Search Results (549)

The growing interest in bio-based and biodegradable polymer composites reinforced with agricultural waste reflects global efforts to reduce dependence on fossil resources and improve the sustainability of materials. However, biocomposites are not necessarily more sustainable, and their environmental performance requires careful life cycle assessment (LCA). This review critically analyses recent LCA studies of biodegradable biocomposites reinforced with agricultural waste, focusing on methodological choices, data quality, results and limitations. A systematic literature review was conducted using the Scopus database, focusing on studies from the last five years. Selected studies were examined using a structure consistent with ISO 14040, with defined data extraction categories and key questions. The analysis shows that although biocomposites often demonstrate advantages in terms of climate change and fossil resource depletion compared to traditional materials, the results vary significantly depending on the definition of the functional unit, geographical context, processing pathways, and data assumptions. Limitations include reliance on laboratory data, uncertainties, incomplete system boundaries, inconsistent allocation methods, and limited end-of-life (EoL) modelling. Overall, the review highlights the need for improved data quality, performance-based functional units, geographically representative inventories, and more standardised LCA practices to ensure meaningful comparisons and support the sustainable development of biocomposites. Full article

The environmental persistence of post-consumer plastics remains a critical challenge due to their chemical stability, the presence of additives, and prior environmental weathering. This study evaluates the partial biodegradation and chemical transformation of post-consumer low-density polyethylene (LDPE) and expanded polystyrene (EPS) by Tenebrio molitor larvae under uncontrolled environmental conditions. Four diets were tested, including LDPE+S and EPS+S (polymers supplemented with wheat bran), to assess the influence of a co-substrate on larval performance and polymer transformation. Fourier-transform infrared spectroscopy (FTIR) revealed the emergence of oxygen-containing functional groups (–OH and C=O) in the frass, which were absent or negligible in pristine materials, indicating oxidative modification of the polymer matrix. Gel permeation chromatography (GPC) revealed pronounced reductions in number-average molecular weight (Mn) and increased polydispersity for EPS-derived fractions, consistent with heterogeneous chain scission and partial depolymerization. For LDPE, GPC evidenced the formation of THF-soluble, low-molecular-weight polymer-derived fragments, indicating fragmentation despite the inability to quantify pristine LDPE due to its insolubility in the mobile phase. Gas chromatography–mass spectrometry (GC–MS) identified aromatic hydrocarbons, phthalate esters, organosiloxanes, and fatty acid derivatives, reflecting both degradation intermediates and migrated additives from post-consumer plastics. Together, these results provide integrated evidence that Tenebrio molitor can induce chemical transformation of post-consumer LDPE and EPS under non-controlled environmental conditions, offering mechanistic insight into a biologically mediated degradation pathway that is directly relevant to realistic plastic waste scenarios. Full article

Ketoprofen is a widely prescribed non-steroidal anti-inflammatory drug whose extensive global use, combined with limited biodegradability, has led to its increasing detection as a micropollutant in aquatic and terrestrial environments. Incomplete removal during wastewater treatment results in its continuous release into surface waters and soils, creating conditions for chronic, low-dose exposure of non-target organisms. This review synthesizes current knowledge on the physicochemical characteristics of ketoprofen, its mechanism of action, environmental occurrence, degradation pathways, and ecotoxicological effects. Particular emphasis is placed on biological and photochemical transformation processes that influence ketoprofen persistence and toxicity. While the acute toxicity of ketoprofen has been relatively well documented, data on chronic toxicity remain scarce, despite growing evidence that long-term exposure may pose significant ecological risks. Studies indicate that low environmental concentrations can induce hormetic responses in animals and plants, whereas higher levels may cause cellular damage associated with oxidative stress, affecting organisms ranging from microorganisms to vertebrates and vascular plants. By integrating available data on ketoprofen degradation and toxicity, this review highlights critical knowledge gaps regarding its chronic ecotoxicity and underscores the need for systematic environmental monitoring and the development of effective degradation strategies to mitigate risks to non-target organisms. Full article

Linear alkylbenzene (LAB) is the main raw material used to make biodegradable detergents, and its production process is based on aromatic alkylation. HY zeolites that have undergone controlled dealumination and desilication have led industrial standards amongst solid acid catalysts because of their controllable acidity and hierarchical pore structure. Coke formation in such systems can assume a dual role, which is dependent on its condition. Though the over-deposition is known to cause deactivation by blocking the micropores, Bronsted acid-site masking, and diffusion collapse, the low-level deposition could also be done to increase the monoalkylate selectivity by the pore mouth catalysis, steric modulation, and selective suppression of secondary alkylation pathways. The critical review is done on the structural-kinetic interaction that determines the coke evolution in HY-based catalysts. In order to moderate the acid-site density and enhance hydrothermal stability, dealumination (Si/Al optimization of about 2.5 to 30–100) occurs, but to reduce deep-pore coke formation, desilication (interconnected mesopores) is created. The bimodal porosity and regulated acidity are found to be synergistic, as hierarchical HY zeolites produced through successive cycles of steam and alkaline treatments not only show LAB selectivity in excess of 90% but also exhibit much longer catalyst lifetimes. Quantitative research on the beneficial coke regime revealed that it was composed of about 36 wt% hydrogen-rich species, which were localized at the pore mouths, hence enhancing monoalkylation selectivity by 15–40%. Beyond a critical transition window (e.g., 8–12 wt.%), coke formation to condensed polyaromatic and graphitic products leads to fast deactivated coke formation, which is due to percolation limits and transport-controlled kinetics. More advanced techniques of characterization of the coke, e.g., temperature-programmed oxidation (TPO), ²⁷Al MAAS NMR, and UV-Raman spectroscopy, indicate how the coke is changed to highly structured graphitic deposits of high oxidation activation energy. Activity recovery of 85–98% is obtained in regeneration processes, including controlled oxidative calcination, microwave-based and plasma-based processes, and thermal management protocols, and it would be determined by the chemistry of the coke, its spatial distribution, and the regeneration protocols. This paper has developed a mechanistic coke control system by cross-tuning the acidity and development of an effective pore network, which led to a sustainable aromatic alkylation reaction with minimal activity loss, high selectivity, and long life. Full article

Microcystins (MCs), a group of potent hepatotoxins from cyanobacterial blooms, threaten global water security due to the resistance to conventional treatment processes and multi-organ toxicity to human. This study innovatively proposed a novel sequential process combining UV irradiation with biodegradation by Sphingopyxis sp. m6 for efficient microcystin-LR (MC-LR) removal. Results revealed that sequential UV-C pretreatment followed by Sphingopyxis sp. m6 biodegradation achieved complete degradation of 1 mg/L of MC-LR within 1 h of the biological phase, drastically reducing the treatment time compared to biodegradation alone (5 h). Mechanistic investigation revealed that low-dose UV-C (50 mJ/cm²) pretreatment induced MC-LR photoisomerization consistently with previously reported Adda geometric isomers. These photoisomers, along with residual parent MC-LR, were subsequently mineralized by Sphingopyxis sp. m6. Enzymatic pathway analysis confirmed a dual-pathway degradation, where Mlr enzymes processed both the native toxin and its isomeric forms, leading to a series of linearized peptides and Adda-derived products. Critically, the process achieved efficient detoxification, as confirmed by the restoration of HepG2 cell proliferation and protein phosphatase 2A activity. Moreover, response surface methodology optimized the key parameters (31.49 °C, pH of 7.36, 0.23 mg/L) for the highest degradation efficiency. This work provides an energy- and cost-efficient strategy for MC-LR remediation and elucidates the molecular mechanism of UV-induced photoisomerization facilitating subsequent biodegradation. Full article

Plant defence elicitors have emerged as pivotal components of sustainable fruit crop protection, aligning with One Health principles by reducing chemical residues while enhancing ecosystem and human health. These exogenous agents—ranging from phytohormones, peptides, and cell-wall fragments to botanical extracts—activate or prime innate immune responses in fruit crops through pattern-triggered immunity (PTI), systemic acquired resistance (SAR), and induced systemic resistance (ISR) pathways. Over the last decade, advances in receptor biochemistry, genomics, metabolomics, and epigenetics have transformed this field. Recent mechanistic advances reveal that oligosaccharide elicitors derived from chitosan and laminarin are perceived by membrane-localised pattern recognition receptors (PRRs) that confer broad-spectrum resistance against fungal, bacterial, and viral pathogens in fruits. By contrast, no specific protein receptor has been identified for harpin proteins, the emerging evidence indicating that harpin perception may occur through direct interaction with plasma-membrane lipids or lipid-associated proteins. The One Health approach is supported by elicitors, biodegradability, minimal environmental persistence, and the ability to reduce synthetic fungicide usage by 30–70%. However, challenges remain regarding batch-to-batch variability, sensory acceptance due to bitter compounds, regulatory hurdles for novel food approvals, and the need for optimised application protocols that consider the fruit genotype and developmental stage. The future integration of nanotechnology for targeted delivery, the artificial-intelligence-driven screening of active molecules, and synergistic combinations with biocontrol agents promises to overcome these limitations, positioning plant defence elicitors as cornerstone tools for resilient, health-promoting fruit production systems. Full article

The rapid growth of synthetic textile production has intensified the release of micro- and nanoplastics (MPs/NPs) into aquatic environments, primarily through industrial effluents and domestic laundering. Textile-derived microplastics, especially polyester fibers and polymeric coating fragments, constitute a significant fraction of plastic contamination in wastewater systems. Although wastewater treatment plants (WWTPs) can remove a large proportion of MPs, substantial quantities accumulate in sewage sludge, raising concerns about long-term environmental persistence and secondary release pathways. This review critically examines the sources, classification, and release mechanisms of textile-based micro- and nanoplastics, including fibrous debris and coating-derived fragments. Then it focuses on current identification and removal technologies, such as sedimentation, coagulation/flocculation, electrocoagulation, flotation, membrane filtration, adsorption, and biodegradation, and on the emerging strategy of converting recovered microplastics into value-added porous carbon materials via hydrothermal treatment and pyrolysis. Carbonized microplastics exhibit high surface area and adsorption capacity for dyes, heavy metals, and organic pollutants, offering a circular approach that simultaneously mitigates plastic pollution and enhances wastewater treatment efficiency. By integrating source control, optimized removal technologies, and carbonization-based valorization, this review proposes a dual-benefit framework that transforms textile-derived microplastic waste from an environmental liability into a functional resource for sustainable water purification. Full article

Polylactide (PLA) has become widely adopted across biomedical, packaging, and manufacturing sectors due to its biodegradability and renewable sourcing. However, the rapid growth in PLA consumption has created urgent challenges related to waste management and the cleaning of processing equipment. This study investigates glycolysis as a promising chemical depolymerization pathway for PLA recycling and in situ reactor cleaning. A systematic analysis of four glycolysis agents (GA) (ethylene glycol, diethylene glycol, propylene glycol, and glycerol) was performed across molar PLA:GA ratios from 1:0.125 to 1:4 at 220 °C, targeting the efficient conversion of high-molecular-weight PLA (Mn ≈ 165 kDa) into low-molecular-weight oligomers. Gel permeation chromatography (GPC) demonstrated that propylene glycol exhibited the highest depolymerization efficiency, yielding oligomers with Mn as low as 200 g·mol⁻¹ even at minimal glycolysis agent ratios, while glycerol produced hydroxyl-rich oligomers optimal for subsequent lactide synthesis. Hydroxyl value (HV) measurements showed excellent agreement with theoretical values (<5% deviation), allowing us to make an assumption about an approximate, close to near-quantitative con-version. Glycolysis products with Mw below 400 g·mol⁻¹ displayed excellent water solubility, making them particularly attractive for reactor cleaning applications. Using glycerol-derived (GL) oligomers (PLA:GL = 1:0.25), purified L-lactide with a melting point of 98.1 °C and high purity (>99%) was obtained through thermocatalytic depolymerization and five recrystallization cycles, as confirmed by ¹H nuclear magnetic resonance (¹H NMR) and differential scanning calorimetry (DSC) analyses. The recovered lactide’s high purity renders it suitable for ring-opening polymerization, enabling closed-loop PLA recycling schemes. Overall, glycolysis emerges as a highly promising chemical recycling route complementary to hydrolysis and pyrolysis: propylene glycol maximizes depolymerization efficiency for cleaning applications, while glycerol optimizes oligomer functionality for lactide recovery and advanced material synthesis. Our results provide practical guidelines for selecting glycolysis agents and conditions for cleaning and recycling applications. Full article

Paint manufacturing wastewater contains complex mixtures of solvents, resins, surfactants, pigments, and polymeric additives that result in high chemical oxygen demand (COD), toxicity, and poor biodegradability. Conventional physicochemical treatment provides limited removal of dissolved organics, and the pollutant-level behavior of paint effluents during biological treatment remains insufficiently characterized. This study addresses this gap by evaluating a sequential anaerobic–aerobic batch process treating three distinct synthetic paint wastewater samples. This study is a comparative investigation of sequential biological treatment across multiple paint wastewater variants, combined with high-resolution LC–MS to track compound-level transformations. Treatment performance was assessed through COD removal, biogas generation, pH and redox behavior, and LC–MS profiling of organic contaminants. The anaerobic stage achieved 70–95% COD removal depending on wastewater type. Aerobic polishing increased overall removal efficiencies, while PWW3 exhibited reduced stability during extended operation. LC–MS analysis showed substantial decreases in the number and intensity of chromatographic peaks and demonstrated degradation of phthalates, glycol ethers, organophosphate plasticizers, and solvent-derived compounds. The study provides integrated performance- and pollutant-level assessment of sequential anaerobic–aerobic treatment of paint wastewater and demonstrates the influences of wastewater heterogeneity in biological degradation pathways. Full article

Polyvinyl alcohol (PVA)-based films are promising biodegradable alternatives to petroleum-derived plastics; however, their high rigidity and moisture sensitivity limit practical applications. In this study, PVA/carnauba wax (CW) films were prepared via solution casting and systematically modified using four plasticizers: glycerol (GLY), sorbitol (SOR), glucose (GLU), and sucrose (SUC), at concentrations of 0.1–0.5% (v/w, relative to PVA). Thermal analysis showed that GLY and SOR effectively reduced the glass transition temperature from 52.35 °C (control) to as low as 49.14 °C (0.2% GLY) and 50.70 °C (0.4% SOR), while SUC and SOR plasticized films exhibited improved thermal stability, with the highest melting temperature observed for 0.3% SUC (80.6 °C). SEM micrographs revealed that GLY at moderate concentrations (0.2–0.3%) produced the most homogeneous film morphology, whereas SUC at higher concentrations led to surface roughness and phase separation. Water contact angle measurements showed increased surface hydrophobicity at low plasticizer contents, with 0.1% GLY and 0.2% GLU exhibiting contact angles above 100° compared to the control film (<90°). Mechanical testing demonstrated that SUC at 0.2% had the highest tensile strength (3.03 MPa) compared to 0.73 MPa (control), while GLY at 0.3% yielded the highest elongation at break (9.26%), compared to 0.62% for the unplasticized film. These results demonstrate that precise control of plasticizer type and concentration enables effective tuning of PVA/CW film properties, offering a viable strategy for designing biodegradable films tailored for packaging and agricultural applications. Full article

Biological wastewater treatment relies primarily on activated sludge and anaerobic digestion for the removal of organic matter. In urban wastewater treatment plants discharging into eutrophication-sensitive environments, the simultaneous removal of carbon, nitrogen, and phosphorus is required to meet increasingly stringent discharge limits. Under these conditions, the transformation of complex organic matter into volatile fatty acids (VFAs) represents a more efficient strategy than complete mineralization, as biodegradable carbon is essential to sustain biological nitrogen and phosphorus removal processes. In this study, an anaerobic sequencing batch reactor was operated under acidogenic conditions to promote the conversion of organic matter into VFAs. For the first time, this study demonstrates how temperature-controlled acidogenic pretreatment can reliably supply biodegradable carbon to support efficient downstream nitrogen and phosphorus removal in municipal wastewater treatment. A kinetic model was developed to describe the temporal evolution of the different carbon fractions involved in anaerobic digestion, including biodegradable and non-biodegradable organic matter, intermediate compounds, short-chain volatile fatty acids, and biogas. The model assumes first-order kinetics and constant biomass concentration and was successfully validated against experimental data, with deviations below 10%. Estimated kinetic constants exhibited a strong temperature dependence, particularly for hydrolysis and acidogenic pathways, whereas methanogenic steps showed lower sensitivity. Overall, the results demonstrate that temperature is a key operational parameter governing acidogenic performance and carbon transformation pathway. The simple and novel proposed kinetic model provides a useful tool for predicting VFA production and optimizing anaerobic pretreatment strategies aimed at enhancing downstream nutrient removal processes. Optimizing SBR operation for nutrient removal also offers sustainability benefits by improving resource efficiency and reducing energy and chemical inputs. Full article

Microplastic pollution is increasingly serious worldwide, threatening human and animal health. The cow rumen is a key organ for nutrient digestion and absorption, and its fermentation is closely related to rumen microorganisms. Here, we investigated how polystyrene microplastics (PS-MPs) with varying particle sizes and concentrations affect rumen fermentation and the biodegradability of PS-MPs by rumen fermentation. The results reveal that exposure to PS-MPs lowered gas production and gas concentrations, as well as volatile fatty acid content, and these decreases were positively correlated with PS-MP concentration. However, higher PS-MP concentration and larger particle size increased the activity of carboxymethyl cellulose, β-glucosidase, and xylanase. Furthermore, PS-MP exposure reduced the abundance of certain rumen microorganisms and altered metabolic pathways and metabolites linked to PS-MP biodegradation. It was also found that PS-MP content decreased significantly after 24 h fermentation. Therefore, PS-MPs can inhibit rumen fermentation by affecting the rumen microbiome, and rumen microorganisms and their secreted enzymes can biodegrade PS-MPs to produce styrene and derivatives; such small molecules may further disrupt rumen homeostasis, thereby affecting lactation performance. In addition, rumen microbial degradation of PS-MPs provides a new idea to resolve future microplastic contamination challenges. Full article

Bioethanol is an alternative energy source to fossil fuels and can serve as a raw material for the production of sustainable aviation fuel. Poly(3-hydroxybutyrate) (PHB) is a biodegradable plastic with the potential to replace petrochemical plastics. Lignocellulose has a renewable and eco-friendly nature, and it is a key factor in determining the environmental impact of bioethanol and PHB. In this study, we addressed this issue by developing Escherichia coli for the co-production of bioethanol and PHB from rice straw hydrolysate (RSH). Metabolic evolution was employed to enhance ethanol tolerance in the ethanologenic E. coli strain. To mitigate the toxicity of RSH, the strain was modified by rewiring the pentose phosphate pathway and subsequently subjected to metabolic evolution. The strain was further reshaped by reprogramming xylose metabolism and recruiting the PHB synthesis pathway. As a result, the engineered strain simultaneously utilized glucose and xylose while producing 19.8 g/L of bioethanol and 3.5 g/L of PHB in 30 h. The bioethanol yield and the PHB content account for 0.40 g/g and 38% of dry cell weight, respectively. Overall, it indicates the potential application of this developed strain in lignocellulosic biorefineries. Full article

PET biodegradation remains limited due to its intrinsic properties—high crystallinity, hydrophobicity, and strong chemical stability. These characteristics lead to extremely slow degradation rates and contribute to PET’s persistence in the environment. Understanding how microorganisms respond at the molecular level when exposed to such a recalcitrant polymer is therefore essential. Living organisms express genes in response to their needs during development. When microbes are under critical conditions, such as when contaminants are present, they express genes encoding specific enzymes that attack the pollutant. In this study, a fungus isolated from the infected fruit of the plant Randia monantha was identified as Aspergillus terreus. It was tested for polyethylene terephthalate (PET) degradation, and the fungus Aspergillus nidulans was evaluated due to its previously reported recombinant cutinases for PET degradation. A microplastic polyethylene terephthalate (PET-MP) particle size of <355 μm for degradation was established, and a PET weight loss of 1.62% for A. nidulans and 1.01% for A. terreus was found. Additionally, the degradation of PET was confirmed by FTIR and SEM. This study also compares the transcriptomic profiles of Aspergillus nidulans and Aspergillus terreus during cultivation with PET-MP residues, which serve as a replacement for the carbon source. We present the first evidence of chitinase overexpression during direct exposure of PET to Aspergillus fungi. Interestingly, chitinase expression was detected in the crude extracts of A. nidulans and A. terreus during culture in the presence of PET residues, which replaced the carbon source. The chitinase produced by each fungus has a similar molecular weight of approximately 44 kDa. Chitinase activity was monitored over a 14-day cultivation period; from day 2, chitinase activity was detected in both cultures and continued to increase until day 14, when the highest values reported in this work were 24.88 ± 4.17 U mg⁻¹ and 10.41 ± 0.47 U mg⁻¹ for A. nidulans and A. terreus, respectively. Finally, we proposed a pathway for PET degradation by Aspergillus fungi that involves mycelial adherence and the secretion of hydrophobins, followed by the production of intermediates and monomers via esterase hydrolysis, and ultimately, the entry of monomers to the ethylene glycol (EG) and terephthalic acid (TPA) pathways, further suggesting these Aspergillus as candidates to produce valuable compounds under these conditions, such as muconic acid, gallic acid, and vanillic acid. Full article

The proliferation of single-use petroleum-based foams in protective packaging has become a major source of persistent plastic waste, posing significant challenges to environmental sustainability. To address this issue, we developed a fully biodegradable cushioning foam from bamboo, a rapidly renewable biomass, using an environmentally benign deep eutectic solvent (DES) process that avoids harsh chemical bleaching. The resulting lignin-containing cellulose nanofibril (LCNF)/sodium alginate (SA) foam exhibits low density (0.23 g/cm³), high compressive strength (0.24 MPa at 70% strain), and excellent elasticity (90% recovery at 50% strain), enabled by a dual-network structure of Ca²⁺-crosslinked SA and entangled LCNFs. Critically, the material is fully compostable and leaves no microplastic residues, offering a circular end-of-life pathway. In real-world banana drop tests, it matched the performance of commercial expanded polyethylene (EPE) while outperforming polyethylene bubble wrap. This work demonstrates a practical, scalable route to replace fossil-derived cushioning materials with a bio-based alternative that aligns with the principles of cleaner production and circular economy. Full article