thermal stability of the treated polymer, suggesting microbial chain scission. These findings demonstrate the strong degradative ability of H. paralvei UUNT_MP29 and highlight the GIT of plastic-exposed aquatic animals as a promising area for discovering powerful biocatalysts for microplastic cleanup. Full article

Microbial biodegradation represents a promising approach to addressing global plastic pollution, yet the metabolic pathways and environmental origins of polymer-degrading microorganisms remain incompletely characterized. This review synthesizes current knowledge on biodegradation mechanisms across major polymer classes and identifies key environmental reservoirs harboring native plastic-degrading microbiota. Biodegradation pathways differ fundamentally according to polymer chemistry. Polyesters such as PET undergo hydrolytic cleavage by PETases and MHETases, releasing terephthalic acid and ethylene glycol for assimilation via the β-ketoadipate pathway and the TCA cycle. Biodegradable polyesters (PLA, PBAT, PHAs, PCL) are similarly hydrolyzed by cutinases, lipases, and depolymerases. In contrast, polyolefins (PE, PP) and polystyrene lack hydrolyzable bonds and require oxidative attack by laccases, peroxidases, and alkane monooxygenases, followed by β-oxidation to acetyl-CoA. Three principal environmental reservoirs supply plastic-degrading microorganisms: contaminated ecosystems including landfills and the plastisphere; soil microbiota contributing ligninolytic fungi and actinomycetes; and compost environments yielding thermostable enzymes such as leaf-branch compost cutinase. Across all environments, microbial consortia demonstrate superior degradation efficiency compared to single-species cultures, reflecting the enzymatic complexity required for complete polymer mineralization. Understanding these pathways and their environmental origins provides a foundation for biological plastic waste management strategies. Full article

Background: Microplastics, derived from plastic degradation and industrial sources, are widely detected in aquatic environments and food systems, posing increasing environmental and ecological risks. Aims: This study aimed to investigate how microplastics affect host physiology and gut microbiota, as well as determine whether microbiota changes actively modulate host responses. Methods: Using A. salina as a model organism, we combined physiological assays, oxidative stress analysis, gut microbiome profiling, and bacterial functional validation under chronic polystyrene microplastics exposure. Results: Polystyrene microplastics accumulated in the gut and significantly impaired growth and survival, accompanied by reduced digestive enzyme activity and immune function, as well as increased oxidative stress, indicating disruption of physiological homeostasis. Microplastic exposure also induced microbial dysbiosis, characterized by decreased diversity and compositional shifts. Functional assays demonstrated that a bacterium enriched under exposure, Pseudomonas knackmussii, partially restored host growth and physiological functions while reducing oxidative stress. Conclusions: These findings demonstrate that gut microbiota are not only altered by microplastic exposure but also actively modulate host responses to environmental stress, providing new insight into microbiota-mediated resilience under pollutant stress. Full article

Petrochemical-based plastics are widely used due to their convenience and low cost, with polyethylene (PE) being the most produced globally. However, the lack of efficient and sustainable treatment methods for conventional plastic wastes has led to severe environmental pollution. A new fungus strain capable of degrading PE was isolated from soil samples collected at a waste disposal site in Henan province and identified as Aspergillus sydowii W144. After 30 days of incubation under solid-state culture conditions, the strain demonstrated significant oxidative depolymerization of low-density polyethylene (LDPE). FTIR results revealed a substantial increase in the carbonyl index of the LDPE film, while differential scanning calorimetry (DSC) analysis detected an enhanced crystallinity in the LDPE film. Notably, distinct pitting and erosion marks were observed on the surface of LDPE film using scanning electron microscopy (SEM). Quantitative analysis showed a weight loss rate of 6.39% and a reduction in Weight-Average Molecular Weight (Mw) by 50.93%. Among currently identified PE-degrading strains polyethylene, A. sydowii W144 exhibits particularly outstanding depolymerization efficiency, especially on untreated PE. Based on the whole-genome data of A. sydowii W144, a preliminary model of the putative polyethylene degradation pathway in A. sydowii W144 was constructed through homology-based sequence analysis and by referencing previously reported polyethylene degradation pathways. Laccase/multicopper oxidase plays a key role in the initial oxidation of PE. Heterologous expression of the candidate gene laccase4 in Pichia pastoris yielded an active enzyme (~56 kDa) with a laccase activity of 460 U/L, confirming its functionality. This study provides a novel microbial resource and potential enzymatic tools for PE biodegradation. The strain exhibits a promising application in complex ecosystems for PE pollution. IMPORTANCE: The polyethylene-degrading strain A. sydowii W144 isolated in this study exhibits highly efficient depolymerization capabilities, particularly under solid-state culture conditions. Genomic sequencing analysis enabled the construction of a potential polyethylene (PE) degradation pathway and facilitated the identification of key laccase and multicopper oxidase genes involved in this process. The isolation of this novel strain enriches the microbial resources available for PE waste treatment and offers new insights into the mechanisms of plastic biodegradation. Full article

Organic waste management remains a pressing environmental and economic challenge, particularly in small-scale or domestic contexts where access to industrial composting technologies is limited. This study investigates the performance of the BSG-2 fermenter, a low-cost aerobic system designed to convert brewery spent grain (BSG) and vegetable waste into nutrient-rich compost through solid-state fermentation. The fermenter, constructed from food-grade plastic, relied on intermittent forced aeration, and manual temperature and pH control to sustain microbial activity. Temperature, pH, and substrate degradation were monitored throughout a complete fermentation cycle. The system achieved consistent bio-thermal performance with peak temperatures of approximately 32 °C and a substrate volume reduction of 30–40%, confirming active microbial metabolism and substantial organic matter degradation. Minimal odor generation and low energy input highlighted the fermenter’s environmental suitability. While occasional anaerobic pockets and limited heat retention were observed, these limitations could be addressed through improved insulation and automated aeration. The sustained mesophilic heat generation observed in the system may also present opportunities for low-grade thermal recovery in small-scale applications, such as localized environmental conditioning, although the magnitude of heat produced is limited. Overall, the BSG-2 fermenter demonstrates a feasible, replicable approach to valorizing organic waste into compost and sustained mesophilic heat generation using simple, accessible materials, contributing to circular economy strategies and sustainable small-scale waste management. Full article

Soil degradation in both agricultural and urban environments is accelerating due to intensive land use, plastic pollution, construction practices, and climate change, threatening ecosystem stability, food security, and carbon storage capacity. This review synthesizes current advances in biopolymeric materials as regenerative alternatives to conventional soil management approaches. Biopolymers derived from natural sources—including polysaccharides, proteins, and lignin-based compounds—are examined for their multifunctional roles in improving soil structure, enhancing water retention, optimizing nutrient delivery, stabilizing slopes, and supporting pollutant immobilization. Recent developments highlight the emergence of stimuli-responsive hydrogels, controlled-release fertilizer matrices, and composite soil conditioners capable of simultaneously addressing water stress, salinity, erosion, and contamination. In parallel, biodegradable agricultural films and in-soil degradable materials offer pathways to reduce microplastic accumulation while maintaining agronomic performance. Beyond agriculture, bio-based construction materials and bio-receptive design strategies extend biopolymeric interventions into the built environment, promoting soil permeability, microbial diversity, and circular material flows. The review emphasizes the need for context-specific formulation, long-term field validation, and life-cycle assessment to ensure environmental safety and scalability. By integrating soil science, polymer chemistry, and regenerative design, biopolymeric systems are described here as tools for restoring soil health and fostering resilient urban–rural ecosystems under conditions of environmental change. Full article

Micro- and nanoplastics (MNPs) have now been detected in human blood, placenta, and arterial tissue, yet the oral cavity has received strikingly little mechanistic attention despite serving as a primary portal of environmental exposure and a local site of polymer generation from dental and oral-care materials. This narrative review addresses that gap from an environmental microbiology perspective, synthesizing recent literature on periodontal disease, chronic low-grade inflammation, oral biofilms, dental materials, microbial–plastic interactions, and systemic chronic disease risk. Unlike prior reviews, we apply an explicit three-tier evidentiary framework (established, plausible, unproven) that distinguishes what is directly demonstrated from what is biologically plausible but unproven, and we situate the periodontal environment specifically as a particle-retention and inflammatory-amplification niche. The strongest direct oral evidence shows that human dental calculus harbors at least 26 microplastic types, dominated by polyamide (41.4%), polyethylene (32.7%), and polyurethane (7.0%). Polyethylene isolated from calculus induces cytotoxicity, apoptosis, impaired migration, NF-κB activation, and upregulation of IL-1β and IL-6 in human gingival fibroblasts. From a microbiological standpoint, oral organisms actively degrade methacrylate dental polymers, and the degradation products of these polymers reciprocally modulate oral bacterial virulence gene expression. Across experimental systems, MNPs activate oxidative stress, inflammasome signaling, macrophage polarization, and barrier dysfunction, pathways that overlap extensively with periodontal pathobiology. Adjacent environmental microbiology demonstrates that plastic-associated biofilms enhance extracellular polymeric substance production, quorum sensing, pathogen persistence, and antibiotic resistance gene transfer, supporting a plausible but not yet validated oral plastisphere within plaque and calculus. We argue that periodontitis should be reconceptualized as a chronically inflamed particle-processing interface that may increase local MNP retention, cellular reactivity, and systemic inflammatory spillover, with implications for cardiovascular, metabolic, and other chronic disease risk pathways. Current evidence does not yet prove that environmental MNP exposure causes human periodontitis, and that evidentiary boundary is maintained throughout. A priority research agenda is proposed, centered on contamination-controlled subgingival biomonitoring stratified by periodontal status, spatially resolved multi-species biofilm models, polymer source attribution, and longitudinal clinical studies linking oral plastic burden to inflammatory and systemic outcomes. Full article

Plastic pollution is a global environmental crisis, and microbial degradation represents a promising remediation strategy. While bacteria have been widely studied, yeasts offer unique advantages for plastic degradation due to their metabolic versatility, stress tolerance, and enzymatic capabilities. However, plastic degradative yeasts have not been reviewed comprehensively. Although several yeasts capable of degrading polyethylene terephthalate (PET) or polyethylene (PE) have been reported (e.g., Moesziomyces antarcticus, Candida tropicalis, Yarrowia lipolytica and Rhodotorula mucilaginosa), degraders of other plastic types are less studied. Although some yeasts can assimilate carbon from plastics, the diversity of yeasts capable of participating in plastic mineralization remains vastly underexplored. In recent years, yeast cell surface display systems for bacterial PETase and fungal cutinase have been developed, demonstrating promising PET degradation efficiency. However, PETase is feedback-inhibited by the intermediate product mono(2-hydroxyethyl)terephthalate (MHET). Systems synergizing PETase with MHETase have shown superior stability during long-term PET degradation and enable large-scale depolymerization of PET waste. For high-crystallinity PET, fungal hydrophobins can be used to modify the surface hydrophobicity of PETase-displaying yeast cells, facilitating their attachment to hydrophobic PET surfaces and ultimately enhancing the degradation efficiency of the whole-cell biocatalyst. Limitations of current research and future directions are also discussed. Full article

Microplastics (MPs) are emerging pollutants that affect soil–microbe interactions in paddy ecosystems. Periphytic biofilms (PBs) are complex microbial consortia that ubiquitously distribute at the soil–water interface of paddy ecosystems, playing essential roles in nutrient cycling and pollutant migration. However, whether MPs affect the community composition of PBs remains largely unknown. This microcosm study investigated the effects of three types of MPs (polyacrylonitrile, PAN; polyethylene, PE; and polyethylene terephthalate, PET) on the community characteristics of PBs via high-throughput sequencing (16S/18S rRNA) technology. Results showed that the addition of all MPs significantly increased the biomass and chlorophyll-a content of PBs, with PAN inducing the maximum increase (by 331.9% and 128.6%). However, all MPs had no significant effect on the PB α-diversity of bacterial and eukaryotic communities (p > 0.05). As for PB composition, PAN and PET increased the relative abundance of Cyanobacteria, Proteobacteria and Holozoa, PE increased that of Cyanobacteria, Bacteroidota and Blastocladiomycota, and all MPs decreased the relative abundance of Chloroflexi, Actinobacteriota and Basidiomycota. Furthermore, PET decreased the predicted functional potential of natural polymer degradation (cellulolysis, ligninolysis, xylanolysis, ureolysis), nitrogen fixation and nitrate ammonification, while PE increased predicted potential for plastic degradation, nitrate reduction and denitrification. Co-occurrence network analysis suggested that the PE network showed higher connectivity and lower modularity, while the PAN network showed higher modularity. This study advances our understanding of soil MPs–microbe interactions under high-concentration conditions. It also suggests that PB community characteristics may serve as potential bioindicators for soil MP pollution. Full article

To enhance the engineering performance of fine-grained composite soils with unbalanced particle gradation, high plasticity, and poor water stability, a synergistic stabilization strategy combining particle structure regulation and microbially induced calcium carbonate precipitation (MICP) was proposed. The particle size distribution and fundamental engineering properties of a titanium gypsum–clay (TSC) composite soil were first optimized through systematic single-factor blending tests. The results indicate that a TS:C ratio of 60:40 significantly improved gradation characteristics, reduced plasticity, and enhanced both compaction behavior and load-bearing capacity. Based on the optimized gradation framework, MICP treatment was subsequently introduced to further enhance water stability. The effects of key parameters, particularly the type of calcium source, on the evolution of water stability were systematically investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to elucidate the underlying reinforcement mechanisms. The results demonstrate that the water stability coefficient increased markedly from 0.35 to 0.83 following MICP treatment, while strength degradation under water immersion was effectively mitigated. Microscopic observations reveal that microbially precipitated calcite fills pore spaces and forms a continuous cementation network via particle bridging and interfacial bonding, leading to an approximately 32% reduction in porosity. Overall, the proposed synergistic strategy offers an effective and sustainable approach for improving the water stability and structural integrity of complex fine-grained composite soils. Full article