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Plastic pellets, the pre-production form of many plastic products, undergo oxidation and photodegradation upon exposure to oxygen and sunlight, resulting in visible color changes. This study examines the impact of environmental aging on the mechanical interactions between pellet-derived microplastics and lipid bilayers, a critical component of biological membranes. Polyethylene pellets were collected from La Pineda beach near Tarragona, Spain, and categorized by chemical composition and yellowing index, an indicator of aging. The hydrophilicity of these pellets was assessed using contact angle measurements. Microplastics were produced by grinding and filtering these pellets and subsequently dispersed around a free-standing lipid bilayer within a 3D microfluidic chip to investigate their interactions. Our results reveal that aged microplastics exhibit a significantly increased adhesive interaction with lipid bilayers, leading to greater bilayer stretching. Theoretical modeling indicates a linear relationship between the adhesive interaction and the contact angle of the pellets, reflecting their hydrophilicity. These findings emphasize the increased mechanical impact of aged microplastics on biological membranes, which raises concerns about their potential toxicological effects on living organisms. This study highlights the importance of understanding the interactions between environmentally aged microplastics and biological systems to assess their risks, as these may differ significantly from pristine microplastics often studied under laboratory conditions. [ABSTRACT FROM AUTHOR]

UNLABELLED: Biodegradable plastics are urgently needed to replace petroleum-derived polymeric materials and prevent their accumulation in the environment. To this end, we isolated and characterized a halophilic and alkaliphilic bacterium from the Great Salt Lake in Utah. The isolate was identified as a Halomonas species and designated CUBES01. Full-genome sequencing and genomic reconstruction revealed the unique genetic traits and metabolic capabilities of the strain, including the common polyhydroxyalkanoate (PHA) biosynthesis pathway. Fluorescence staining identified intracellular polyester granules that accumulated predominantly during the strains exponential growth, a feature rarely found among natural PHA producers. CUBES01 was found to metabolize a range of renewable carbon feedstocks, including glucosamine and acetyl-glucosamine, as well as sucrose, glucose, fructose, and further glycerol, propionate, and acetate. Depending on the substrate, the strain accumulated up to ~60% of its biomass (dry wt/wt) in poly(3-hydroxybutyrate), while reaching a doubling time of 1.7 h at 30°C and an optimum osmolarity of 1 M sodium chloride and a pH of 8.8. The physiological preferences of the strain may not only enable long-term aseptic cultivation but also facilitate the release of intracellular products through osmolysis. The development of a minimal medium also allowed the estimation of maximum polyhydroxybutyrate production rates, which were projected to exceed 5 g/h. Finally, also, the genetic tractability of the strain was assessed in conjugation experiments: two orthogonal plasmid vectors were stable in the heterologous host, thereby opening the possibility of genetic engineering through the introduction of foreign genes. IMPORTANCE: The urgent need for renewable replacements for synthetic materials may be addressed through microbial biotechnology. To simplify the large-scale implementation of such bio-processes, robust cell factories that can utilize sustainable and widely available feedstocks are pivotal. To this end, non-axenic growth-associated production could reduce operational costs and enhance biomass productivity, thereby improving commercial competitiveness. Another major cost factor is downstream processing, especially in the case of intracellular products, such as bio-polyesters. Simplified cell-lysis strategies could also further improve economic viability.

Plastic pollution, a pervasive environmental crisis, arises from the improper disposal of non-biodegradable plastics, endangering species and ecosystems worldwide. While microplastics (MPs) have been extensively studied in various ecosystems, they have received scant attention in port environments, despite their pervasive presence. This review selected published articles conducted in ports worldwide between 2010 and 2024 to determine the concentration, accumulation characteristics, and driving factors. A total of 57 studies across 78 ports met the selection criteria, examining water, sediment, and biota in 49, 51, and 23 ports, respectively. The average concentrations of MPs in water collected by net and grab sampling, sediment, fish, and invertebrates were approximately 39.2 ± 68.4 items/m3, 4100.7 ± 5761.8 items/m3, 243.6 ± 240.2 items/kg, 26.1 ± 21.1 items/individual, and 9.4 ± 8.1 items/individual in ports worldwide, respectively. Asia and the Americas exhibited the highest concentration of MPs in ports across all media. The dominant MP morphotypes included fibers, fragments, films, foams, pellets, and spheres, with sizes frequently between 1 and 1000 μm in biota and water and between 1 and 5 mm in sediments. Port structures and the presence of rivers are key drivers of MP accumulation. MP pollution in ports poses potential ecological and health risks. Among the studied ports, 23% had MP numbers in sediment greater than the predicted no effect concentration (PNEC). The presence of MP in biota and the capability of MP to adsorb other contaminants pose a threat to human health. [ABSTRACT FROM AUTHOR]

Pyrolysis of modern biomass is a sustainable technique to produce chemicals, yet efficient and selective conversion remains challenging. We studied biomass pyrolysis catalyzed by graphene oxide for the production of levoglucosan, a chemical with potential applications in biodegradable plastics and surfactants. We tested model compounds containing 40–100 wt% cellulose, poplar biomass, and we modelled the role of graphene oxide by calculations using the density functional theory. Results for model compounds show that levoglucosan production is higher for compounds containing less than 50% cellulose. By contrast, levoglucosan yield are reduced for model compounds having more than 60 wt% cellulose, because graphene oxide induced the breakdown of levoglucosan. Experiments show that pyrolysis of poplar biomass with 5 wt% graphene oxide increased about three times the yield of levoglucosan, compared to non-catalyzed pyrolysis. Enhanced levoglucosan formation is explained by the formation of a six-membered ring intermediate. [ABSTRACT FROM AUTHOR]

Gamma-aminobutyric acid (GABA), which is synthesized from l -glutamic acid via glutamate decarboxylase (Gad), is used as food, supplements, and biodegradable plastics. Our previous study demonstrated an Escherichia coli mutant (ΔΔ) strain, lacking type I NADH dehydrogenase (NDH-I) and cytochrome bo 3 oxidase (Cyt bo 3), produced 7 g/L glutamic acid on MS1 glucose-minimal medium. In this study, the ΔΔ strain was used for improving GABA production. A plasmid (pMBL19- gadB ′) expressing a mutated E. coli GadB (Glu89Gln/Δ452-466), retaining activity at neutral pH, was introduced into the ΔΔ strain and its parent strain (W1485). The ΔΔ strain carrying pMBL19- gadB ′ exhibited a twofold increase in GABA production compared to the W1485 strain carrying pMBL19- gadB ′. Deleting the C-terminal (Δ471–511) of GadC antiporter in the ΔΔ strain further improved GABA yield to 1.5 g/L when cultured in MS1 glucose-minimal medium. On the other hand, a large amount of glutamic acid produced by the ΔΔ strain was not fully converted to GABA, likely due to the inhibition of GadB activity by the accumulation of acetic acid. Although there is room for improvement, these results indicate the efficacy of the ΔNDH-IΔCyt bo 3 double mutation in augmenting GABA production. [ABSTRACT FROM AUTHOR]

Plastics that can metabolize in oceans are highly sought for a sustainable future. In this work, we report the noncovalent synthesis of unprecedented plastics that are mechanically strong yet metabolizable under biologically relevant conditions owing to their dissociative nature with electrolytes. Salt-bridging sodium hexametaphosphate with di- or tritopic guanidinium sulfate in water forms a cross-linked supramolecular network, which is stable unless electrolytes are resupplied. This unusual stability is caused by a liquid-liquid phase separation that expels sodium sulfate, generated upon salt bridging, into a water-rich phase. Drying the remaining condensed liquid phase yields glassy plastics that are thermally reshapable, such as thermoplastics, and usable even in aqueous media with hydrophobic parylene C coating. This approach can be extended to polysaccharide-based supramolecular plastics that are applicable for three-dimensional printing. [ABSTRACT FROM AUTHOR]

Fumarate is an unsaturated dicarboxylic acid useful as a raw material for unsaturated polyester resins, polybutylene succinate (PBS), poly(propylene fumarate) (PPF), plasticisers, and other products. Biodegradable plastics derived from fumarate are an attractive solution to the serious environmental pollution caused by plastic disposal. A new fumarate production from CO2 and biobased pyruvate using enzymes in aqueous media under ambient temperature and pressure is an environmental approach to overcome plastic pollution and achieve CO2 capture, utilization and storage (CCUS). In this work, fumarate production from pyruvate and low-concentration CO2 below 15% captured from the gas phase using 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES)-NaOH buffer solution with a multi-enzyme system consisting of pyruvate carboxylase from a bovine liver (PC; EC 6.4.1.1), recombinant malate dehydrogenase from bacteria (MDH; EC 1.1.1.37) and fumarase from a porcine heart (FUM; EC 1.1.1.37) in the presence of adenosine 5′-triphosphate (ATP) and NADH was investigated. It was found that pyruvate can be converted into L -malate in high yields (more than 80%) directly using 15% CO2 equivalent to exhaust gas as a carboxylating agent using a dual-enzyme system consisting of PC and MDH in the presence of ATP and NADH after 5 h incubation. Moreover, fumarate production from 15% CO2 and pyruvate as raw materials was accomplished using a dual-enzyme system consisting of PC and MDH. [ABSTRACT FROM AUTHOR]

The depletion of global petrochemical resources, coupled with the environmental challenges arising from the extensive use of traditional plastics, has led to greater interest in the research of environmentally friendly biodegradable materials that can be used in various applications. The weak water barrier properties of collagen hydrolysate (CH) obtained from leather industry trimming waste seriously limit its practical application areas. In this study, CH/sodium alginate (CH/SA)-based films were produced using the solution casting method because they are non-toxic and biocompatible. The CH/SA composition with the best water barrier property was selected and cross-linked with transglutaminase (TG), genipin (GP), and tannic acid (TA). Cross-linking significantly increases the mechanical strength, thermal ability, and hydrophobicity of the films, thereby reducing their WVP and WS. The film sample CH40/SA60/GP0.4%, out of all the examined specimens, demonstrated superior overall performance, characterized by a TS of 21.209 MPa and a WS of 19.896%. The results indicate that biodegradable films serve as a promising foundation for the development of packaging materials. Consequently, this study offers an effective approach to creating high-performance, environmentally friendly, and degradable CH/SA-based films and products. [ABSTRACT FROM AUTHOR]

Natural plant fiber‐based packaging materials emerges as sustainable alternatives to conventional plastic and non‐biodegradable packaging. This paper presents an extensive review of the current technological status quo and commercial applications of natural plant fiber‐based packaging such as fiber‐based foams, molded pulp packaging, fiber‐based bottles, fiber‐based flexible packaging, fiber‐based blister packaging and stretchable paper. It focuses on the manufacturing processes and newest technology advancement of environmentally sustainable materials, meanwhile, the currently industry‐leading, cutting‐edge commercial products also are discussed. In conclusion, the paper advocates for the pivotal role natural plant fiber‐based packaging plays in transforming the packaging industry, addressing waste reduction, resource conservation, and climate change. It encourages the wider adoption of these materials while acknowledging the complexities involved and the need for continuous research and development to ensure their viability and effectiveness in meeting stringent packaging requirements. [ABSTRACT FROM AUTHOR]

Petroleum-derived single-use plastics have dominated a range of material applications, including packaging and service ware (e.g., water bottles, food containers, and drinking straws). However, despite their short-lived service life, the inherent durability, and stability of these plastics have resulted in significant environmental accumulation and spill, contaminating both aquatic and land ecosystems. Consequently, there is a surging interest in the development of bioplastics as a sustainable alternative to petrochemical derived plastics that align with circular economy principles. Among potential materials, cellulose acetate (CA) showcases impressive mechanical properties, optical characteristics, melt processability, and compostability. However, due to its hygroscopic behavior, inferior barrier properties, and lack of dimensional stability, CA applications in the packaging industry are minimal. In this research, the acetylation of lignin and its use as a functional filler for CA matrix was studied. The impact of varying lignin loadings (up to 30 wt.%) on the tensile, morphological, barrier, and viscoelastic properties of the resulting materials was investigated. A thorough characterization of the compression-molded acetylated lignin-CA films revealed a reduction in water uptake (by 59% over baseline), up to a 41.5% reduction in water vapor permeability, and enhanced tensile properties with melt flowability. In summary, the examined films displayed favorable characteristics for use in food and other packaging applications. Consequently, they serve as low carbon footprint, and eco-friendly substitutes for conventional petrochemical-based packaging materials. [ABSTRACT FROM AUTHOR]

Poly(butylene adipate‐co‐terephthalate) (PBAT) is popular because of its low cost, biodegradability, good processing properties, flexibility, and mechanical features. In this study, we explore the potential of PBAT‐based bioplastics by adding AgVO3 nanorods with PBAT to reduce costs. We produced nanocomposite films of PBAT reinforced with 1, 3, and 5 wt% of AgVO3 nanorods using solvent casting. The inclusion of AgVO3 in the structure of PBAT was investigated through Fourier transform infrared spectroscopy, x‐ray diffraction, and scanning electron microscopy. The nanocomposite films demonstrate excellent properties, surpassing those of single‐component blends, enhancing mechanical properties, and improving the barrier properties of nanocomposite films. The water vapor transmission rate of AgVO3 reinforced (5 wt%) nanocomposite films improved by 42.45% compared to pure PBAT films. The tensile strength of the PBA‐3 film was 37.19 MPa, exhibiting higher strength than the films produced from clean PBAT (19.73 MPa). The AgVO3‐reinforced films demonstrated increased resistance to moisture and water, as indicated by their higher water contact angle values (88.04°). Food‐borne bacteria like Staphylococcus aureus and Escherichia coli have been stable to the antibacterial activity of the nanocomposites on the addition of AgVO3.The potential applications of these nanocomposite films in food packaging are promising, offering a sustainable and effective solution to food preservation. Highlights: The AgVO3‐filled poly(butylene adipate‐co‐terephthalate) (PBAT) nanocomposite films exhibit superior mechanical, barrier, and resistance to moisture and water compared to neat PBAT films.The water vapor transmission rate of the film is significantly enhanced, with a 42.45% enhancement in films reinforced with 5 wt% AgVO3.AgVO3‐filled PBAT nanocomposites demonstrate effective antibacterial activity against Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

The pressing need to mitigate climate change and drastically reduce environmental pollution and loss of biodiversity has precipitated a so-called energy transition aimed at the decarbonization of energy and defossilization of the chemical industry. The goal is a carbon-neutral (net-zero) society driven by sustainable energy and a circular bio-based economy relying on renewable biomass as the raw material. It will involve the use of green carbon, defined as carbon derived from terrestrial or aquatic biomass or organic waste, including carbon dioxide and methane emissions. It will also necessitate the accompanying use of green hydrogen that is generated by electrolysis of water using a sustainable source of energy, e.g. solar, wind or nuclear. Ninety per cent of the industrial chemicals produced in oil refineries are industrial monomers that constitute the precursors of a large variety of polymers, many of which are plastics. Primary examples of the latter are polyolefins such as polyethylene, polypropylene, polyvinyl chloride and polystyrene. Polyolefins are extremely difficult to recycle back to the olefin monomers and discarded polyolefin plastics generally end up as the plastic waste that is responsible for the degradation of our natural habitat. By contrast, waste biomass, such as the lignocellulose contained in forestry residues and agricultural waste, constitutes a renewable feedstock for the sustainable production of industrial monomers and the corresponding polymers. The latter could be the same polyolefins that are currently produced in oil refineries but a more attractive long-term alternative is to produce polyesters and polyamides that can be recycled back to the original monomers: a paradigm shift to a truly bio-based circular economy on the road to a net-zero chemical industry. This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'. [ABSTRACT FROM AUTHOR]

Highlights Biodegradable biobased polymers are a promising solution to reduce the dependence on conventional plastics and minimize their environmental impact. This work evaluated the recycling capacity of a biodegradable polymer (MaterBi) and its composite with agave fibers. The materials were reprocessed by several cycles using compression molding. Service life simulation was performed using accelerated weathering. Samples from each reprocessing cycle were characterized in terms of melt flow index (MFI), color, porosity, water absorption, compostability, and mechanical and thermal properties. The MFI of MaterBi increased with each cycle, going from 3.5 to 95 g/10 min for the first to sixth cycles and from 2 to 117 g/10 min for the first and fourth cycles for the biocomposite. Reprocessing produced chain scission and modified the thermal and mechanical properties. MaterBi exhibited competitive mechanical properties compared to conventional polymers, even after four reprocessing cycles (tensile, flexural, and impact strengths of 27, 55 MPa, and 30 J/m). Besides potential cost reductions, the agave fiber addition positively affected the tensile and flexural modulus, which remained after the fourth cycle in 1100 and 2300 MPa. The results confirmed that MaterBi and its biocomposites can be recycled for several cycles, extending their useful life before final biodegradation. MaterBi (MB) and its agave fiber biocomposites are suitable for reprocessing. MB tensile and flexural properties remained stable after four reprocessing cycles. Agave fibers make MB more prone to weathering, impacting its properties. MB and its biocomposites degrade in water and compost conditions. [ABSTRACT FROM AUTHOR]

Despite the urgent need for accurate and robust observations of microplastics in the marine environment to assess current and future environmental risks, existing procedures remain labour-intensive, especially for smaller-sized microplastics. In addition to this, microplastic analysis faces challenges due to environmental weathering, impacting the reliability of research relying on pristine plastics. This study addresses these knowledge gaps by testing the robustness of two automated analysis techniques which combine machine learning algorithms with fluorescent colouration of Nile red (NR)-stained particles. Heterogeneously shaped uncoloured microplastics of various polymers—polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC)—ranging from 100 to 1000 µm in size and weathered under semi-controlled surface and deep-sea conditions, were stained with NR and imaged using fluorescence stereomicroscopy. This study assessed and compared the accuracy of decision tree (DT) and random forest (RF) models in detecting and identifying these weathered plastics. Additionally, their analysis time and model complexity were evaluated, as well as the lower size limit (2–4 µm) and the interoperability of the approach. Decision tree and RF models were comparably accurate in detecting and identifying pristine plastic polymers (both > 90%). For the detection of weathered microplastics, both yielded sufficiently high accuracies (> 77%), although only RF models were reliable for polymer identification (> 70%), except for PET particles. The RF models showed an accuracy > 90% for particle predictions based on 12–30 pixels, which translated to microplastics sized < 10 µm. Although the RF classifier did not produce consistent results across different labs, the inherent flexibility of the method allows for its swift adaptation and optimisation, ensuring the possibility to fine-tune the method to specific research goals through customised datasets, thereby strengthening its robustness. The developed method is particularly relevant due to its ability to accurately analyse microplastics weathered under various marine conditions, as well as ecotoxicologically relevant microplastic sizes, making it highly applicable to real-world environmental samples. [ABSTRACT FROM AUTHOR]

Knowledge on the variation of yield and water use efficiency under different mulching methods is important for guiding rained maize production in the Loess Plateau area. In this study, eight different plastic film mulching methods was established to analyze the maize growth, soil water content and soil temperature changes of dryland maize, and increase yield and water use efficiency (WUE). The field experiment was conducted in 2019, and eight treatments were set up, including a traditional flat planting without mulching (CK), ridge-furrow with ridges mulching black plastic film and furrows mulching straw (HJ), ridge-furrow with ridges mulching black plastic film and furrows bare (HL), ridge-furrow with ridges mulching liquid plastic film and furrows mulching straw (YJ), ridge-furrow with ridges mulching liquid plastic film and furrows bare (YL), ridge-furrow with ridges mulching biodegradable plastic film and furrows mulching straw (SJ), ridge-furrow with ridges mulching biodegradable plastic film and furrows bare (SL) and ridge-furrow with ridges bare and furrows mulching straw (NJ). Furthermore, the AHP-TOPSIS was employed to evaluate the optimal mulching method for maize. The results showed that compared with CK and NJ treatment, the soil water content and soil storage were significantly changes with other treatments in the reproductive period of maize. Among the six mulching methods, maize yield in HJ, HL, YJ, YL, SJ, and SL treatments were 46.28%, 61.95%, 70.30%, 51.02%, 52.02% and 53.53% significantly greater than CK treatment. In addition, dryland maize WUE was 66.53% and 84.01% higher in the YJ and YL treatments with ridges mulching liquid plastic film than in the CK treatment, respectively. The optimal treatments of economic benefits were YL and HJ. Through AHP-TOPSIS comprehensive analysis, the optimal mulching methods were YL and HJ treatment. Current field trials indicate that YL treatment could serve as a promising option to improve dryland maize yield, WUE, and reducing environmental risks in the Loess Plateau of China. [ABSTRACT FROM AUTHOR]

Plastic waste and wastewater are indeed significant environmental issues that have wide‐ranging impacts on ecosystems, human health, and the economy. This study outlines the synthesis of biodegradable polyvinyl alcohol (PVA)–starch polymeric films incorporating multiwalled carbon nanotubes (MWCNTs) derived from plastic waste and unzipped carbon nanotubes oxides (UMCNOs) as co‐filled nanomaterials. These films were formulated based on data generated using a mixture design method in Design Expert 13 software, resulting in the synthesis of 19 films utilizing five types of PVA–starch polymer solutions (Types A–E). The synthesized films underwent characterization to study their surface morphology via scanning electron microscope and Fourier transform infrared spectroscopy analysis. Subsequently, the films were individually subjected to vacuum filtration, through which cationic dyes such as methylene blue (MB) and anionic dye Congo red (CR) were passed in batches. The highest removal efficiency of 96.43% for MB dye was achieved, accompanied by an exceptionally high flux of 3146.78 LMH. Similarly, the maximum removal of 88.08% for CR was observed with a flux of 1512.66 LMH. The renewable active sites mechanism resulted in increased dye removal with every cycle. Results indicated efficient reusability, particularly when washed with ethanol–water solution. [ABSTRACT FROM AUTHOR]

A homo-aromatic polyester was produced from glucose for the first time. Aromatic polyhydroxyalkanoate (PHA) was produced to the highest titer yet achieved. 3D model-based rational engineering of PHA synthase was used to enhance aromatic PHA production. Polymer production was enhanced by utilizing heterologous phasins. Pilot-scale fermentative production of aromatic PHAs was successful. We report the development of a metabolically engineered bacterium for the fermentative production of polyesters containing aromatic side chains, serving as sustainable alternatives to petroleum-based plastics. A metabolic pathway was constructed in an Escherichia coli strain to produce poly[ d -phenyllactate(PhLA)], followed by three strategies to enhance polymer production. First, polyhydroxyalkanoate (PHA) granule-associated proteins (phasins) were introduced to increase the polymer accumulation. Next, metabolic engineering was performed to redirect the metabolic flux toward PhLA. Furthermore, PHA synthase was engineered based on in silico simulation results to enhance the polymerization of PhLA. The final strain was capable of producing 12.3 g/l of poly(PhLA), marking it the first bio-based process for producing an aromatic homopolyester. Additional heterologous gene introductions led to the high level production of poly(3-hydroxybutyrate- co -11.7 mol% PhLA) copolymer (61.4 g/l). The strategies described here will be useful for the bio-based production of aromatic polyesters from renewable resources. Graphical abstract [Display omitted] The production of polyhydroxyalkanoates (PHAs) containing aromatic repeating units has been studied for decades, but has yet to be demonstrated in large-scale fermentation. This study reports the successful production of aromatic polyesters from glucose in high titers that was performed both in lab-scale (5 l) and pilot-scale (30 l) fermenters. Therefore, the current Technology Readiness Level (TRL) of this technology lies between 4 and 5. To advance this technology for industrialization, demonstration in industry-scale fermenters and the development of large-scale downstream processes will be necessary. Nevertheless, given the ongoing development of various fermentation technologies and purification processes for other PHAs, we anticipate that the industrialization of aromatic PHAs is feasible, potentially replacing petroleum-based aromatic polymers for use as commodity, engineering, and biomedical plastics. Lee et al. report the fermentative production of aromatic polyesters, which can serve as sustainable alternatives to petroleum-based plastics. This represents the first instance of homo-aromatic polyester production using glucose. Further pathway engineering facilitated the production of poly(3-hydroxybutyrate- co - d -phenyllactate), achieving the highest titer of aromatic polyester reported using microorganisms thus far. [ABSTRACT FROM AUTHOR]

Microbial fermentation has provided fermented foods and important chemicals such as antibiotics, amino acids, and vitamins. Metabolic engineering of synthetic microbes has expanded the range of compounds produced by fermentation. Petroleum-derived aromatic compounds are widely used in industry as raw materials for pharmaceuticals, dyes, and polymers and are in great demand. This review highlights the current efforts in the microbial production of various aromatic chemicals such as aromatic amines, cinnamic acid derivatives, and flavoring aromatics, including their biosynthesis pathways. In addition, the unique biosynthetic mechanism of pyrazine, a heterocyclic compound, from amino acids is described to expand the use of biomass-derived aromatic compounds. I also discuss our efforts to develop high-performance bioplastics superior to petroleum plastics from the aromatic compounds produced by microbial fermentation. [ABSTRACT FROM AUTHOR]

Fused deposition molding (FDM) is a commonly used 3D printing method, and polylactic acid (PLA) has become one of the most important raw materials for this technology due to its excellent warping resistance. However, its mechanical properties are insufficient. Polybutylene adipate terephthalate (PBAT) is characterized by high toughness and low rigidity, which can complement the performance of PLA. The biodegradable polymers produced by blending the two have thus been used to replace petroleum-based plastics in recent years, but the high cost of the blends has limited their wide applications. Introducing plant fibers into the blends can not only maintain biodegradability and improve the overall performance of the plastics but also reduce their costs greatly. In this study, the PBAT/PLA blends with a mass ratio of 70/30 were selected and mixed with wood flour (WF) to prepare ternary composites using a FDM 3D printing technique. The effects of WF dosage on the mechanical properties, thermal properties, surface wettability, and melt flowability of the composites were investigated. The results showed that the proper amount of WF could improve the tensile and flexural moduli of the composites, as well as the crystallinity and hydrophobicity of the printed specimens increased with the content of WF, while the melt flow rate decreased gradually. Compared to PBAT/PLA blends, WF/PBAT/PLA composites are less costly, and the composite containing 20 wt.% WF has the best comprehensive performance, showing great potential as raw material for FDM 3D printing. [ABSTRACT FROM AUTHOR]

Pollution from plastics is a global problem that threatens the biosphere for a host of reasons, including the time scale that it takes for most plastics to degrade. Biodegradation is an ideal solution for remediating bioplastic waste as it does not require the high temperatures necessary for thermal degradation and does not introduce additional pollutants into the environment. Numerous organisms can scavenge for bioplastics, such as polylactic acid (PLA) or poly‐(R)‐hydroxybutyrate (PHB), which they can use as an energy source. Recently, a promiscuous PHBase from the thermophilic soil bacterium Lihuaxuella thermophila (LtPHBase) was identified. LtPHBase can accommodate many substrates, including PHB granules and films and PHB block copolymers, as well as the unrelated polymers polylactic acid (PLA) and polycaprolactone (PCL). LtPHBase uses the expected Ser–His–Asp catalytic triad for hydrolysis at an optimal enzyme activity near 70°C. Here, the 1.75 Å resolution crystal structure of apo LtPHBase is presented and its chemical stability is profiled. Knowledge of its substrate preferences was extended to different‐sized PHB granules. It is shown that LtPHBase is highly resistant to unfolding, with barriers typical for thermophilic enzymes, and shows a preference for low‐molecular‐mass PHB granules. These insights have implications for the long‐term potential of LtPHBase as an industrial PHB hydrolase and shed light on the evolutionary role that this enzyme plays in bacterial metabolism. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoate (PHA), specifically poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(3HB-co-3HHx), PHBHHx) with physical properties governed by the 3-hydroxyhexanoate (3HHx) mole fraction, is a promising bioplastic. Although engineered strains used to produce P(3HB-co-3HHx) with various 3HHx mole contents and fermentation techniques have been studied, mass production with specific 3HHx fractions and monomers depends on the batch, supply of substrates, and strains, resulting in the time-consuming development of strains and complex culture conditions for P(3HB-co-3HHx). To overcome these limitations, we blended poly(3-hydroxybutyrate) [(P(3HB), produced from C. necator H16] and P(3HB-co-20 mol%3HHx) [from C. necator 2668/pCB81] to prepare films with various 3HHx contents. We evaluated the molecular weight and physical, thermal, and mechanical properties of these films and confirmed the influence of the 3HHx monomer content on the mechanical and thermal properties as well as degradability of the blended P(3HB-co-3HHx) films containing various 3HHx mole fractions, similar to that of original microbial-based P(3HB-co-3HHx). Moreover, the degradation rate analyzed via Microbulbifer sp. was >76% at all blending ratios within 2 days, whereas a weaker effect of the 3HHx mole fraction of the blended polymer on degradation was observed. P(3HB-co-3HHx) could be produced via simple blending using abundantly produced P(3HB) and P(3HB-co-20 mol%HHx), and the resulting copolymer is applicable as a biodegradable plastic. [ABSTRACT FROM AUTHOR]

A model based on the fitting of stress–strain data by tensile tests of bio-composites made of a bioplastic (polybutylene succinate (PBS)) and brewer spent grain filler (BSGF) is developed. Experimental tests were performed for various concentrations of BSGF in the range from 2% to 30%. The model is suitable for describing the elastic–plastic behavior of these materials in terms of two mechanical parameters, tensile stress and tensile stiffness (or Young's modulus), depending on the filler concentration. The mechanical characteristics, derived from the fit parameters, show good agreement with the experimental data. The mathematical model used here could be an important aid for the experimentation and manufacturing process as it allows the prediction of the mechanical tensile parameters of a mixture with different filler concentrations, avoiding the long and complex preparation cycle of bio-composites, as well as the specific mechanical tests. The physical properties required by the objects created with the PBS–BSGF bio-composite by the partners/stakeholders of the research project co-financing this research can be quite different; therefore, a mathematical model that predicts some of the mechanical properties in terms of the mixture composition may be useful to speed up the selection of the required amount of BSGF in the mixture. [ABSTRACT FROM AUTHOR]

The fate of biobased and biodegradable cellulose-derived plastics in landfills represents an important topic from economic and environmental points of view. Anaerobic digestion is a cost-effective waste-to-energy technology. The behaviour of six polymer types—that is, cellulose (C), cellulose acetate (CA), viscose (V), nanocellulose (NC), acetate textile (AT), and heteropolysaccharide pectin (P)—was studied under anaerobic batch mesophilic conditions in a landfill leachate for 147 days. The cumulative biogas production was as follows: C>V=CA>>AT>>NC=P. Metagenomic analysis revealed notable variations in the proportion of bacterial and archaeal domains with the highest archaeal abundance in the presence of CA (80.2%) and C (78.5%). At the end of digestion, cellulolytic, hydrolytic, and dehydrogenase activities were measured in the intact samples, as well as the liquid and solid fractions, under aerobic and anaerobic conditions. Cellulolytic activity in P was detected only in the pellet, while in NC, activity was mostly in the supernatant under both aerobic and anaerobic conditions. Scanning electron microscopy and confocal scanning laser microscopy showed a defragmentation and degradation of polymeric substrates as well as microbial colonisation. Based on the results, landfill leachate is appropriate for the anaerobic biodegradation of cellulose-derived polymers; however, the process is polymer specific. [ABSTRACT FROM AUTHOR]

The use of biodegradable plastics has been proposed as an alternative to mitigate the pollution problem caused by traditional non‐biodegradable plastics. However, the relative impacts of both types of microplastics on plant community productivity and diversity is not known. Moreover, it is unclear whether soil biota can differentially mediate the impacts of biodegradable and non‐biodegradable microplastics on plant communities.In this study, we investigated the effects of biodegradable and non‐biodegradable microplastics on plant community biomass production and diversity, and whether soil biota mediate these effects. We employed a fully crossed factorial design, growing six plant communities in the presence or absence of 10 individual microplastics, and in live soil versus sterilized soil. We hypothesized that: (1) Biodegradable microplastics have a less negative effect on plant community biomass production and diversity compared to non‐biodegradable microplastics. (2) Soil biota differentially mediate the effects of biodegradable and non‐biodegradable microplastics on plant community biomass production and diversity.Statistical analyses that included all 10 microplastics yielded two main findings. First, live soil ameliorated the negative effects of biodegradable microplastics on community shoot biomass. Second, the presence of microplastics, rather than their biodegradability, significantly reduced community diversity. Separate analyses of individual microplastics suggest that these patterns were driven by specific microplastics. The biodegradable microplastic polybutylene succinate (PBS) was the main driver of the pattern observed in community shoot biomass. In contrast, the biodegradable microplastic polycaprolactone (PCL) and non‐biodegradable microplastics ethylene‐vinyl acetate (EVA) and polyvinyl chloride (PVC) were the main drivers of the pattern observed in community diversity. Further analyses excluding PBS from the global models, but including the other nine microplastics, revealed no significant differences in community shoot biomass and diversity between biodegradable and non‐biodegradable microplastics in live versus sterilized soil.Synthesis and applications. Our findings suggest that biodegradable microplastics, often considered environmentally friendly, are not necessarily less harmful than non‐biodegradable microplastics to the growth and diversity of plant communities. Some individual biodegradable microplastics, such as PBS, still pose significant ecological risks to plant community structure and productivity. However, the results also suggest that soil biota may mitigate the negative effects of some biodegradable microplastics. [ABSTRACT FROM AUTHOR]

The mounting global concern over the environmental consequences of petroleum-based plastics has prompted significant research into sustainable alternatives, with bioplastics emerging as a forerunning solution. This systematic review elucidates the multifaceted synthesis processes of bioplastics, which are derived from renewable sources such as plant starches, cellulose, and waste materials. The synthesis encompasses stages from raw material selection, pre-treatment, to the incorporation of various additives, with the aim to achieve specific properties in the resultant bioplastics. A substantial focus of this review lies in comprehensively understanding the role of additives, which serve as the pivotal agents in tailoring the mechanical and thermal characteristics of bioplastics. Additives, including cross-linking agents, plasticizers, fillers, compatibilizers, and reinforcement agents, are critically examined for their influence on attributes such as tensile strength, flexibility, thermal stability, and biodegradability. Factors such as intermolecular interactions, hydrogen bonding, and moisture content, play a determining role towards the resultant properties. The prospects for bioplastics are rapidly expanding, signalling a transformative shift in various applications ranging from eco-friendly packaging to advanced biomedical devices. This article serves as a comprehensive guide to both researchers and industry stakeholders, providing deep insights into the synthesis of bioplastics and the transformative role additives play in their functional properties. [ABSTRACT FROM AUTHOR]

The extensive use of non-biodegradable and petroleum derived polymers in industry exacerbates environmental problems associated with plastic waste accumulation and fossil resource depletion. The most promising solution to overcome this issue is the replacement of these polymers with biodegradable and bio-based polymers. In this paper, novel biocomposites were prepared from bio-based polyamide 5.6 (PA56) with the addition of olive stone powder (OSP) at varying weight concentrations by melt compounding method. The degradability of the prepared biocomposites is investigated through soil burial test, and assessed by reduction in their mechanical properties. The biodegradability of bio-based polyamide 5.6 is shown to be improved by addition of olive stone powder, and its effects on the properties of polymer matrix are elucidated. The Fourier transform infrared (FTIR) spectrum of the biocomposites indicate the successful incorporation of OSP into PA56 polymer matrix. After six-month soil burial test, scanning electron microscopy and FTIR show the degradation of PA56 through morphological and structural changes, respectively. Differential scanning calorimetry reveals the changes in the transition temperatures of the polymer matrix and an increase in crystallinity. Thermogravimetric analysis is used on the biocomposite to determine the fraction of its components, polymer and biofiller, and the results show that 2.67% (w/w) of the polyamide 5.6 is biodegraded at the end of the six-month soil burial. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impact of plastic particles on cell viability and tissue toxicity. The cells were subjected to incubation with plastic particles immobilized in agar gels, resulting in minimal cell death and cytotoxicity. Furthermore, direct exposure of various cell types to suspended plastic particles showed negligible effects on cell viability, with no observed lysis or growth inhibition. Staining techniques revealed minimal plastic particle‐induced cell death, with the majority of cells remaining viable. However, histological evaluations of mouse tissues demonstrated that the nondegradable low‐density poly(ethylene) (LDPE) groups exhibited severe irritation, characterized by an excessive presence of macrophages, neutrophils, fibrosis, fat infiltration, and increased blood vessel formation in subcutaneous tissue. In contrast, biodegradable neat poly(butylene succinate) (KRICT‐PBS) and cellulose nanocrystals/PBS nanocomposite (CNC‐PBS) groups induced minimal toxicity. Interestingly, the intravenous injection of KRICT‐PBS and CNC‐PBS degradate solutions in mice exhibited mild toxicity, suggesting no significant damage to normal kidney and liver function. [ABSTRACT FROM AUTHOR]

As plastics become more ubiquitous, their impact on the environment and on human health cannot be overlooked. Once generated, micro‐ and nano‐plastics end‐up in the environment, causing widespread health and environmental risks. This is a significant environmental problem given the minuscule sizes of microplastics, and therefore warrants further investigation. This study presents a comprehensive review of the ecotoxicology of microplastics and methods for their degradation and decomposition besides discussing the fate and transport processes, recent progress, emerging strategies, challenges and potential future directions. The authors carefully evaluate the processes through which microplastics cause harm, from molecular interactions in species, to ecological impacts, and end with advances in microplastic biodegradation. Different kinds of microplastics found in the environment include polyethylene, polystyrene, polypropylene, polyvinyl chloride, polycarbonate, polyurethane, polypropylene, and polyethylene terephthalate. Analysis of microbial and enzymatic decomposition provides several swelling mitigation strategies designed to reduce environmental threats. In‐depth investigations of microplastic ecotoxicity and biodegradation are being facilitated by interdisciplinary proposals in the areas of nanotechnology, new analytical methods, and synthetic biology. The extensive study helps understand microplastics comprehensively which in‐turn ensures informed actions to mitigate the challenge of the environmental impact of microplastics for sustainable future. [ABSTRACT FROM AUTHOR]

Plastic waste has been gradually accumulating in the environment due to rapid population growth and increasing consumer demand, posing threats to both the environment and human health. In this overview, we provide a comprehensive understanding of the degradation of plastics in real environments, such as soil, aquatic environment, landfill, and compost. Both conventional and biodegradable plastics exhibit limited degradation in real environments, except for biodegradable plastics during industrial composting with high thermophilic temperatures. Meanwhile, we also review techniques for enhanced degradation of plastics such as physical technologies (e.g., photocatalysis, mechanical degradation, and pyrolysis), chemical technologies (e.g., hydrolysis, alcoholysis, ammonia, strong oxidation, and supercritical fluids), and biotechnologies (e.g., microorganisms, microfauna, and microalgae). The future research directions for the enhancement of plastic degradation are also discussed, such as the establishment of equivalency standards, adoption of internal control techniques, the control of precise recycling of plastic products, and the ecotoxicology of their degradation products. Therefore, this review comprehensively summarizes the state of plastic degradation in real environments and proposes methods to improve plastic degradation, providing a theoretical basis for the future control and disposal of plastics. [ABSTRACT FROM AUTHOR]

The use of bioplastics is a new strategy for reducing microplastic (MP) waste caused by petroleum‐based plastics. This problem has received increased attention worldwide, leading to the development of large‐scale bioplastic plants. The large amount of MPs in aquatic and terrestrial environments and the atmosphere has raised global concern. This article delves into the profound environmental impact of the increasing use of petroleum‐based plastics, which contribute significantly to plastic waste and, as a consequence, to the increase in MPs. We conducted a comprehensive analysis to identify countries that are at the forefront of efforts to produce bioplastics to reduce MP pollution. In this article, we explain the development, degradation processes, and research trends of bioplastics derived from biological materials such as starch, chitin, chitosan, and polylactic acid (PLA). The findings pinpoint the top 10 countries demonstrating a strong commitment to reducing MP pollution through bioplastics. These nations included the United States, China, Spain, Canada, Italy, India, the United Kingdom, Malaysia, Belgium, and the Netherlands. This study underscores the technical and economic obstacles to large‐scale bioplastic production. Integr Environ Assess Manag 2024;20:1892–1911. © 2024 SETAC Key Points: Microplastics (MP) have caused concern due to their environmental effects, potential to release plastic monomers, affinity for chemical interactions, and potential to enter aquaculture and fishery production.The findings pinpoint the top 10 countries demonstrating a strong commitment to reducing MP pollution by replacing petroleum‐based plastics with bioplastics.Using bibliometric techniques, we mapped and identified the countries that were most actively engaged in shifting to bioplastic production during the period 2001–2021.This article focuses on starch‐based bioplastics used primarily in food packaging, increasing their mechanical properties by adding fibers, and extending the shelf life of food with antibacterial nanoparticles. [ABSTRACT FROM AUTHOR]

Environmental contamination by plastics poses a significant threat to both fauna and flora, manifesting in lethal and sub-lethal effects. Plastics can enter coastal and marine environments through wind and rain, with microplastics (< 5 mm; MPs) arising from the degradation of larger plastics or being manufactured for commercial use. Despite Brazil's extensive coastline, data on microplastic contamination is scarce. This study aimed to assess microplastic pollution on a beach in Rio Grande do Sul, Brazil. Samples were collected from 30 points along the high tide line, with beach sand processed through density separation and filtration. Microplastics were quantified using Nile Red stain under fluorescence microscopy and chemically identified via the µRaman technique. Results showed an average concentration of 650 MPs/kg of sediment, with higher concentrations near the Mampituba River, indicating a greater transport of plastic contaminants by the river to the coastline. The smallest particles (50–100 µm) were most abundant, and the predominant types of plastics identified were polyethylene (PE), polypropylene (PP), and polyamide (PA). This study provides the first quantification of microplastic pollution in this region, indicating that the concentration and types of microplastics are consistent with findings elsewhere in Brazil and globally. These results highlight the widespread nature of microplastic pollution and underscore the need for coordinated environmental remediation efforts. [ABSTRACT FROM AUTHOR]

Exploring microorganisms with downstream synthetic advantages in lignin valorization is an effective strategy to increase target product diversity and yield. This study ingeniously engineers the non-lignin-degrading bacterium Ralstonia eutropha H16 (also known as Cupriavidus necator H16) to convert lignin, a typically underutilized by-product of biorefinery, into valuable bioplastic polyhydroxybutyrate (PHB). The aromatic metabolism capacities of R. eutropha H16 for different lignin-derived aromatics (LDAs) are systematically characterized and complemented by integrating robust functional modules including O-demethylation, aromatic aldehyde metabolism and the mitigation of by-product inhibition. A pivotal discovery is the regulatory element PcaQ, which is highly responsive to the aromatic hub metabolite protocatechuic acid during lignin degradation. Based on the computer-aided design of PcaQ, we develop a hub metabolite-based autoregulation (HMA) system. This system can control the functional genes expression in response to heterologous LDAs and enhance metabolism efficiency. Multi-module genome integration and directed evolution further fortify the strain's stability and lignin conversion capacities, leading to PHB production titer of 2.38 g/L using heterologous LDAs as sole carbon source. This work not only marks a leap in bioplastic production from lignin components but also provides a strategy to redesign the non-LDAs-degrading microbes for efficient lignin valorization. One challenge in lignin valorization is that microorganisms possessing downstream metabolic advantages are unable to convert lignin. Here, the authors engineer the non-lignin-degrading bacterium Ralstonia eutropha to efficiently convert lignin into polyhydroxybutyrate using a self-enhanced autoregulation system. [ABSTRACT FROM AUTHOR]

To access degradable polyolefin plastic, non‐alternating copolymerization of ethylene (E) and carbon monoxide (CO) for producing polyethylene (PE) with in‐chain ketones is particularly appealing; however, it still presents significant challenges such as molecular weight modulation (hydrogen response) and chain endgroup control (functional terminal). In this study, we achieved hydrogen‐controlled E/CO non‐alternating copolymerization using late transition metal catalysts. This process results in linear PEs containing the desired non‐alternating in‐chain keto groups (1.0–9.3 mol %) and with tunable molecular weights ranging from 43 to 195 kDa. In this reaction, H2 serves as a chain transfer agent, modulating the polymer's molecular weight, forming unique aldehyde endgroups and eliminating usual olefinic endgroups; CO undergoes non‐alternating insertion into the PE chain, resulting in a strictly non‐alternating structure (>99 %) for the keto‐PE. The dispersed incorporation of in‐chain keto groups retains bulk properties of PE and makes PE susceptible to photodegradation, which produces significantly lower molecular weight polymers and oligomers with unambiguous vinyl and acetyl terminals. [ABSTRACT FROM AUTHOR]

Biodegradable polymers are gaining attention as alternatives to non‐biodegradable plastics to address environmental issues. With the rising global demand for plastic products, the development of non‐toxic, biodegradable plastics is a significant topic of research. Aliphatic polyester, the most common biodegradable polyester, is notable for its semi‐crystalline structure and can be synthesized from fossil fuels, microbial fermentation, and plants. Due to great properties like being lightweight, biodegradable, biocompatible, and non‐toxic, aliphatic polyesters are used in packaging, medical, agricultural, wearable devices, sensors, and textile applications. The biodegradation rate, crucial for biodegradable polymers, is discussed in this review as it is influenced by their structural properties and environmental conditions. This review discusses currently available biodegradable polyesters, their emerging applications, and the challenges in their commercialization. As research in this area grows, this review emphasizes the innovation in biodegradable aliphatic polyesters and their role in advancing environmental sustainability. [ABSTRACT FROM AUTHOR]

As environmental problems increase, disposable products are being replaced and recommended with materials with a low environmental load when it discarded. So the demand for bioplastics for building a sustainable society is increasing. This study focuses mainly on the applicability of biodegradable plastics and rosin maleic resin (RMR, DX‐250) blends with potential use in eco‐friendly hot‐melt adhesives (HMA). Poly (butylene adipate‐co‐terephthalate) (PBAT), which has high dimensional stability owing to low crystallinity, is used as the main polymer of the HMA. And rosin maleic resin, which is effective for increasing adhesive properties and compatibility as a tackifier. The HMA based on PBAT and RMR blends are prepared via melt‐blend extrusion. Compatibility and wettability are increased under the influence of RMR, and adhesion properties are improved, compared to that of PBAT. In addition, as confirmed polarizing microscope (POM), the addition of RMR leads to a decrease in crystallinity, which can be expected to be effective for biodegradation. This result PBAT/RMR 7/3 blend significantly enhances the adhesion strength of PBAT from 1.8 to 7.3 MPa. Therefore, PBAT with the blends containing 30 wt.% of RMR has considerable potential application in the HMA field. [ABSTRACT FROM AUTHOR]

Medical plastic-appliance-based healthcare services, especially in dentistry, generate tremendous amounts of plastic waste. Given the physiological features of our mouth, it is desirable to substitute dental care plastics with viscoelastic and antimicrobial bioplastics. Herein, we develop a medical-grade and sustainable bioplastic that is viscoelastic enough to align the tooth positions, resists microbial contamination, and exhibits recyclable life cycles. In particular, we devise a molecular template involving entanglement-inducing and antimicrobial groups and prepare a silk fibroin-based dental care bioplastic. The generated compactly entangled structure endows great flexibility, toughness, and viscoelasticity. Therefore, a satisfactory orthodontic outcome is accomplished, as demonstrated by the progressive alignment of male rabbit incisors within the 2.5 mm range. Moreover, the prepared bioplastic exhibits resistance to pathogenic colonization of intraoral microbes such as Streptococcaceae and Veillonellaceae. Because the disentanglement of entangled domains enables selective separation and extraction of the components, the bioplastic can be recycled into a mechanically identical one. The proposed medical-grade and sustainable bioplastic could potentially contribute to a green healthcare future. Medical plastic-appliance-based healthcare services, especially in dentistry, generate large amounts of plastic waste. Here, the authors address this issue by developing a medical-grade and sustainable bioplastic that is viscoelastic enough to align the tooth positions, resists microbial contamination, and exhibits recyclable life cycles. [ABSTRACT FROM AUTHOR]

As one of the mainstream biodegradable materials, poly(butylene adipate-co-terephthalate) (PBAT) foams offer a sustainable alternative to traditional plastic foams, effectively reducing environmental pollution. However, the high cost and poor mechanical performance of PBAT foams impede their practical application. Herein, the glycidyl methacrylate-grafted biomass lignin (GML) was used to produce a PBAT/GML composite foam with good foaming performance and mechanical properties at high lignin-filling amounts by twin-screw melting free radical polymerization and supercritical CO2 foaming process. The compatibility of GML in the PBAT matrix was improved due to the formation of ester bonds in modified lignin, endowing the PBAT/GML (PGML) composite foam with exceptional foaming performance. Additionally, the mechanical properties of PGML composite foam were remarkably enhanced due to the introduction of the abundant aromatic structures of GML and the construction of a stable covalent crosslinking network. The compressive strengths and compression modulus of the PGML foam were improved by 2.53 times and 2.47 times, while its bending strength and bending modulus were improved by 1.27 times and 3.92 times compared to the neat PBAT. This research affords a new strategy for developing low-cost biodegradable biomass PBAT/lignin composite foam materials with good foaming performance and mechanical properties. [ABSTRACT FROM AUTHOR]

Biodegradable polymers are getting attention as renewable alternatives to petroleum-based plastics due to their environmental benefits. However, improving their physical properties remains challenging. In this work, biodegradable biopolymers (PVA-PCD) were fabricated by chemically crosslinking petroleum-based polyvinyl alcohol (PVA) with biomass-derived cardanol-based polyols (PCD). Biopolymers were characterized using various techniques, including Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and swelling tests. Cardanol, the raw material, was converted into polyols via epoxidation followed by hydroxylation. FT-IR analysis confirmed that PVA-PCD biopolymers were crosslinked between the hydroxyl groups of PVA and PCD and the aldehydes of crosslinker glutaraldehyde (GLU), accompanied by the formation of acetal groups with ether bridges. XRD showed that the crystallinity of crosslinked polymers decreased, indicating that crosslinking occurs disorderly. TGA exhibited that GLU significantly improved the thermal stabilities of PVA and PCD-PVA polymers, as evidenced by increased decomposition temperatures. On the other hand, the effect of PVA/PCD ratios was minor on biopolymers' thermal stabilities. Swelling tests revealed that increased crosslinking density decreased the swelling ratio, suggesting that PVA-PCD biopolymers become more hydrophobic with high brittleness, high strength, and low swelling capacity. In summary, this study demonstrates that PVA-PCD biopolymers fabricated from biomass-derived materials have potential for various applications, such as biodegradable materials and sustainable packaging. [ABSTRACT FROM AUTHOR]

In this study, polylactic acid (PLA) is compounded with cottonseed protein concentrate (CPC) by melt blending under the compatibilization of maleic anhydride (MA), and then hot‐pressed to prepare PLA/CPC composite bioplastics. The attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopy showed that high temperature and compatibilizer induced the protein secondary structure to transition. CPC can be used as a heterogeneous PLA nucleating agent, effectively accelerating PLA crystallization, which is characterized by polarization optical microscopy (POM), synchrotron radiation wide‐angle X‐ray scattering (WAXS) and differential scanning calorimetry (DSC). The highest crystallinity of the PLA/CPC10 composite is 8.9% higher than that of neat PLA. The unfolding of the protein secondary structure is likely to promote an orderly arrangement of PLA crystals, showing strong binding forces between them. Moreover, the CPC/PLA interfacial compatibility is improved by the addition of a small amount of maleic anhydride. The increased crystallinity and interfacial compatibility contribute to the improved mechanical properties, water resistance, and thermal stability of the bioplastics. Environmentally friendly plastic handicrafts (e.g., commemorative emblems, flower pots, ornaments, etc.) can be fabricated using these biocomposites for future value‐added applications. [ABSTRACT FROM AUTHOR]

Food packaging, which is typically made of paper/cardboard, glass, metal, and plastic, is essential for protecting and preserving food. However, the impact of conventional food packaging and especially the predominant use of plastics, due to their versatility and low cost, bring serious environmental and health problems such as pollution by micro and nanoplastics. In response to these challenges, biotechnology emerges as a new way for improving packaging by providing biopolymers as sustainable alternatives. In this context, bacterial cellulose (BC), a biodegradable and biocompatible material produced by bacteria, stands out for its mechanical resistance, food preservation capacity, and rapid degradation and is a promising solution for replacing plastics. However, despite its advantages, large-scale application still encounters technical and economic challenges. These include high costs compared to when conventional materials are used, difficulties in standardizing membrane production through microbial methods, and challenges in optimizing cultivation and production processes, so further studies are necessary to ensure food safety and industrial viability. Thus, this review provides an overview of the impacts of conventional packaging. It discusses the development of biodegradable packaging, highlighting BC as a promising biopolymer. Additionally, it explores biotechnological techniques for the development of innovative packaging through structural modifications of BC, as well as ways to optimize its production process. The study also emphasizes the importance of these solutions in promoting a circular economy within the food industry and reducing its environmental impact. [ABSTRACT FROM AUTHOR]

This study aims to enhance the properties of biodegradable plastics by blending poly(lactic acid) (PLA) as well as poly(butylene succinate) (PBS) with silicon carbide (SiC). SiC content was varied from 10 to 40 phr using an internal mixer, maintaining a 90/10 wt% ratio of PLA/PBS as the matrix. The investigation covered mechanical, thermal properties, chemical structure, and composite morphology. The morphological analysis confirmed even dispersion of SiC within the PLA/PBS matrix, possibly due to improved compatibility via a silane coupling treatment. This resulted in the maximum Young's modulus and impact strength with 40 phr SiC, showing a 40% and 76% enhancement, respectively, compared to pure PLA. Concerning thermal properties, SiC addition influenced the mobility of PLA/PBS molecular chains and crystalline structure, leading to an increase in Tg with higher SiC fractions. However, ΔHm of PLA, PBS, and Xc,PLA decreased, which corresponds to reduced viscosity in the PLA/PBS blend and increased mobility with higher SiC content, as indicated by the elevated MFI value. Highlights: Young's modulus increased by 40% and impact strength by 76% than pure PLA.Even SiC dispersion in PLA/PBS, possibly aided by silane coupling.SiC alters chain mobility, boosts crystalline structure, raising Tg.ΔHm and Xc,PLA reduced, suggests reduced viscosity in PLA/PBS at more SiC.Elevated MFI value shows increased chain mobility in PLA/PBS blend at more SiC. [ABSTRACT FROM AUTHOR]

Bio‐based polymers may present a sustainable, circular way to reduce the environmental impact of plastics because they are produced from biomass that absorbs CO2 during its growth. However, sourcing (type of biomass used and cultivation location), production, and end‐of‐life affect the environmental impact of bio‐based plastics. We assessed the effect of sourcing and end‐of‐life options on the environmental impact of bio‐based high‐density polyethylene (bio‐HDPE) in 31 sourcing scenarios and five end‐of‐life options. Our study found that careful consideration of biomass sourcing (biomass type and production location) and end‐of‐life is needed to optimize the environmental impact of bio‐based plastics. If these aspects are not considered, the environmental impact of bio‐HDPE may exceed that of its petrochemical‐based counterpart. The direct availability of fermentable sugars indicated a lower environmental impact. The production location affected the resources needed for biomass cultivation and the environmental impact of processing due to the energy mix. Recently published guidelines do not allow biogenic carbon to be accounted for during the production stage, but only upon the incineration of the plastic. Our results show that this way of attributing biogenic carbon results in an apparent disadvantage for bio‐based plastics compared to petrochemical‐based plastics. Furthermore, it disadvantaged mechanical recycling of bio‐based plastics compared to incineration, a result out of line with circular economy principles. [ABSTRACT FROM AUTHOR]

As a model of a chemical upcycling process, we have developed a single-metal homogeneous catalytic system to break down persistent polyethylene waste into valuable chemical intermediates. This could ultimately be used to produce important chemical products, including environmentally friendly, biodegradable plastics. In the first step, a slow pyrolysis of polyolefin waste yields oils, containing long-chain olefins as the major components. Then, for the next transformation step, tailored bicyclic (alkyl)(amino)carbene (BICAAC)-Ru olefin metathesis catalysts were used in combination with an alkene isomerization catalyst (RuHCl(CO)(PPh3)3) for the transformation of the pyrolysis oil to propylene via isomerization-metathesis (ISOMET) reaction in ethylene atmosphere. Eventually, translation of the highly efficient single-metal catalyst system enabled ISOMET reaction to a 900 mL reactor setup and repetitive batch experiments could prove the long-term stability of the catalyst system and the highest total turnover number (tTON = 2788 mol propylene per mol olefin metathesis catalyst) reported so far using post-consumer polyethylene waste feedstock. [ABSTRACT FROM AUTHOR]

Bioplastics were produced by mixing starch with sorbitol, glacial acetic acid, and carboxymethyl cellulose (CMC) during the manufacturing process. The physical characteristics of the bioplastics were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Tensile strength, elongation, and Young's modulus tests were utilized to assess the mechanical characteristics of bioplastics. The bioplastic with the highest tensile strength was BP3 (7.03 ± 0.34 N/mm2), whereas BP0 had a tensile strength of 1.57 ± 0.11 N/m2. The addition of CMC increased the viscosity of the solution and, consequently, the strength of the bioplastic. The range of bioplastic hydrophobicity was ~ 128.32–323.74%. FTIR and XPS test results indicated that the physical mixing utilized during synthesis did not result in the addition of functional groups other than the native functional groups of the substances since no chemical reaction occurred. The thermal behavior investigation revealed that increasing the amount of CMC added to TPS can increase the presence of O–H functional groups in bioplastics, contributing to an increase in the glass transition temperature. Furthermore, both bioplastics broke down at ~ 250 °C. [ABSTRACT FROM AUTHOR]

The widespread use of traditional petroleum‐based plastics is causing significant environmental pollution for example microplastics issues, due to its non‐biodegradability. Poly (lactic acid) (PLA) as a representative biodegradable polymer is a promising candidate to replace petroleum‐based plastics in some fields of disposable packaging materials and tableware. In this work, in order to improve the poor crystallization, mechanical and heat resistance performances of PLA, styrene–acrylonitrile‐glycidyl methacrylate (SAG) as a chain extender and octamethylenedicarboxylic dibenzoylhydrazide (ST‐NAB3) as a heterogeneous nucleating agent (HNA) were added simultaneously into PLA matrix. The chain‐extended PLA (CPLA) with branch structures had smaller crystal sizes and higher crystal density, compared with those of pure PLA. In addition, thanks to the nucleation effect of ST‐NAB3 and the development of "shish‐kebab", this tendency became more pronounced in CPLA/HNA systems. It was worth mentioning that, CPLA with the ST‐NAB3 content of 1 wt% (CPLA‐1) possessed the highest crystallinity of 43.6%. Meanwhile, CPLA‐1 had the best impact strength and heat deformation temperature of 38.9 kJ/m2 and 91.3°C respectively, which had increased by 11.3 kJ/m2 and 32.4°C contrast to pure PLA. On the whole, this study proposed a simple and effective method, which provided a new possibility for PLA modification research. [ABSTRACT FROM AUTHOR]

Wastewater treatment facilities can filter out some plastics before they reach the open environment, yet microplastics often persist throughout these systems. As they age, microplastics in wastewater may both leach and sorb pollutants and fragment to provide an increased surface area for bacterial attachment and conjugation, possibly impacting antimicrobial resistance (AMR) traits. Despite this, little is known about the effects of persistent plastic pollution on microbial functioning. To address this knowledge gap, we deployed five different artificially weathered plastic types and a glass control into the final maturation pond of a municipal wastewater treatment plant in Ōtautahi-Christchurch, Aotearoa/New Zealand. We sampled the plastic-associated biofilms (plastisphere) at 2, 6, 26, and 52 weeks, along with the ambient pond water, at three different depths (20, 40, and 60 cm from the pond water surface). We investigated the changes in plastisphere microbial diversity and functional potential through metagenomic sequencing. Bacterial 16S ribosomal RNA genes composition did not vary among plastic types and glass controls (P = 0.997) but varied among sampling times [permutational multivariate analysis of variance (PERMANOVA), P = 0.001] and depths (PERMANOVA, P = 0.011). Overall, there was no polymer-substrate specificity evident in the total composition of genes (PERMANOVA, P = 0.67), but sampling time (PERMANOVA, P = 0.002) and depth were significant factors (PERMANOVA, P = 0.001). The plastisphere housed diverse AMR gene families, potentially influenced by biofilm-meditated conjugation. The plastisphere also harbored an increased abundance of genes associated with the biodegradation of nylon, or nylon-associated substances, including nylon oligomer-degrading enzymes and hydrolases. IMPORTANCE Plastic pollution is pervasive and ubiquitous. Occurrences of plastics causing entanglement or ingestion, the leaching of toxic additives and persistent organic pollutants from environmental plastics, and their consequences for marine macrofauna are widely reported. However, little is known about the effects of persistent plastic pollution on microbial functioning. Shotgun metagenomics sequencing provides us with the necessary tools to examine broad-scale community functioning to further investigate how plastics influence microbial communities. This study provides insight into the functional consequence of continued exposure to waste plastic by comparing the prokaryotic functional potential of biofilms on five types of plastic [linear low-density polyethylene (LLDPE), nylon-6, polyethylene terephthalate, polylactic acid, and oxygendegradable LLDPE], glass, and ambient pond water over 12 months and at different depths (20, 40, and 60 cm) within a tertiary maturation pond of a municipal wastewater treatment plant. [ABSTRACT FROM AUTHOR]

Petroleum‐derived plastics are harmful to ecosystems because they are not decomposed in the natural environment. Therefore, the replacement of petroleum‐derived plastics with biodegradable plastics has attracted considerable attention. UV‐barrier films in the agricultural and packaging fields are mainly composed of petroleum‐derived plastics, which have a negative impact on the ecosystem when they leak into the environment. Thermoplastic starch (TPS) is an inexpensive and sustainable biodegradable plastic that has recently attracted considerable attention. In this study, the addition of UV barrier properties and remolding ability to TPS for replacing petroleum‐derived UV barrier films are investigated. Also, a biodegradable polyester coating is studied to improve the water resistance of the prepared UV‐barrier TPS (U‐TPS). To prepare U‐TPS, a conjugated enamine structure is formed by reacting starch acetoacetate with diamine monomers during melt kneading. U‐TPS exhibits high UV barrier properties across the UV regions (200–400 nm) owing to the presence of acetoacetyl groups and enamines. These results indicate the possibility of increasing the utilization of TPS in agriculture and as a packaging material. [ABSTRACT FROM AUTHOR]

The use of fossil-based plastics in food packaging poses a serious environmental concern. Pectin, a natural biodegradable polymer, offers a potential solution for environmentally friendly and sustainable food packaging to replace fossil-based plastics. This article reviews the applications of pectin in active and intelligent packaging and analyzes the latest research trends. Bibliometric analysis was used to review the existing literature on pectin in food packaging. Data were collected from the Scopus database, which covers research on film manufacturing and pectin-based coating. Pectin-based active packaging contains antimicrobial and antioxidant compounds such as ascorbic acid and essential oils, which effectively prevent bacterial growth while absorbing oxygen and water vapor. In contrast, pectin-based intelligent packaging allows real-time monitoring of food quality through integrated color-changing indicators, eliminating the need for open packaging. Research trends have shown a significant increase in publications on pectin-based packaging, reflecting the growing interest in sustainable packaging solutions. With a focus on innovation and sustainability, pectin can replace conventional plastics and provide safer and more durable packaging solutions, thereby supporting global efforts to reduce the environmental impact of plastic waste. [ABSTRACT FROM AUTHOR]

Few studies have investigated the biodegradation of microplastics in marine environments. Microorganisms that can degrade microplastics in high-salinity conditions are sought after. Therefore, we aimed to isolate a halotolerant poly(ε-caprolactone) (PCL)-degrading bacterium for applications in biotechnology. The bacterium isolated from seaside soil was identified as Bacillus gibsonii via phylogenetic analysis based on 16S rRNA gene sequences and designated as KRICT-1. We tested whether the KRICT-1 strain showed halotolerance by determining the sodium chloride (NaCl) tolerance at various concentrations. The KRICT-1 strain showed growth at up to 10% NaCl on Luria–Bertani (LB) medium agar plates and 10% NaCl in liquid LB medium, indicating that KRICT-1 can grow and produce a PCL-depolymerizing enzyme under high-salt conditions. The KRICT-1 strain could depolymerize PCL with a PCL film weight loss of 2.82% at up to 10% NaCl concentration after cultivation of 7 weeks. KRICT-1 is the first strain of B. gibsonii which shows PCL-depolymerizing activity. Scanning electron microscopy and water contact angle results confirmed the degradation of PCL by the KRICT-1 strain. The extracellular enzyme produced by the KRICT-1 strain was stable over a wide range of temperatures (15–40 °C) and pH (7.0–9.5). This halotolerant PCL-degrading bacterium can be used in the degradation of biodegradable plastics present in saline soils, saline water, and wastewater. [ABSTRACT FROM AUTHOR]