A cradle-to-grave life cycle assessment of multilayer plastic film food packaging materials, comparing to a paper-based alternative

This study evaluates alternatives to polymers with high environmental impact in plastic-based multilayer packaging (PMP). This Life Cycle Assessment (LCA) quantifies energy demand, fossil resource scarcity (FRS), and greenhouse gases (GHG) associated with 14 PMP films, with comparisons to coated paper-based packaging (CPP). Two functional units, one ton and one m3of packaging, were considered. End-of-life scenarios, including landfilling and incineration, were based on average US use for plastic waste, along with recycling for CPP paper. Production of polyamide 6 (PA 6) has four times the GHG impact of polymers like high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) due to its natural gas demand, and almost twice that of polystyrene (PS), the second highest environmental burden for a skin layer on a volume basis. Polyethylene terephthalate (PET) is a promising alternative to PA 6, offering improved functionality and reduced environmental impact. As a core layer, ethylene vinyl alcohol (EVOH) has lower impacts than PA 6 in terms of energy (-35%), GHGs (-74%), and FRS (-34%). Among PMPs, HDPE-EVOH, LDPE-EVOH, LLDPE-EVOH, and PP-EVOH have lower environmental impacts while meeting required O2and water permeability. CPP production is more environmentally-friendly than PMPs in energy (25-34% improvement), FRS (81-83% improvement), and GHGs (34-62% improvement). Using 75% recovered paper in CPP production improves energy, FRS, and GHG impacts by up to 41%, 16%, and 11%, respectively, compared to using virgin paper. This study offers a framework for layered packaging impact assessments, guiding manufacturers toward environmentally-friendly options that retain essential functions.

Biodegradation assessment tests of biopolymers in standardised water: different sources of variability

This study assessed the ultimate biodegradation degree of two resins, polyhydroxybutyrate and polylactic acid (PHB and PLA), and three commercial biobased bags (BMAT, BGREEN, and BBEIGE) through the measurement of oxygen consumption in closed respirometers. Activated sludge from a wastewater treatment plant (WWTP) was used as the inoculum, cellulose was used as the reference material, and five trials were conducted with two different devices under identical conditions, with a 28-day incubation period. The results revealed statistically significant differences in the biochemical oxygen demand (BOD) measurements for cellulose, PHB, and PLA between the two devices and within the same devices across different trials. The degree of biodegradation (Dt), calculated as the percentage of theoretical oxygen demand (ThOD), varied depending on the device and trial. For cellulose, Dt ranged from 61 to 93%; for PLA, the maximum Dt was 6%; and for PHB, Dt oscillated between 16 and 72%. These findings highlight the critical importance of carefully selecting the testing equipment, as it significantly influences biodegradation results, in addition to the already known interlaboratory variability caused by the inoculum.

Microplastics reduced the natural attenuation of antibiotic resistance genes in fertilized soils

The prolonged application of mulch and manure in agriculture has led to significant microplastic (MP) pollution in fertilized soils, raising global concerns about its potential impacts on soil health and ecosystem function. However, the effects of MP exposure on antibiotic resistance genes (ARGs) and microbial communities in fertilized soils are unknown. Therefore, we comprehensively explored the trends and drivers of ARGs during their natural abatement under the stress of conventional and biodegradable MP addition in fertilized soils using a soil microcosm experiment and metagenomic. The findings indicated that the presence of polybutylene succinate MPs (PBS-MPs) reduced the natural attenuation rate of ARGs in fertilized soils while increasing the fraction of high-risk ARGs in soils. Microbial communities and mobile genetic elements (MGEs) mainly drove the inhibitory effect of MPs on ARG abatement. Interestingly, most potential hosts for the coexistence of ARGs, metal resistance genes (MRGs), and MGEs were annotated as pathogens, such as Escherichia spp., Salmonella spp., and Klebsiella spp. In addition, MP stress in fertilized soil may lead to long-term contamination by highly virulent and antibiotic-resistant Escherichia coli. MPs influence the distribution of carbon sources, which in turn reduces the diversity and stability of soil microbial communities, while simultaneously promoting the colonization of crucial ARG hosts, like Dyella spp. This ultimately prolonged the high-risk state for ARG proliferation in the soil. This study highlights the significant risk posed by MPs to the persistence and spread of ARGs in fertilized soils. These results provide valuable insights for managing MP contamination in agricultural systems, emphasizing the need for sustainable practices to mitigate the long-term environmental risks associated with MP pollution.

Bioinspired single-atom nanozymes for microplastic degradation

Copper single-atom-loaded graphitic nitride nanozymes (Cu SAs) were constructed by bioinspired rational design from natural laccase and density functional theory calculations. Theoretical investigation revealed the geometrical and electronic structural advantages of the Cu-N active center. Experimental tests confirmed the excellent performance in microplastic degradation, with more than 90% mineralized into non-toxic products, providing a new strategy for microplastic pollution management.

Naturally occurring eugenyl acetate as biobased plasticizer for sustainable polylactide formulations with improved toughness

In this study, we explore the potential of eugenyl acetate (EAc), a naturally occurring ester of eugenol, as a biobased plasticizer to overcome the intrinsic brittleness of polylactide (PLA) derived from starch. A theoretical assessment of the miscibility between PLA and EAc is carried out. Our findings demonstrate that EAc shows exceptional miscibility with PLA, as confirmed by their similar solubility parameters (EAc-19.83 MPa1/2, and PLA-20.66 MPa1/2), and an interaction parameter of χ = 0.39. The incorporation of EAc improves the ductility of PLA, with strain at break increasing to 427.7 % at 20 wt% EAc, compared to a brittle 10.2 % for neat PLA. The plasticizing effect of EAc also leads to a considerable reduction in the glass transition temperature of PLA, from 60.4 °C to 35.7 °C at 20 wt% EAc. Scanning electron microscopy reveals no phase separation and the development of plastic deformation in PLA formulations with 15-20 wt% EAc. Additionally, all plasticized formulations exhibit full biodegradation in controlled compost conditions in <8 weeks. These results contribute to advancing PLA-based formulations that are both high-performance and eco-friendly, supporting the broader goals of sustainable development in polymer science.

Investigating aquatic biodegradation and changes in the properties of pristine and UV-irradiated microplastics from conventional and biodegradable agricultural plastics

There is an increasing tendency to replace conventional agricultural plastic mulching films with biodegradable alternatives. However, while the latter biodegrade well under controlled conditions (e.g. industrial compost), their biodegradation in non-target environments (e.g. aquatic environments) is questioned and poorly understood. Therefore, in this study, microplastics derived from conventional polyethylene (PE) and biodegradable polybutylene adipate terephthalate starch blend (PBAT) mulching films were exposed to UV irradiation and subsequently tested for their ready biodegradability in an aqueous medium where changes in their characteristics were evaluated. The results showed limited biodegradation for pristine and UV-aged PE: no morphological, surface chemical or internal changes were observed. Pristine PBAT showed signs of initial biodegradation, while UV-aged PBAT biodegraded by up to 57%. New functional groups appeared on the PBAT surface after UV irradiation according to FTIR analysis and crystallinity increased after biodegradation. Elemental analysis revealed a range of metals in PE and PBAT microplastics. No changes in metal distribution analysed in microplastic after UV-aging or biodegradation were found, except that less titanium was present in PBAT after biodegradation indicating potential leaching. None of the PBAT microplastics had ecotoxic effects towards the aquatic plant Lemna minor. Pristine and UV-aged PE showed negative effects on roots, but these were not observed after biodegradation. Low biodegradation of pristine PBAT and possible leaching of metals demonstrated here raise questions about the sustainable use of biodegradable alternatives, especially when they enter non-target environments.

A bibliometric review of waste management and innovation: Unveiling trends, knowledge structure and emerging research fronts

The pressing challenges in waste management have motivated this comprehensive study examining prior research and contemporary trends concerning innovation and waste management. A meticulous investigation of 2264 documents (1968-2024) was conducted using bibliometrix R-tool to analyse Scopus and Web of Science databases, offering a holistic global perspective. Heightened societal concern about waste management, driven by soaring waste production from consumption patterns, requires urgent exploration of effective waste elimination and transformation systems. This study provides a comprehensive summary of the topic, delving deeply into its complexities. Through thorough analysis of global trends, it constitutes a significant stride towards identifying effective solutions, offering valuable contributions to both scientific understanding and practical applications. This research pioneers a comprehensive synthesis of innovation and waste management issues, showcasing originality and substantial contributions. The identified collaborative networks expose a lack of transnational cooperation, potentially hindering waste management innovation. Future research around waste management innovation should focus on synergies among competitors within the same industry and across industries to minimize waste and maximize resource utilization, 4.0 technologies, global waste chain impacts and challenges along with solutions for developing countries.

Effects of biodegradable microplastics on soil microbial communities and activities: Insight from an ecological mesocosm experiment

Microplastics (MP) are being released into the environment at an increasing rate, causing extensive pollution in soils and affecting biota and processes. Although the use of biodegradable plastic has increased, its effects on the soil microbial community are not yet well understood. A controlled mesocosm experiment was conducted to investigate the response of soil microbial communities to increasing amounts of starch-polybutylene adipate terephthalate MPs (PBAT-BD-MPs) added to the soil. The experiment included microbes, earthworms, springtails, and plants. The PBAT-BD-MPs were added to the soil column at doses ranging from 0 to 0.8 % w/w of soil dry mass, and the columns were incubated for 11 weeks under controlled climatic conditions. Bacterial and fungal amplicon sequencing was used to investigate the dose-dependent response of the soil microbial communities' alpha and beta diversity. The alpha diversity indices of the bacterial and fungal communities increased with increasing PBAT-BD-MP concentration. Bacterial richness was highest at the highest MP concentration (0.8 %). A similar trend was observed in the fungal community, with a significant increase in fungal richness as PBAT-BD-MP concentration increased. The alpha diversity of both bacterial and fungal communities significantly increased in MP treatments compared to the control treatment. At the highest MP concentration (0.8 %), the abundance of the bacterial phylum Planctomycetes showed a significant increase, while Firmicutes showed a significant decrease. The abundance of the fungal phyla Ascomycota and Mortierellomycota also significantly increased at the highest PBAT-BD-MP concentration compared to the control group. Alongside changes in the soil microbial community, we observed a rise in soil respiration as the concentration of PBAT-BD-MPs increased. Our three-month mesocosm study demonstrates that the introduction of biodegradable microplastics into the natural standard soil environment in realistic concentrations (0-0.025-0.05-0.2-0.8 %) and particle size distribution alters the soil bacterial and fungal community.

Asymmetric Atomic Pt-B Dual-Site Catalyst for Efficient Photoreforming of Waste Polylactic Acid Plastics in Seawater

Waste plastic has imposed significant burdens on marine ecosystems. Converting plastic into high-value products via photocatalysis is an emerging and promising approach, but its low activity and product selectivity pose great challenges. Herein, we report a carbon nitride-anchored atomically dispersed Pt-B dual-site catalyst (Pt SA/BCN100) for the photoreforming of polylactic acid (PLA) into high-value chemicals and H2 in seawater. Experiments and DFT calculations reveal that significantly enhanced charge transfer occurs between the Pt site and the B site, and the hole-rich B site can selectively trigger the activation and cleavage of the C-H and C-C bonds of PLA to form acetic acid (AA), while the electron-rich Pt site drives the reduction of H protons to H2. As a result, Pt SA/BCN100 exhibits a high H2 evolution rate of 993 μmol gcatal-1 h-1 and an AA production rate of 300 μmol gcatal-1 h-1 with a selectivity of over 98%. We also demonstrate the direct photoreforming of g-scale real-world PLA wastes and low concentrations of PLA microplastics in natural seawater. Techno-economic analysis and environmental assessment show that this catalytic system can significantly reduce carbon emissions and has potential commercial value.

Recombination of agricultural residues into moldable composites

Increasing efforts have been devoted to developing biobased and biodegradable plastics and composites from lignocellulosic biomass. Current bioplastic production entails multiple challenging steps including monomer production from biomass as well as polymer synthesis and modification. Here, we report a practical recombination strategy to transform agricultural residues into moldable cellulose-reinforced lignin (CRL) composites. The strategy involves deconstruction of biomass particles followed by thermo-compression molding of cellulose fibers and lignin mixtures. The resulting CRL composites demonstrated excellent mechanical and thermal properties as well as water, abrasive, and flame resistance. Mechanistic studies reveal that small particle size, removal of water-soluble fractions, as well as reservation of lignin and its cross-linking reactivity have considerably positive effects on preparation of high-quality composite items. These insights offer a versatile strategy for transforming various types of low-grade biomass, such as corn stover, into eco-friendly and potentially biodegradable or compostable composites that can serve as sustainable alternatives to traditional duroplast materials.

Enhancing the compatibility and performance of poly (lactic acid) and thermoplastic polyolefin elastomer blends through a dual compatibilization strategy

Application of biodegradable polylactic acid (PLA) is limited by its poor toughness. This research focuses on modifying PLA using thermoplastic elastomers (TPO), primarily due to their dual advantages of enhancing performance and reducing application costs. Two thermoplastic polyolefin elastomers (TPO) (NS06, Versify2300) were blended to prepare a superior elastomer TPO(NV) (NS06:Versify2300 = 80:20). This improved TPO(NV) was then used as a toughening agent to enhance the toughness of polylactic acid (PLA). To enhance the compatibility between PLA and TPO(NV), TPO(NV)-g-(GMA-co-St) graft copolymer and dibutyl itaconate (DBI) were introduced into the PLA/TPO(NV) blend system. The effects of different compatibilizers on the compatibility, crystallization behavior, rheological properties, mechanical properties, and microstructure of the PLA/TPO(NV) blends were systematically studied. The results indicated that glycidyl methacrylate (GMA) and styrene (St) were successfully grafted onto the TPO(NV) molecular chains. The epoxy groups in GMA within the graft copolymer could react with the end groups of the PLA resin, while the double bonds in DBI could react with the main chains of either PLA or TPO(NV) elastomer. This effectively connected the PLA and TPO(NV) molecular chains, collectively enhancing the compatibility between TPO(NV) elastomer and PLA. The non-isothermal crystallization ability of TPO(NV) decreased after blending with PLA, and this effect was further amplified with the introduction of the TPO(NV)-g-(GMA-co-St) graft copolymer or DBI. However, the plasticizing effect of DBI increased the mobility of the polymer molecular chains, thereby enhancing the crystallization ability. Therefore, when DBI was used alone to enhance the compatibility of PLA/TPO(NV) blends, the crystallinity of the blend did not change significantly. In contrast, when the TPO(NV)-g-(GMA-co-St) graft copolymer was used alone or in combination with DBI, the crystallinity of the blend decreased significantly. Mechanical property tests indicated that the addition of either the TPO(NV)-g-(GMA-co-St) graft copolymer or DBI improved the compatibility of PLA/TPO(NV) blends, thereby enhancing their mechanical properties. However, the combined addition of both the TPO(NV)-g-(GMA-co-St) graft copolymer and DBI resulted in a more pronounced effect. The notched impact strength and elongation at break reached optimal values, which were 1.9 times and 10.4 times those of the PLA/TPO(NV) blend, respectively. At this point, the fracture surface of the blend exhibited significant plastic flow, indicating characteristics of ductile fracture.

Tunable Mechanical Properties in Biodegradable Cellulosic Bioplastics Achieved via Ring-Opening Polymerization

The development of bioplastics is advancing globally to promote a sustainable society. In this study, we designed cellulosic dual-network bioplastics to address the need for sustainable materials with balanced mechanical properties and biodegradability. Cellulose was used as the first network, and the second network was functionalized to enhance mechanical strength while preserving biodegradability. The dynamic covalent moieties within the second network were generated through dithiolane ring-opening polymerization. The ultimate tensile strength and flexural elongation were controlled within 8.8-193 MPa and 3.3-32.5%, respectively, depending on the degree of dynamic bonds. Moreover, the bioplastics exhibited gradual biodegradability, achieving approximately 30% degradation within 2 weeks. Interestingly, our bioplastics demonstrated the ability to coexist with plants, as their degradation did not negatively affect cell viability or plant growth. This study provides a promising approach to developing advanced bioplastics that reach sustainability goals while offering tunable mechanical properties.

Lack of functional polyester-biodegrading potential in marine versus terrestrial environments evidenced by an innovative airbrushing technique

Biodegradable plastics, primarily aliphatic polyesters, degrade to varying extents in different environments. However, the absence of easily implementable techniques for screening microbial biodegradation potential -coupled with the limitations of non-functional omics analyses- has restricted comparative studies across diverse polymer types and ecosystems. In this study, we optimized a novel airbrushing method that facilitates functional analyses by simplifying the preparation of polyester-coated plates for biodegradation screening. By repurposing an airbrush kit, polyester microparticles (MPs) could be evenly sprayed onto solid media, enabling rapid detection of extracellular depolymerizing activity via clearing zone halos. This technique was effective in screening both isolated microbial cultures and natural environmental samples, demonstrating its versatility. The method was successfully applied across multiple environments, ranking the biodegradability of six polyesters, from most to least biodegradable: poly[(R)-3-hydroxybutyrate] (PHB), polycaprolactone (PCL), poly(ethylene succinate) (PES), poly(butylene succinate) (PBS), poly(lactic acid) (PLA), and poly(butylene adipate-co-terephthalate) (PBAT). Most notably, it revealed a consistent 1,000-fold higher biodegradation potential in terrestrial compared to marine environments. This approach offers a valuable tool for isolating novel polyester-degrading microbes with significant biotechnological potential, paving the way for improved plastic waste management solutions.

Biobased Polyesters with Ultrahigh UV Shielding and Water Degradation Derived from Multifunctional Tetracyclic Diesters

The development of biobased polyesters with the combination of high UV shielding and degradability is a significant challenge. Herein, three 4-membered cyclic monomers containing two pyrrolidone and two furan rings were prepared by the aza-Michael addition of biobased bifuran diamine and dimethyl itaconate (DMI). They were available in melt polycondensation reactions with various diols to synthesize biobased polyesters. The bifuran structure endowed the polyesters with ultrahigh UV-shielding cutoff values of up to 443 nm, which achieved the highest UV-shielding results among the commercial polyesters. The bipyrrolidone structure conferred high hydrolysis sensitivity to the polyesters, which facilitated hydrolytic degradation of the polyester in an aqueous environment. The variability of the link structure between the multirings of the three monomers can regulate the various properties of the polyesters. Overall, the 4-membered cyclic monomers are promising precursors for sustainable biobased materials in providing high UV shielding and hydrolysis sensitivity.

Chemical safety and risk assessment of bio-based and/or biodegradable polymers for food contact: A review

Bio-based and/or biodegradable polymers are being developed and applied as a sustainable and innovative alternative to conventional petroleum-based materials for food packaging applications. From the chemical standpoint, bio-based and/or biodegradable polymers present a complex chemical composition that includes additives, monomers, and other starting substances, but also, oligomers, impurities, degradation products, etc. All these compounds may migrate into the food and can be a hazard to the consumers' health. Thus, identifying potential migrants is crucial to assess the safety of these materials. The analytical methods applied to investigate migrants in bio-based and/or biodegradable polymers are reviewed and commented on. Mostly, gas chromatography or liquid chromatography coupled to mass spectrometry and specifically high-resolution mass spectrometry are the techniques of choice. In addition, a summary of recently published migration studies of chemicals from bio-based and/or biodegradable polymers into food simulants and food is provided. Moreover, current approaches to risk assessment of packaging materials are presented and illustrated with examples. Therefore, this review aims to highlight the chemical safety issues raised by biopolymers for food contact applications, that are often overlooked.

When plastisphere and drilosphere meet: Earthworms facilitate microbiome and nutrient turnover to accelerate biodegradation of agricultural plastic films

Agricultural plastic mulching films have been an environmental concern for decades. The effects of the interactions between the anthropogenic plastisphere and other soil biospheres, particularly that of earthworms, on the fate of plastics remain poorly understood. Here, we investigated the decomposition of buried nonbiodegradable low-density polyethylene (LDPE) versus biodegradable PBTA/PLA copolymers in the presence of earthworms (Amynthas cortices) in dynamic microcosms. Earthworms significantly enhanced the biodegradation of plastic films in situ, as confirmed by mass reduction, surface modification, and changes in the molecular weights of films. Notably, the PBTA/PLA films exhibited a 1.41-fold increase in mass loss and a 5.69% reduction in the number-average molecular weight when incubated with earthworms. Earthworms influenced the microbial assembly within the plastisphere by increasing both bacterial and fungal biodiversity, as well as their network complexity. The time-decay patterns in the abundance of keystone degrader taxa, including the genera Noviherbaspirillum, Rhizobacter, and Mortierella, were mitigated by earthworms over the 60-day period. Additionally, earthworms preferentially consumed recalcitrant dissolved organic matter in LDPE and PBAT/PLA plastisphere soils, thereby increasing the bioavailability of components that serve as nutrient supplies for plastisphere microbiomes. Our findings demonstrate that earthworms enhance the decomposition of plastics in soils via cross-species interplay within the plastisphere and drilosphere, contributing not only to soil conditioning and biodiversity but also to plastic biodegradation in natural agroecosystems.

Differentiating low-carbon waste management strategies for bio-based and biodegradable plastics under various energy decarbonization scenarios

Bio-based and biodegradable (bio-)plastics are heralded as a key solution to mitigate plastic pollution and reduce CO2 emissions. Yet, their end-of-life treatments embodies complex energy and material interactions, potentially leading to emissions through incineration or recycling. This study investigates the cradle-to-grave, emphasizing the waste management stage, carbon footprint for several types of bio-plastics, leveraging both GWP100a and CO2 uptake methods to explore the carbon reduction benefits of recycling over disposal. Our findings indicate that in scenarios characterized by carbon-intensive electricity, using polylactic acid (PLA) as an example, incineration with energy recovery (-1.6316 kg CO2-eq/kg, PLA) yields a more favorable carbon footprint compared to chemical recycling (-1.5317 kg CO2-eq/kg, PLA). In contrast, in environments with a high proportion of renewable energy, chemical recycling is a superior method, and compared to incineration (-1.4087 kg CO2-eq/kg, PLA), the carbon footprint of chemical recycling (-2.0406 kg CO2-eq/kg, PLA) are significantly reduced. While mechanical recycling presents considerable environmental benefits, its applicability is constrained by the waste quality, especially in the case of biodegradable plastics like PLA. In addition, the degradation of biodegradable plastics such as PLA was modeled during compost and anaerobic digestion processes. This enables us to quantify the specific biogenic carbon emissions released during these processing steps, revealing the direct emissions with dynamic degradation. This study highlights the importance of tailoring bio-plastic waste management strategies to support global energy decarbonization while understanding their life-cycle carbon metabolism to effectively tackle plastic pollution and climate change.

Mineralizing Biofilm towards Sustainable Conversion of Plastic Wastes to Hydrogen

The integration of inorganic materials with biological machinery to convert plastics into fuels offers a promising strategy to alleviate environmental pollution and energy crisis. Herein, we develop a type of hybrid living material via biomineralization of CdS onto Shewanella oneidensis-based biofilm, which is capable of sustainable hydrogen production from poly(lactic acid) (PLA) wastes under daylight. We reveal that the formed biofilm microstructure provides an independent anaerobic microenvironment that simultaneously supports cellular viability, maintains hydrogenase activity, and preserves the functional stability of CdS, giving rise to the efficient plastic-to-hydrogen conversion efficiency as high as 3751 μmol H2 g-1 PLA. Besides, by genetically engineering transmembrane pili conduit and incorporating conductive nanomaterials to strengthen the electron transfer across cellular interface and biofilm matrices, we show that the conversion efficiency is further enhanced to 5862 μmol H2 g-1 PLA. Significantly, we exhibit that a long-term sustainable plastic-to-hydrogen conversion of 63 d could be achieved by periodically replenishing PLA wastes. Overall, by the synergistic integration of biotic-abiotic characteristics the developed biofilm-based biomineralized hybrid living material is anticipated to provide a new platform toward the efficient conversion of plastic wastes into valuable fuels, and bridge the gap between environmental contamination and green energy production.

Insect farming: A bioeconomy-based opportunity to revalorize plastic wastes

Managing plastic waste is one of the greatest challenges humanity faces in the coming years. Current strategies-landfilling, incineration, and recycling-remain insufficient or pose significant environmental concerns, failing to address the growing volume of plastic residues discharged into the environment. Recently, increasing attention has focused on the potential of certain insect larvae species to chew, consume, and partially biodegrade synthetic polymers such as polystyrene and polyethylene, offering novel biotechnological opportunities for plastic waste management. However, insect-assisted plastic depolymerization is incomplete, leaving significant amounts of microplastics in the frass (or manure), limiting its use as a soil amendment. In this perspective, we propose a novel two-step bioconversion system to overcome these limitations, using insects to sustainably manage plastic waste while revalorizing its by-products (frass). The first step involves pyrolyzing microplastic-containing frass from mealworms (Tenebrio molitor larvae) fed on plastic-rich diets to produce biochar with enhanced adsorptive properties. The second stage integrates this biochar into the entomocomposting of organic residues, such as food waste, using black soldier fly (Hermetia illucens) larvae to produce nutrient-rich substrates enriched with carbon and nitrogen. This integrated system offers a potential framework for large-scale industrial applications, contributing to the bioeconomy by addressing both plastic waste and organic residue management. We critically examine the advantages and limitations of the proposed system based on current literature on biochar technology and entomocomposting. Key challenges and research opportunities are identified, particularly concerning the physiological and toxicological processes involved, to guide future efforts aimed at ensuring the scalability and sustainability of this innovative approach.

A Critical Review of an Environmental Risk Substance Induced by Aging Microplastics: Insights into Environmentally Persistent Free Radicals

Microplastics (MPs), as an emerging contaminants category, can undergo complex aging in a variety of environmental matrices in which the chemical bonds of polymer molecules can be broken to form free radicals. While the existence of free radicals in aged plastics has been known for over half a century, only recently has significant research on a new type of environmentally risky substance, namely environmentally persistent free radicals (EPFRs), present in aged MPs and their environmental effects, been started, but it is still in its infancy. To address these issues, this work examines EPFR generation on MPs and their environmental effect by reviewing publications from 2012 to 2023. The aging processes and mechanisms of MPs in the environment are first summarized. Then, the occurrence and formation mechanisms of EPFRs on aged MPs are specifically discussed. Additionally, the reactivity of EPFRs on aging MPs and their influencing factors are comprehensively considered, such as their physicochemical properties, oxygen content, and coexisting substances. Due to their reactivity, EPFRs can interact directly with some substances (e.g., p-nitrophenol and proteins, etc.) or induce the generation of reactive oxygen species, leading to diverse environmental effects, including pollutant transformation, biotoxicity, and health risks. Finally, research challenges and perspectives for EPFRs formation on aging MPs and related environmental implications are presented. Given the environmental fate and risk of MPs-EPFRs, our urgent call for a better understanding of the potential hazards of aged MPs is to help develop a sustainable path for plastics management.

Machine Learning-Assisted "Shrink-Restricted" SERS Strategy for Classification of Environmental Nanoplastic-Induced Cell Death

The biotoxicity of nanoplastics (NPs), especially from environmental sources, and "NPs carrier effect" are in the early stages of research. This study presents a machine learning-assisted "shrink-restricted" SERS strategy (SRSS) to monitor molecular changes in the cellular secretome exposure to six types of NPs. Utilizing three-dimensional (3D) Ag@hydrogel-based SRSS, active targeting of molecules within adjustable nanogaps was achieved to track information. Machine learning was employed to analyze the overall spectral profiles, biochemical signatures, and time-dependent changes. Results indicate that environmentally derived NPs exhibited higher toxicity to BEAS-2B and L02 cells. Notably, the "NPs carrier effect," resulting from pollutant adsorption, proved to be more harmful. This effect altered the death pathway of BEAS-2B cells from a combination of apoptosis and ferroptosis to primarily ferroptosis. Furthermore, L02 cells demonstrated greater metabolic vulnerability to NPs exposure than that of BEAS-2B cells, especially concerning the "NPs carrier effect." Traditional detection methods for cell death often rely on end point assays, which limit temporal resolution and focus on single or multiple markers. In contrast, our study pioneers a machine learning-assisted SERS approach for monitoring overall metabolic levels post-NPs exposure at both cellular and molecular levels. This endeavor has significantly advanced our understanding of the risks associated with plastic pollution.

Ecodesign Enhancement of Polymeric Resins: Reinforcing with Synthetic and Natural Fibers Using Theory of Inventive Problem Solving-Algorithm of Inventive Problem Solving for Sustainable Composite Design

This study examines the enhancement of the mechanical strength of polymer resins through reinforcement with synthetic (glass) and natural (hemp, jute) fibers, using the TRIZ-ARIZ methodology to optimize composite design for improved mechanical properties, sustainability, and economic efficiency. Mechanical testing, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were conducted to evaluate the properties of the composite materials. Regarding tensile strength testing, the results showed the following: jute fiber achieved the best results, with a maximum tensile values of 43.75 MPa (partial reinforcement) and 43.53 MPa (complete reinforcement); glass fiber recorded maximum tensile values of 34.55 MPa (partial reinforcement) and 34.52 MPa (complete reinforcement); and hemp fiber yielded maximum tensile values of 24.98 MPa (partial reinforcement) and 24.86 MPa (complete reinforcement). The mechanical performance of partial reinforcements (in the area of maximum stress) was similar to that of complete reinforcements, enabling a reduction in material usage by up to 60%. The thermal analysis (TGA) results demonstrated that glass fiber-reinforced composites exhibit high thermal stability, with mass loss starting at 320 °C and a residual mass of 8.02%; for other composite materials, thermal degradation begins at 305 °C, with a residual mass of 3.69%; in jute fiber-reinforced composites, thermal degradation starts at 300 °C, with a residual mass of 3.71%. SEM analysis generally revealed good fiber-matrix adhesion, while defects such as voids or detached fibers contributed to reduced mechanical strength. These results demonstrate that natural fiber-reinforced composite materials, particularly those reinforced with jute, can be used in sustainable engineering applications. They also show that localized reinforcement provides high performance with minimal resource consumption.

Novel insights into photoaging mechanisms and environmental persistence risks of polylactic acid (PLA) microplastics: Direct and indirect photolysis

Polylactic acid (PLA), as a biodegradable plastic, exhibits high sensitivity to ultraviolet (UV) radiation, yet the mechanisms and environmental risks of its photoaging remain unclear. This study uses quantum chemical calculations (DFT and TD-DFT) and kinetic simulations to explore the direct and indirect photoaging of PLA. Direct photoaging indicates that the highest oscillator intensity absorption peaks occurred at 172 and 246 nm, corresponding to the 13th singlet (S13) and 48th triplet (T48) states, thereby initiating the Norrish I and Norrish II mechanisms. The innovative "electron-hole" technology effectively clarifies the variations in photoaging mechanisms under different wavelengths. Indirect photoaging involves multiple reactive oxygen species (ROS) like •OH, 1O2, •O2-, and •HO2. The study confirms the anhydride production hypothesis and proposes two novel •OH-induced mechanisms: carbonyl carbon addition and branched methyl hydrogen dehydrogenation. Both mechanisms are thermodynamically advantageous, but their products pose potential environmental risks. ROS species and concentrations impact both PLA's photoaging mechanisms and environmental persistence. Low •OH concentration in northeast China, especially in winter, suggests a significant photoaging risk. This study offers pioneering insights into photoaging mechanisms and emphasizes the pivotal role of ROS, offering recommendations for managing PLA environmental impacts and fates in China.

Smart conducting polymer innovations for sustainable and safe food packaging technologies

Biofilm formation on food packaging surfaces is a major issue in the industry, as it leads to contamination, reduces shelf life, and poses risks to human health. To mitigate these effects, developing smart coatings that can actively sense and combat microbial growth has become a critical research focus. This study is motivated by the need for intelligent packaging solutions that integrate antimicrobial agents and sensors for real-time contamination detection. It is hypothesized that combining conducting polymers (CPs) with nanomaterials can enhance antimicrobial efficacy while maintaining the mechanical integrity and environmental stability required for food packaging applications. Through the application of numerous technologies like surface modification, CP-nanoparticle integration, and multilayered coating, the antimicrobial performance and sensor capabilities of these materials were analyzed. Case studies showed a 90% inhibition of bacterial growth and a tenfold decrease in viable bacterial counts with AgNPs incorporation, extending strawberries' shelf life by 40% and maintaining fish freshness for an additional 5 days. Moreover, multilayered CP coatings in complex systems have been shown to reduce oxidative spoilage in nuts and dried fruits by up to 85%, while maintaining the quality of leafy greens for up to 3 weeks under suboptimal conditions. Environmental assessments indicated a 30% reduction in carbon footprint when CP coatings were combined with biodegradable polymers, contributing to a more transparent and reliable food supply chain. CP-based films integrated with intelligent sensors exhibit high sensitivity, detecting ammonia concentrations below 500 ppb, and offer significant selectivity for sensing hazardous gases. These findings indicate that CP-based smart coatings markedly enhance food safety and sustainability in packaging applications.

Dynamic imine crosslinking for waterproof starch plastic with tunable mechanical properties

Starch-based plastics offer a potential solution to environmental pollution and can reduce the dependence on petroleum-based plastics. However, effectively preparing starch-based plastics with moisture resistance and high strength remains challenging. Herein, dialdehyde starch (DAS) with different degrees of oxidation was first synthesised. The molecular weight and crystallinity of DAS decreased depending on the aldehyde content, as determined through scanning electron microscopy, X-ray diffraction and molecular weight analyses. Subsequently, a sustainable starch plastic (DAS-DA) was prepared via the dynamic imine crosslinking of DAS with diamines. The influence of the degree of oxidation of DAS on the structure and properties of DAS-DA was systematically investigated. No linear relationship was observed between the tensile strength of DAS-DA and the aldehyde content of DAS. When the aldehyde content was 41.1 %, the resulting DAS41-DA exhibited optimal mechanical strength (27.8 MPa), exceeding that of most reported starch-based plastics. In addition, owing to the presence of imine crosslinking networks, DAS41-DA exhibited excellent water and solvent resistance (>60 days), good thermal stability (456 °C-462 °C) and excellent reprocessability and biodegradability. These findings provide a theoretical basis for the preparation of high-performance bioplastics from aldehyde-containing polysaccharides.

Distinct species turnover patterns shaped the richness of antibiotic resistance genes on eight different microplastic polymers

Elucidating the formation mechanism of plastisphere antibiotic resistance genes (ARGs) on different polymers is necessary to understand the ecological risks of plastisphere ARGs. Here, we explored the turnover and assembly mechanism of plastisphere ARGs on 8 different microplastic polymers (4 biodegradable (bMPs) and 4 non-biodegradable microplastics (nMPs)) by metagenomic sequencing. Our study revealed the presence of 479 ARGs with abundance ranging from 41.37 to 58.17 copies/16S rRNA gene in all plastispheres. These ARGs were predominantly multidrug resistance genes. The richness of plastisphere ARGs on different polymers had a significant correlation with the contribution of species turnover to plastisphere ARGs β diversity. Furthermore, polymer type was the most critical factor affecting the composition of plastisphere ARGs. More opportunistic pathogens carrying diverse ARGs on BMPs (PBAT, PBS, and PHA) with higher horizontal gene transfer potential may further magnify the ecological risks and human health threats. For example, the opportunistic pathogens Riemerella anatipestifer, Vibrio campbellii, and Vibrio cholerae are closely related to human production and life, which were the important potential hosts of many plastisphere ARGs and mobile genetic elements on BMPs. Thus, we emphasize the urgency of developing the formation mechanism of plastisphere ARGs and the necessity of controlling BMPs and ARG pollution, especially BMPs, with ever-increasing usage in daily life.

Deep eutectic solvent (DES) pretreatment and lignin regeneration for the development of a bamboo leaf-based bioplastic

The excessive utilization of petroleum-based plastic products has led to a pervasive environmental and human health threat. In response, the adoption of bioplastics derived from biomass has emerged as the foremost alternative to conventional plastics, owing to their inherent biodegradability and sustainability. The present study demonstrates the preparation of a biodegradable and cost-effective lignocellulosic bioplastic by utilizing dissolving bamboo leaf powder with deep eutectic solvents (DES) and regenerating lignin in situ. The DES was synthesized through a one-step heating and stirring method using choline chloride (ChCl) and anhydrous oxalic acid. The crystallinity of the bioplastics is enhanced by DES pretreatment, thereby improving the internal structural order of the material. Moreover, lignin regeneration reduces the pore size within the bioplastics and contributes to a more compact internal structure. The prepared lignocellulosic bioplastics exhibit remarkable mechanical strength, with a tensile strength of 113 MPa. Additionally, they demonstrate good water stability, as evidenced by a contact angle of 55.52°. Moreover, these bioplastics possess an exceptional biodegradability with a degradation rate exceeding 98% after 60 days. This study presents an innovative approach for the high-value utilization of bamboo leaf resources.

Facing the solid waste of cotton straw and plastic mulch film mixture in China: Centralized or decentralized pyrolysis facility?

The widespread use of plastic mulch film (PMF) has led to significant environmental pollution, with PMF residues dispersed and mixed with straw and soil, posing challenges for recycling. Here, we proposed the mobile pyrolysis facility for the cotton straw and mulch film mixture (CMM) to mitigate the collection, storage, and transportation costs, while the application of co-pyrolysis technology for CMM conversion could improve the added value of products. Additionally, centralized combustion power generation and centralized pyrolysis systems were also established to evaluate and compare their sustainability from economic and environmental perspectives. Results showed that mobile pyrolysis has better economic performance than the centralized scenarios, due to its high internal rate of return (31 %) and significant net present value (29.21 M USD). Meanwhile, the mobile pyrolysis facility achieved a GWP of -1.298 kgCO2-eq/kg, reducing emissions by 70.79 % and 38.82 % compared to the two centralized scenarios. In conclusion, mobile pyrolysis technology provides a promising solution for PMF residue recycling because of its economically competitive approach with a lower carbon footprint.

Challenges and opportunities in managing biodegradable plastic waste: A review

Biodegradable plastics have certain challenges in a waste management perspective. The existing literature reviews fail to provide a consolidated overview of different process steps of biodegradable plastic waste management and to discuss the support provided by the existing legislation for the same. The present review provides a holistic overview of these process steps and a comprehensive relative summary of 13 existing European Union (EU) laws related to waste management and circular economy, and national legislations plus source separation guidelines of 13 countries, to ensure the optimal use of resources in the future. Following were the major findings: (i) numerous types and low volumes of biodegradable plastics pose a challenge to developing cost-effective waste management infrastructure; (ii) biodegradable plastics are promoted as food-waste collection aids, but consumers are often confused about their proper disposal and are prone to greenwashing from manufacturers; (iii) industry-level studies demonstrating mechanical recycling on a full scale are unavailable; (iv) the existing EU legislation dealt with general topics related to biodegradable plastics; however, only the new proposal on plastic packaging waste and the EU policy framework for bioplastics clearly mentioned their disposal and (v) clear disparities were observed between disposal methods suggested by national legislation and available source separation guidelines. Thus, to appropriately manage biodegradable plastic waste, it is necessary to develop waste processing and material utilization infrastructure as well as create consumer awareness. In the end, recommendations were provided for improved biodegradable plastic waste management from the perspective of systemic challenges identified from the literature review.

Influence of the Molecular Weight of the Polycarbonate Polyol on the Intrinsic Self-Healing at 20 °C of Polyurethanes

Different polyurethanes (PUs) were synthesized with polycarbonate polyols of molecular weights of 500, 1000, and 2000 Da. Their self-healing abilities at 20 °C were tested, and their structural, thermal, and mechanical properties were analyzed. The PUs made with polycarbonates of molecular weights 500 (YC500) and 1000 Da (YC1000) exhibited self-healing at 20 °C, and the self-healing time of YC1000 was the shortest. The absence of crystallinity and the low degree of micro-phase separation favored self-healing at 20 °C in YC500. However, the presence of tack and the existence of allophanate species and urethane-carbonate and urea-carbonate hydrogen bonds disfavored self-healing. Consequently, the self-healing time at 20 °C of YC500 was longer than expected. On the other hand, YC1000 exhibited an "equilibrium" between urethane-carbonate and urea-carbonate hydrogen bonds and carbonate-carbonate interactions among the soft segments, so a particular structural order was produced that was associated with its fastest self-healing at 20 °C. The PU made with the polycarbonate of molecular weight 2000 Da did not exhibit self-healing at 20 °C because of its significant micro-phase separation, the presence of semi-crystalline soft domains, and the lower density of hydrogen bonds.

Open- and Closed-Loop Recycling: Highly Active Zinc Bisguanidine Polymerization Catalyst for the Depolymerization of Polyesters

In this study, the aliphatic N,N-bisguanidine zinc complex [Zn(DMEG2ch)2](OTf)2 ⋅ THF is introduced as a promising candidate for the chemical recycling of (bio) polyesters. This catalyst is highly active in the ring-opening polymerization (ROP) of lactide (LA) and ϵ-caprolactone (CL). The combination of polymerization and depolymerization activity creates new pathways towards a sustainable circular economy. The catalytic activity of [Zn(DMEG2ch)2](OTf)2 ⋅ THF for the chemical recycling of polylactide (PLA) via alcoholysis was investigated by detailed kinetic and thermodynamic studies. It is shown that various high value-added alkyl lactates can be obtained efficiently under mild reaction conditions. Catalyst recycling was successfully tested using ethanol for the degradation of PLA. In addition, LA can be recovered directly from PLA, enabling either open- or closed-loop recycling. Selective PLA degradation from mixtures with polyethylene terephthalate (PET) and polymer blends are presented. For the first time, a cascade recycling reaction of a PLA/polycaprolactone (PCL) blend is tested with a zinc-based bisguanidine catalyst, whereby PLA is degraded selectively at first and subsequent modification of the reaction conditions leads to efficient degradation of the remaining PCL. The highly active, universally applicable benign zinc catalyst allows the implementation of a circular plastics economy and thus the reduction of plastic pollution in the environment.

Bioplastics: No solution to healthcare's plastic pollution problem

As Canadian policy-makers recognize the urgency for concerted actions to reduce plastics (e.g., Canada's involvement in the international plastics treaty negotiations, zero plastic waste strategy, and single-use plastics regulations), the healthcare sector must also consider a more sustainable plastics system. In this context, the potential for novel bioplastics to mitigate healthcare's substantial plastic waste problem must be carefully interrogated. Our analysis examines the complexities of bioplastics, highlighting the technical challenges of identifying legitimate sustainable alternatives, and the practical barriers for implementing bioplastics as substitutes for consumable plastics in healthcare. We focus on the Canadian healthcare sector and regulatory landscape with the insights gained being applicable to other sectors and countries. Given the limitations identified, the focus on reducing consumption should remain the priority.

Advanced chemometric methodologies on single shot hyphenated LIBS data for rapid and reliable characterization of plastic classes

BACKGROUND

Plastic Solid Waste (PSW) sorting is a procedure of paramount importance in the mechanical recycling process of plastics waste. The major limitation of the techniques relying on physical properties of plastics is the time taken for analysis and poor accuracy. Spectroscopy has been shown to be a suitable method in plastic sorting due to its atomic and molecular characterization capabilities, and ability to give results in very short time scales. However, for practical applications it is essential to translate this technique into an automatic technology, by combining it with advanced chemometric tools which can give observer independent judgement.

RESULTS

The indigenously developed bi-model Laser Induced Breakdown Spectroscopy (LIBS)-Raman system with single source and single detector can record the LIBS-Raman spectral signals in single-shot mode in a total time frame of 20 ms. Out of the combinations of Principal Component Analysis (PCA) and Partial Least Squares (PLS) with Logistic Regression (LR), Linear Discriminant Analysis (LDA), Support Vector Machine (SVM), and Partial Least Squares-Discriminant Analysis (PLS-DA) based classifiers, the PLS-DA based model showed the maximum classification accuracy with 95 % based on LIBS data and 100 % based on Raman data. The reliability of the model was assessed using 4-fold cross-validation which showed a sensitivity of 90.28 % and specificity of 98.29 % for predictions based on LIBS data, and 99 % sensitivity and 99.82 % specificity for predictions relying on Raman data.

SIGNIFICANCE

The results show how the combination of multimodal spectroscopy with chemometric analysis enhances the applicability of spectroscopic techniques for plastic sorting. The classification model successfully classified seven types of post-consumer plastic samples based on combined LIBS and Raman data. With the home-built software for automated prediction, the system takes less than a second to predict the plastic type illustrating the potential of the method for translation to regular routine industrial applications.

Room-Temperature Self-Healing and Recyclable Self-Crosslinked Isosorbide-Based Adhesive Bioelastomer

Recently, renewable bio-based materials have received more and more attention due to environmental issues such as global warming and ecosystem destruction. In the present work, a series of isosorbide-based bioelastomers poly(isosorbide carbonate-co-butanediol aliphatic esters)s (PICBAs) are synthesized by a facile and economical two-step melt polycondensation. Due to the slightly self-crosslinking reaction of isosorbide, PICBAs exhibit excellent tensile strength and self-healing ability, the mechanical properties of PICBAs can recover over 95% after 48 h under room temperature. In addition, PICBAs can stick different substances, such as glass, rubber, plastic, and stones, and show better adhesive performance than 3M commercially available double-sided tape. Consequently, isosorbide-based bioelastomers PICBAs are of great potential to be used as environmentally friendly pressure-sensitive adhesives (PSA) in the future.

Biodegradable Biobased Polymers: A Review of the State of the Art, Challenges, and Future Directions

Biodegradable biobased polymers derived from biomass (such as plant, animal, marine, or forestry material) show promise in replacing conventional petrochemical polymers. Research and development have been conducted for decades on potential biodegradable biobased polymers such as polylactic acid (PLA), polyhydroxyalkanoates (PHAs), and succinate polymers. These materials have been evaluated for practicality, cost, and production capabilities as limiting factors in commercialization; however, challenges, such as the environmental limitations on the biodegradation rates for biodegradable biobased polymer, need to be addressed. This review provides a history and overview of the current development in the synthesis process and properties of biodegradable biobased polymers, along with a techno-commercial analysis and discussion on the environmental impacts of biodegradable biobased polymers. Specifically, the techno-commercial analysis focuses on the commercial potential, financial assessment, and life-cycle assessment of these materials, as well as government initiatives to facilitate the transition towards biodegradable biobased polymers. Lastly, the environmental assessment focuses on the current challenges with biodegradation and methods of improving the recycling process and reusability of biodegradable biobased polymers.

A critical review and analysis of plastic waste management practices in Rwanda

Plastic products are now essential commodities, yet their widespread disposal leads to environmental and human health effects, particularly in developing nations. Therefore, developing nations require comprehensive studies to assess the current state of plastic and plastic waste production to enhance plastic waste management practices. This review analyzes the import and export of plastic and the production of plastic waste in Rwanda, aiming to improve waste management practices. This review used open-access papers, reports, and websites dealing with plastic waste management. In this review, 58 articles from the Web of Science and 86 from other search engines were consulted to write this review. The findings revealed that the daily estimated plastic waste produced per person ranges between 0.012 and 0.056 kg. The estimated amount of plastic waste generated per person per year in Rwanda could be between 4.38 and 20.44 kg. Plastic waste accounts for between 1 and 8% of the total municipal solid waste produced per person per day in the country, which ranges from 219 to 255.5 kg. The average annual amount of imported plastics could reach 568.2881 tons, whereas the average quantity of exported plastics could reach 103.7414 tons. This shows that plastic management practices have not yet adopted technically advanced or improved practices, which should concern efforts to protect our environment. This study suggests approaches that can vastly improve plastic waste management and potentially open massive opportunities for the people of Rwanda.

Development of curcumin integrated smart pH indicator, antibacterial, and antioxidant waste derived Artocarpus lakoocha starch-based packaging film

Monitoring of food freshness is considered one of the crucial challenges for both customers/consumers and the food industries. In this study, we developed a curcumin-based starch film (F1) for pH-sensitive intelligent food packaging application. The starch was obtained from waste seeds of Artocarpus lakoocha (NS-MJF). The native starch underwent various physical and chemical modifications to yield modified starches (S1 [Autoclave heat treated], S2 [osmotic-pressure treated], S3 [citric acid treated]). The native starch was then used further for the formation of curcumin (2.5 % w/w)-based film (F1). We had analyzed these starches for solubility, colour analysis, biodegradability, oil absorption capacity, and moisture content, etc. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed favourable microstructures. The addition of curcumin to the starch enhanced the contact angle and elongation at the break of the resulting films. Antioxidant and antimicrobial assays, along with real-time freshness monitoring of chicken fillets, were also conducted. Thus, our findings may contribute to the optimization of pH-responsive biopolymer-based films for intelligent poultry packaging, promising advancements in food preservation and safety.

A study on the performance, structure, composition, and release behavior changes of polybutylene adipate terephthalic acid (PBAT) film during food contact

Polybutylene adipate terephthalic acid (PBAT) is an emerging biodegradable material in food packaging. However, concerns have been raised regarding the potential hazards it could pose to food safety. In this study, the changes of PBAT films during food contact and the release of small molecules were inestigated by a multiscale approach. On a macro-scale, the surface roughness of the films increased with the reduction in the concentration of food simulants and the increase in contact temperatures, especially after immersion in acidic food environments. On a micro-scale, the crystallinity (Xc) and degradation indexes (DI) of the films increased by 5.7-61.2% and 7.8-48.6%, respectively, which led to a decrease in thermal stability. On a scale approaching the molecular level, 2,4-di-tert-butylphenol (2,4-DTBP) was detected by gas chromatography-mass spectrometry (GC-MS/MS) with the highest migration content, and the release behavior of 2,4-DTBP was further investigated by migration kinetics. In addition, terephthalic acid (TPA), a hydrolysis product of PBAT, was detected in acidic food environments by liquid chromatography-mass spectrometry (LC-MS/MS). The results of this study could provide practical guidance and assistance to promote sustainable development in the field of food packaging.

Microplastic pollution promotes soil respiration: A global-scale meta-analysis

Microplastic (MP) pollution likely affects global soil carbon (C) dynamics, yet it remains uncertain how and to what extent MP influences soil respiration. Here, we report on a global meta-analysis to determine the effects of MP pollution on the soil microbiome and CO2 emission. We found that MP pollution significantly increased the contents of soil organic C (SOC) (21%) and dissolved organic C (DOC) (12%), the activity of fluorescein diacetate hydrolase (FDAse) (10%), and microbial biomass (17%), but led to a decrease in microbial diversity (3%). In particular, increases in soil C components and microbial biomass further promote CO2 emission (25%) from soil, but with a much higher effect of MPs on these emissions than on soil C components and microbial biomass. The effect could be attributed to the opposite effects of MPs on microbial biomass vs. diversity, as soil MP accumulation recruited some functionally important bacteria and provided additional C substrates for specific heterotrophic microorganisms, while inhibiting the growth of autotrophic taxa (e.g., Chloroflexi, Cyanobacteria). This study reveals that MP pollution can increase soil CO2 emission by causing shifts in the soil microbiome. These results underscore the potential importance of plastic pollution for terrestrial C fluxes, and thus climate feedbacks.

Beyond surface: Unveiling ecological and economic ramifications of microplastic pollution in the oceans

Every year, the global production of plastic waste reaches a staggering 400 million metric tons (Mt), precipitating adverse consequences for the environment, food safety, and biodiversity as it degrades into microplastics (MPs). The multifaceted nature of MP pollution, coupled with its intricate physiological impacts, underscores the pressing need for comprehensive policies and legislative frameworks. Such measures, alongside advancements in technology, hold promise in averting ecological catastrophe in the oceans. Mandated legislation represents a pivotal step towards restoring oceanic health and securing the well-being of the planet. This work offers an overview of the policy hurdles, legislative initiatives, and prospective strategies for addressing global pollution due to MP. Additionally, this work explores innovative approaches that yield fresh insights into combating plastic pollution across various sectors. Emphasizing the importance of a global plastics treaty, the article underscores its potential to galvanize collaborative efforts in mitigating MP pollution's deleterious effects on marine ecosystems. Successful implementation of such a treaty could revolutionize the plastics economy, steering it towards a circular, less polluting model operating within planetary boundaries. Failure to act decisively risks exacerbating the scourge of MP pollution and its attendant repercussions on both humanity and the environment. Central to this endeavor are the formulation, content, and execution of the treaty itself, which demand careful consideration. While recognizing that a global plastics treaty is not a panacea, it serves as a mechanism for enhancing plastics governance and elevating global ambitions towards achieving zero plastic pollution by 2040. Adopting a life cycle approach to plastic management allows for a nuanced understanding of possible trade-offs between environmental impact and economic growth, guiding the selection of optimal solutions with socio-economic implications in mind. By embracing a comprehensive strategy that integrates legislative measures and technological innovations, we can substantially reduce the influx of marine plastic litter at its sources, safeguarding the oceans for future generations.

Design strategy for blends of biodegradable polyester and thermoplastic starch based on a molecular dynamics study of the phase-separated interface

Molecular insight into the phase-separated interface formed when biodegradable polyesters and thermoplastic starch (TPS) are melt-blended is valuable for the design of composites. In this study, eight different interfaces combining four major biodegradable polyesters (PLA, PBS, PHB and PBAT) and two TPSs [unmodified TPS (nTPS) and citrate-modified TPS (cTPS)] were investigated by using molecular dynamics (MD) simulations. According to the MD simulation results, PBS, PHB and PBAT diffuse readily into the TPS and form compatible interfaces, whereas PLA is less compatible with the TPS. The results of tensile simulations show that PBS and PBAT adhere well to TPS; in particular, PBS/cTPS and PBAT/cTPS exhibit high interfacial-fracture energy (G). Both PLA and PHB blended with TPS exhibit low G because PLA is less compatible with TPS and PHB and TPS have low electrostatic interaction. The reason for the high G of PBS/cTPS and PBAT/cTPS is thought to be a combination of three factors: (i) formation of a deep compatible interface, (ii) suppression of void growth by electrostatic interactions and (iii) absorption of strain energy by a change in the conformation of the molecular chains. These three interfacial adhesion mechanisms should be considered when designing biodegradable polyester/TPS blends with good mechanical properties.

Eco-friendly zinc-metal-organic framework as a nucleating agent for poly (lactic acid)

Eco-friendly poly(L-lactic acid) (PLA) can be made more versatile, and its crystallization rate is accelerated by adding Zinc-based metal-organic framework (Zn-MOF) particles. Using differential scanning calorimetry (DSC), the non-isothermal melt crystallization behavior of biodegradable PLA nucleated by 0.3 to 3 wt% of Zn-MOF was examined. The non-isothermal melt crystallization kinetics parameters were determined using a modified Avrami model and Mo approach. Zn-MOF dramatically accelerated the crystallization process, as evidenced by several non-isothermal crystallization metrics, including the crystallization half-time and crystallization rate constant. The melt crystallization temperatures of the PLA-Zn-MOF composites, with contents of 0.7 and 1 wt%, were increased by 21 °C compared to the neat PLA. Using the Friedman isoconversional kinetic method, the neat PLA and PLA-Zn-MOF composites' effective activation energy values, ∆E, were determined. The ∆E values of PLA-Zn-MOF from 0.3 to 1 wt% Zn-MOF composites were lower than that of neat PLA. Moreover, polarized optical microscopy revealed the formation of numerous small-sized PLA spherulites upon Zn-MOF addition. The results indicate that the Zn-MOF (at concentrations of 0.7 to 1.0 wt%) can be used as an efficient nucleating agent for PLA, where it increases the melt crystallization temperature, nucleation density, and crystallinity without changing the crystalline structure, while also significantly reduces the effective activation energy and the size of spherulites. Additionally, scanning electron microscopy confirms good dispersion of Zn-MOF (0.3 to 1 wt%) within the PLA matrix.

Characterization of active films based on chitosan/polyvinyl alcohol integrated with ginger essential oil-loaded bacterial cellulose and application in sea bass (Lateolabrax japonicas) packaging

The poor mechanical properties, low water-resistance, and limited antimicrobial activity of chitosan (CS)/polyvinyl alcohol (PVA) based film limited its application in aquatic product preservation. Herein, bacterial cellulose (BC) was used to load ginger essential oil (GEO). The effects of the addition of BC and different concentrations of GEO on the physicochemical and antimicrobial activities of films were systematically evaluated. Finally, the application of sea bass fillets was investigated. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) analysis indicated dense networks were formed, which was verified by enhanced physical properties. The mechanical properties, barrier properties, and antimicrobial activities enhanced as GEO concentration increased. CPB0.8 (0.8 % GEO) film had better tensile strength (TS) and barrier performance, improved the quality, and extended the shelf-life of sea bass for another 6 days at least. Overall, active films are potential packaging materials for aquatic products.

Sustainable struggling: decoding microplastic released from bioplastics-a critical review

This comprehensive review delves into the complex issue of plastic pollution, focusing on the emergence of biodegradable plastics (BDPs) as a potential alternative to traditional plastics. While BDPs seem promising, recent findings reveal that a large number of BDPs do not fully degrade in certain natural conditions, and they often break down into microplastics (MPs) even faster than conventional plastics. Surprisingly, research suggests that biodegradable microplastics (BDMPs) could have more significant and long-lasting effects than petroleum-based MPs in certain environments. Thus, it is crucial to carefully assess the ecological consequences of BDPs before widely adopting them commercially. This review thoroughly examines the formation of MPs from prominent BDPs, their impacts on the environment, and adsorption capacities. Additionally, it explores how BDMPs affect different species, such as plants and animals within a particular ecosystem. Overall, these discussions highlight potential ecological threats posed by BDMPs and emphasize the need for further scientific investigation before considering BDPs as a perfect solution to plastic pollution.

Forefront Research of Foaming Strategies on Biodegradable Polymers and Their Composites by Thermal or Melt-Based Processing Technologies: Advances and Perspectives

The last few decades have witnessed significant advances in the development of polymeric-based foam materials. These materials find several practical applications in our daily lives due to their characteristic properties such as low density, thermal insulation, and porosity, which are important in packaging, in building construction, and in biomedical applications, respectively. The first foams with practical applications used polymeric materials of petrochemical origin. However, due to growing environmental concerns, considerable efforts have been made to replace some of these materials with biodegradable polymers. Foam processing has evolved greatly in recent years due to improvements in existing techniques, such as the use of supercritical fluids in extrusion foaming and foam injection moulding, as well as the advent or adaptation of existing techniques to produce foams, as in the case of the combination between additive manufacturing and foam technology. The use of supercritical CO2 is especially advantageous in the production of porous structures for biomedical applications, as CO2 is chemically inert and non-toxic; in addition, it allows for an easy tailoring of the pore structure through processing conditions. Biodegradable polymeric materials, despite their enormous advantages over petroleum-based materials, present some difficulties regarding their potential use in foaming, such as poor melt strength, slow crystallization rate, poor processability, low service temperature, low toughness, and high brittleness, which limits their field of application. Several strategies were developed to improve the melt strength, including the change in monomer composition and the use of chemical modifiers and chain extenders to extend the chain length or create a branched molecular structure, to increase the molecular weight and the viscosity of the polymer. The use of additives or fillers is also commonly used, as fillers can improve crystallization kinetics by acting as crystal-nucleating agents. Alternatively, biodegradable polymers can be blended with other biodegradable polymers to combine certain properties and to counteract certain limitations. This work therefore aims to provide the latest advances regarding the foaming of biodegradable polymers. It covers the main foaming techniques and their advances and reviews the uses of biodegradable polymers in foaming, focusing on the chemical changes of polymers that improve their foaming ability. Finally, the challenges as well as the main opportunities presented reinforce the market potential of the biodegradable polymer foam materials.

Biodegradation of various grades of polyethylene microplastics by Tenebrio molitor and Tenebrio obscurus larvae: Effects on their physiology

Polyethylene (PE) is the most productive plastic product and includes three major polymers including high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) variation in the PE depends on the branching of the polymer chain and its crystallinity. Tenebrio obscurus and Tenebrio molitor larvae biodegrade PE. We subsequently tested larval physiology, gut microbiome, oxidative stress, and PE degradation capability and degradation products under high-purity HDPE, LLDPE, and LDPE powders (<300 μm) diets for 21 days at 65 ± 5% humidity and 25 ± 0.5 °C. Our results demonstrated the specific PE consumption rates by T. molitor was 8.04-8.73 mg PE ∙ 100 larvae-1⋅day-1 and by T. obscurus was 7.68-9.31 for LDPE, LLDPE and HDPE, respectively. The larvae digested nearly 40% of the ingested three PE and showed similar survival rates and weight changes but their fat content decreased by 30-50% over 21-day period. All the PE-fed groups exhibited adverse effects, such as increased benzoquinone concentrations, intestinal tissue damage and elevated oxidative stress indicators, compared with bran-fed control. In the current study, the digestive tract or gut microbiome exhibited a high level of adaptability to PE exposure, altering the width of the gut microbial ecological niche and community diversity, revealing notable correlations between Tenebrio species and the physical and chemical properties (PCPs) of PE-MPs, with the gut microbiome and molecular weight change due to biodegradation. An ecotoxicological simulation by T.E.S.T. confirmed that PE degradation products were little ecotoxic to Daphnia magna and Rattus norvegicus providing important novel insights for future investigations into the environmentally-friendly approach of insect-mediated biodegradation of persistent plastics.

Third-generation D-lactic acid production using red macroalgae Gelidium amansii by co-fermentation of galactose, glucose and xylose

Macroalgae biomass has been considered as a promising renewable feedstock for lactic acid production owing to its lignin-free, high carbohydrate content and high productivity. Herein, the D-lactic acid production from red macroalgae Gelidium amansii by Pediococcus acidilactici was investigated. The fermentable sugars in G. amansii acid-prehydrolysate were mainly galactose and glucose with a small amounts of xylose. P. acidilactici could simultaneously ferment the mixed sugars of galactose, glucose and xylose into D-lactic acid at high yield (0.90 g/g), without carbon catabolite repression (CCR). The assimilating pathways of these sugars in P. acidilactici were proposed based on the whole genome sequences. Simultaneous saccharification and co-fermentation (SSCF) of the pretreated and biodetoxified G. amansii was also conducted, a record high of D-lactic acid (41.4 g/L) from macroalgae biomass with the yield of 0.34 g/g dry feedstock was achieved. This study provided an important biorefinery strain for D-lactic acid production from macroalgae biomass.

Photocatalytic Upgrading of Polylactic Acid Waste into Alanine under Mild Conditions

Polylactic acid (PLA) has attracted increasing interest as a sustainable plastic because it can be degraded into CO2 and H2O in nature. However, this process is sluggish, and even worse, it is a CO2-emitting and carbon resource waste process. Therefore, it is highly urgent to develop a novel strategy for recycling post-consumer PLA to achieve a circular plastic economy. Herein, we report a one-pot photoreforming route for the efficient and selective amination of PLA waste into value-added alanine using CoP/CdS catalysts under mild conditions. Results show the alanine production rate can reach up to 2.4 mmol gcat -1 h-1, with a high selectivity (>75 %) and excellent stability. Time-resolved transient absorption spectra (TAS) reveal that CoP can rapidly extract photogenerated electrons from CdS to accelerate proton reduction, favoring hole-dominated PLA oxidation to coproduce alanine. This study offers an appealing way for upcycling PLA waste and creates new opportunities for green synthesis of amino acids.

Arbuscular Mycorrhizal Fungus Alleviates Charged Nanoplastic Stress in Host Plants via Enhanced Defense-Related Gene Expressions and Hyphal Capture

Contamination of small-sized plastics is recognized as a factor of global change. Nanoplastics (NPs) can readily enter organisms and pose significant ecological risks. Arbuscular mycorrhizal (AM) fungi are the most ubiquitous and impactful plant symbiotic fungi, regulating essential ecological functions. Here, we first found that an AM fungus, Rhizophagus irregularis, increased lettuce shoot biomass by 25-100% when exposed to positively and negatively charged NPs vs control, although it did not increase that grown without NPs. The stress alleviation was attributed to the upregulation of gene expressions involving phytohormone signaling, cell wall metabolism, and oxidant scavenging. Using a root organ-fungus axenic growth system treated with fluorescence-labeled NPs, we subsequently revealed that the hyphae captured NPs and further delivered them to roots. NPs were observed at the hyphal cell walls, membranes, and spore walls. NPs mediated by the hyphae were localized at the root epidermis, cortex, and stele. Hyphal exudates aggregated positively charged NPs, thereby reducing their uptake due to NP aggregate formation (up to 5000 nm). This work demonstrates the critical roles of AM fungus in regulating NP behaviors and provides a potential strategy for NP risk mitigation in terrestrial ecosystems. Consequent NP-induced ecological impacts due to the affected AM fungi require further attention.

Castor-oil biobased foam: the effect of the composition on the physical and mechanical properties via a statistical mixture design

PU foams are versatile materials that find applications in a wide range of products, from upholstery to packaging and construction. These foams consist primarily of two components, polyol and prepolymer, and their concentrations play a crucial role in determining their physical and mechanical properties. A second-order mixture design approach is used in this work to identify the significant components and their contributions on the physical-mechanical properties of biodegradable castor oil-based foams. The experimental design includes three components: two types of polyols and one prepolymer. These components are varied in nine distinct conditions to evaluate their effects on properties such as expansion rate, bulk density, compressive strength, and tensile strength. The Scheffé's quadratic model coefficients exhibit R-squared values higher than 0.84 in most cases. Chemical analysis using infrared spectroscopy confirms the successful formation of the urethane bond during the manufacturing process. The biobased foams developed in this work have densities ranging between 61 and 100 kg m-3, compressive modulus of 11-15 MPa and compressive strength between 273 and 429 kPa. The tensile modulus varies between 3.2 and 4.9 MPa, with a tensile strength in the range of 370-500 kPa. These results highlight the potential of biodegradable castor oil-based foams as promising alternative materials to traditional synthetic foams.