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Phosphorus to an optimum extent is an essential nutrient for all living organisms and its scarcity may cause food security, and environmental preservation issues vis-à-vis agroeconomic hurdles. Undesirably excess phosphorus intensifies the eutrophication problem in non-marine water bodies and disrupts the natural nutrient balance of the ecosystem. To overcome such dichotomy, biodegradable polymer–based adsorbents have emerged as a cost-effective and implementable approach in striking a "desired optimum-undesired excess" balance pertaining to phosphate in a sustainable manner. So far, the reports on adopting such adsorbent-approach for wastewater remediation remained largely scattered, unstructured, and poorly correlated. In this background, the contextual review comprehensively discusses the current state-of-the-art in utilizing biodegradable polymeric frameworks as an adsorbent system for phosphate removal and its efficient recovery from the aquatic ecosystem, while highlighting their characteristics-specific functional efficiency vis-à-vis easiness of synthetic and commercial viability. The overview further delves into the sources and environmental ramifications of excessive phosphorus in water bodies and associated mechanistic pathways of phosphorus removal via adsorption, precipitation, and membrane filtration enabled by biodegradable (natural and synthetic) polymeric substrates. Finally, functionality optimization, degradability tuning, and adsorption selectivity of biodegradable polymers are highlighted, while aiming to strike a balance in "removal-recovery-reuse" dynamics of phosphate. Thus, the current review not only paves the way for future exploration of biodegradable polymers in sustainable cost-effective adsorbents for phosphorus removal but also can serve as a guide for researchers dealing with this critical issue. [ABSTRACT FROM AUTHOR]

Manifold aspects, such as the booming market for superior quality food items with increased shelf life and the escalating concern to mitigate plastic trash due to plastic packaging have motivated researchers and food industrialists to explore sustainable eco-friendly packaging solutions extensively. Biodegradable polymers are being rigorously investigated to replace conventional plastics that are toxic, non-biodegradable, and detrimental to the marine ecosystem. The scientific methodology for the prudent selection of biodegradable polymer among the frequently used biopolymers for food packaging is being reported here. The data were extracted from the available literature. A hybrid multi-criteria decision-making framework has been developed to address the problem of material selection owing to the multiple conflicting criteria involved. Assignment of equal weights to primary criteria was selected to establish the criteria weights. Different decision-making techniques (weighted sum method (WSM), weighted product method (WPM), weighted aggregated sum product assessment method (WASPAS), and technique for order of preference by similarity to ideal solution (TOPSIS)) were used for the comparative analysis. Thereon, the different ranks obtained for each alternative were aggregated using the degree of membership technique. The robustness of the solution was checked using sensitivity analysis which was conducted by varying weights of importance using the entropy method, the CRITIC method, and the equal weights to secondary criteria. The analysis reported polylactic acid (PLA) as the most reliable polymer for food packaging applications. The sensitivity analysis concluded that the solution was without prejudice, and water vapor permeation rating was the most critical decision criterion in deciding the optimal polymer. [ABSTRACT FROM AUTHOR]

The pervasive presence of microplastics within river ecosystems has a profound and often underestimated detrimental impact. These minuscule yet persistent particles have infiltrated diverse biological habitats, making their detrimental effects on aquatic life increasingly concerning worldwide. The ability of microplastics to accumulate within aquatic organisms further exacerbates this concern. Consequently, the monitoring of microplastic pollution in surface water environments has emerged as a crucial endeavour, offering invaluable insights into the extent of this ecological threat. This study delved into the contamination levels of microplastics within two bivalve species, Perna viridis and Villorita cyprinoides, along the Chandragiri River in Kerala and Karnataka, South-West India, spanning eight distinct locations. The investigation yielded a significant discovery, with a total of 667 microplastic particles extracted from 288 individuals. On average, each individual bivalve harboured approximately 2.31 ± 0.93 microplastic items. Notably, these microplastic particles exhibited a wide range of morphological characteristics, underscoring their diverse origins and pathways into the ecosystem. Furthermore, five polymer types of microplastics were unequivocally confirmed through FTIR-ATR analysis, shedding light on the types of plastics that pose a threat to the riverine ecosystem. The findings of this study contribute to a growing body of evidence highlighting the global threat of microplastic pollution, urging international collaboration and innovative solutions to prevent further contamination and remediate existing microplastic burdens in aquatic environments. Highlights: • Microplastic contamination is a major concern in river ecosystems. • Microplastic in two bivalve species were characterized at Chandragiri River India. • The microplastics had diverse shapes and were composed of five different polymers. • This study emphasizes the need to tackle river microplastic pollution. [ABSTRACT FROM AUTHOR]

Development of biodegradable polymer composites with superior properties is a promising way to mitigate plastic pollution. In the present study, poly(L-lactic acid) (PLLA, as the bio-based matrix) and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized cellulose nanofiber (TOCNF, as the bio-based filler) were combined by Pickering emulsion method to prepare PLLA/TOCNF composite microspheres. The yarn-ball-like microspheres had diameters of approximately 0.5–8.0 μm. The composite microspheres were hot-pressed to prepare PLLA/TOCNF composite films with layered structures. The composite films with 7.5% and 10% TOCNF addition amounts (PT7.5 and PT10 films) further underwent cold crystallization to increase the crystallinity of the PLLA matrices to 28–30%. The neat PLLA film exhibited Young's modulus (YM) of 2.8 GPa, contact angle (CA) of 69.7°, and coefficient of thermal expansion (CTE) of 12923 ppm K−1. The cold-crystallized PT7.5 (C-PT7.5) film exhibited superior properties such as YM of 4.0 GPa, CA of 85.0°, and CTE of 239 ppm K−1. The parameters were 142.9%, 122.0%, and 1.8% of those of the PLLA film, respectively. Hence, the properties of the PLLA film can be simultaneously significantly improved by adding the TOCNFs and cold crystallization, enhancing the potential of the PLA-based materials for packaging applications. [ABSTRACT FROM AUTHOR]

Polyhydroxybutyrate (PHB), a sustainable biodegradable polymer with various industrial and medical applications, produced by microorganisms is a good replacement of conventional plastics, a major environmental contaminant. The aim of this study is to isolate and evaluate the PHB producing ability of the microorganisms isolated from various soil sources. By employing different staining methods such as Sudan black B, Nile red and Nile blue A, the primary screening of PHB producers was performed. Among the 104 soil isolates, four strains (SNA1, SNA2, SNA3 and SNA4) exhibited positive results for all the staining tests. On further studies, among these the strain SNA2 produced highest level of PHB (64%) from its whole cell dry weight, while glucose (20 g/L) and urea (2 g/L) were used as the carbon and nitrogen sources respectively at pH 7, 30 °C after 48 h of incubation. The Fourier transform infrared spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance (1H NMR) results confirmed that the polymer produced was PHB. The 16S rRNA sequencing revealed results that the strain SNA2 was Klebsiella pneumonia. The production ability of the novel Klebsiella pneumonia SNA2 was further enhanced by optimizing various process parameters such as carbon and nitrogen sources, pH, temperature and incubation period. The process optimization resulted in enhanced PHB synthesis (up to 75%) with Xylose as carbon source and urea as the nitrogen source with pH 7.5 at 35 °C after 36 h. In addition, an attempt to produce a biofilm from the extracted polymer was also successful. Thus, the novel bacterial isolate Klebsiella pneumonia SNA2 was proved to be a challenging host for the synthesis of PHB and the scale up studies are under progress. Whole genome sequencing, identification of pathway genes and metabolic engineering strategies were believed to enhance the PHB synthesis further to the industrial scale. [ABSTRACT FROM AUTHOR]

Contamination by microplastics (MPs) has been recorded in various environments and organisms around the world. The objective of this study was to investigate the occurrence of MPs in two species of Siluriformes fishes Pterygoplichthys pardalis and Hoplosternum littorale considering the sex and different body parts of fish captured in Amazon floodplain areas, which are marketed and consumed in the Municipality of Itacoatiara, Amazonas, Brazil. One hundred and fifty individuals of each fish species were analyzed for microplastics. Of these, 252 individuals were found to contain MPs: 127 (85%) P. pardalis and 125 (83%) H. littorale. The fish were contaminated with 683 MP particles, ranging from 1 to 43 MP particles/individual, with an average of 2.71 ± 3.2 MP particles/individual P. pardalis and H. littorale. Comparison of MP occurrence and particle size between species, sex, and body part found no significant difference. Fiber-shaped and blue-colored MPs were the most abundant in both P. pardalis (80% and 85.5%, respectively) and H. littorale (92% and 85%, respectively). The particles were identified as polyethylene terephthalate and polystyrene. The results indicate MP contamination in P. pardalis and H. littorale catfish, which are widely consumed by Amazonian riverside communities. These species are often cooked whole (including the viscera) becoming a direct route of microplastic contamination to humans. [ABSTRACT FROM AUTHOR]

The potential effects of microplastic particle exposure on environmental organisms has sparked intense research activities. Various studies have been conducted, however on a limited set of mostly pristine polymer materials. In parallel to the ongoing research activities, it is discussed to include non-natural polymers into the registration process under REACH. Currently, non-natural polymers are exempted from registration, based on the general assumption of being non-hazardous due to their high molecular weight. In addition, the extensive number of polymers exceeding the registration capacities was mentioned as a reason for exemption. Hence, relevant polymers requiring a registration shall be selected according to specific criteria that help to identify those with a concern for hazardous effects. In the line of these developments we here present the results of a systematic ecotoxicity testing of 16 microplastic particles of different polymer composition, part of which are micronized polymer powders used in 3D printing (intentionally produced primary microplastic, losing particle shape by the 3D printing). All polymer materials were systematically varied and extensively characterised with regard to their properties (e.g. particle size, cross-linking, molar mass distribution, end groups, reactivity). Most of the polymers exerted toxicity in 48 h acute Daphnia magna immobilisation assay and 72 h chronic Raphidocelis subcapitata growth inhibition assay, except one PA and one HDPE material showing toxicity in D. magna, and one HDPE material showing toxicity in green algae. From these results we conclude that none of the microplastic particles studied here, independent of their polymer properties, give raise to concern for hazardous effects. [ABSTRACT FROM AUTHOR]

Biodegradable polymers are an important part of the solution toolbox to achieve circularity in the plastic economy and overcome negative impacts of a linear plastic economy. Biodegradable polymers need to excel not only on a mechanical performance level in the application to fulfill their function during the use phase but also on a biodegradation performance level after use. The biodegradation performance is tailored to the application and the receiving environment of the polymer product after use, which can be both engineered systems (e.g., compost, anaerobic digestors, wastewater treatment plants) and natural systems (e.g., soils, freshwater, or marine environments). This chapter addresses key aspects of polymer biodegradability and biodegradation in both natural and engineered systems with the goal to advance a more holistic view on the topic and, thereby, provide guidance for all stakeholders working on developing, testing, and regulating biodegradable polymers. These aspects include definitions of biodegradability and biodegradation, elucidating polymer- and environmental factors that control the biodegradation process, a discussion of the analytical chemistry of polymer biodegradation, polymer biodegradability testing and certification, as well as a brief overview of research needs. In accordance with the diverse backgrounds of the authors of the chapter, this chapter targets all stakeholder groups from academics to industry and regulators. [ABSTRACT FROM AUTHOR]

In the course of the past two decades, biodegradable polymers have established to serve in form of compostable or soil-biodegradable items as sustainable alternatives to standard plastics in applications where their property of biodegradability adds value. BASF has been a pioneer in this field of action with their commercially available products ecoflex® and ecovio®. Based on continuous research and development at the edge between polymer chemistry and microbiology, not only new developments were realized in the recent past but also a deep understanding about biodegradation under various conditions could be generated. This chapter provides an up-to-date picture about the chemistry and biodegradation, about processing, applications as well as the sustainability contribution of ecoflex® and ecovio®. [ABSTRACT FROM AUTHOR]

Polyacrylic acid is a biocompatible and biodegradable polymer that has been widely investigated for use in drug delivery. It has a number of properties that make polyacrylic acid a promising material for various applications, including ability to form hydrogels, mucoadhesive properties, and stimuli-responsive behavior. Polyacrylic acid hydrogels can be used to deliver drugs to a variety of tissues and organs. They can be prepared in a variety of forms, including injectable gels, films, and tablets. These hydrogels can be loaded with a variety of drugs, including proteins, peptides, and small molecules. The mucoadhesive properties of polyacrylic acid make it a good choice for delivering drugs to the eye, nose, and skin. Polyacrylic acid can adhere to these mucosal surfaces, which can help to prolong the drug's release and improve its bioavailability. The stimuli-responsive behavior of polyacrylic acid can be used to develop drug delivery systems that release drugs in response to specific stimuli, such as changes in pH, temperature, or ionic strength. This can be used to control the release of drugs in a way that is tailored to the specific needs of the patient. The research on the use of polyacrylic acid in drug delivery is ongoing. As our understanding of its properties and behavior improves, we can expect to see even more innovative and effective drug delivery systems developed in the future. [ABSTRACT FROM AUTHOR]

Quantification and characterization of microplastics, synthetic polymers less than 5 mm in diameter, requires extraction methods that can reduce non-plastic debris without loss or alteration of the polymers. Nitric acid has been used to extract plastic particles from zooplankton and other biota because it completely digests tissue and exoskeletons, thus reducing interferences. While the impact of acid digestion protocols on several polymers has been demonstrated, advice for quantifying microplastic and interpreting their spectra following nitric acid digestion is lacking. Fourier transform infrared (FTIR) and/or Raman spectroscopy was performed on plastics from > 50 common consumer products (including a variety of textiles) pre- and post-nitric acid treatment. The percent match and assigned polymer were tabulated to compare the accuracy of spectral identification before and after nitric acid digestion via two open spectral analysis software. Nylon-66, polyoxymethylene, polyurethane, polyisoprene, nitrile rubber, and polymethyl methacrylate had ≥ 90% mass loss in nitric acid. Other less-impacted polymers changed color, morphology, and/or size following digestion. Thus, using nitric acid digestion for microplastic extraction can impact our understanding of the particle sizes and morphologies ingested in situ. Spectral analysis results were compiled to understand how often (1) the best-hit matches were correct (30–60% of spectra), (2) the best-hit matches exceeding the (arbitrary) threshold of 65% match were correct (53–78% of spectra), and (3) the best-hit matches for anthropogenic polymers were incorrectly identified as natural polymers (12–15% of spectra). Based on these results, advice is provided on how nitric acid digestion can impact microplastics as well as spectral interpretation. [ABSTRACT FROM AUTHOR]

Biodegradable polymers have emerged as fascinating materials due to their non-toxicity, environmentally benign nature and good mechanical strength. The toxic effects of non-biodegradable plastics paved way for the development of sustainable and biodegradable polymers. The engineering of biodegradable polymers employing various strategies like radical ring opening polymerization, enzymatic ring opening polymerization, anionic ring opening polymerization, photo-initiated radical polymerization, chemoenzymatic method, enzymatic polymerization, ring opening polymerization and coordinative ring opening polymerization have been discussed in this review. The application of biodegradable polymeric nanoparticles in the biomedical field and cosmetic industry is considered to be an emerging field of interest. However, this review mainly highlights the applications of selected biodegradable polymers like polylactic acid, poly(ε-caprolactone), polyethylene glycol, polyhydroxyalkanoates, poly(lactide-co-glycolide) and polytrimethyl carbonate in various fields like agriculture, biomedical, biosensing, food packaging, automobiles, wastewater treatment, textile and hygiene, cosmetics and electronic devices. [ABSTRACT FROM AUTHOR]

Given the greater global awareness of environmental impacts of plastics and the need to develop alternative materials from renewable natural resources, there has been an increasing drive over recent years to develop biobased and biodegradable composites, especially those produced from agro-industrial waste and byproducts. This perspective provides a brief introduction to the field as well as discussing some of the critical aspects to be considered as we accelerate the development of these novel alternative materials for a range of applications. [ABSTRACT FROM AUTHOR]

The current work focuses on the synthesis of the biodegradable film made from Sodium alginate (S.A), and then the addition of magnesium oxide nanoparticles (MgO-NPs) was synthesized by sol-gel technique. Glycerol which is a plasticizer is used to enhance the tensile strength (TS) and film expansion due to a decrease in intermolecular forces in the polymer chain. With the addition of olive oil (OE), the functional properties of control films were improved, which results in a lowering of water solubility, and moisture content but the tensile strength slightly decreased. The opacity, moisture absorption, and solubility of the film, thickness, tensile strength (TS), elongation (EB), ultraviolet-vis spectroscopy, scanning electron microscope (SEM), transmission electron microscopy (TEM) were used to characterize sodium alginate biofilm with the addition of MgO-NPs (SA1) and without the addition of MgO-NPs (SA2). But considering all other factors, the film (SA1) revealed a slower rate of degradation than the film (SA2). The film's TS and opacity are enhanced by MgO-NPs addition, while moisture content (WVP), solubility, and elongation at break are decreased. [ABSTRACT FROM AUTHOR]

Mismanaged plastic waste is a significant contributor to microplastic pollution in the environment, which can cause riverine pollution problems, adverse ecological effects, and pose risks to human health. In this context, extensive research has been conducted on microplastics (MPs) contamination in surface water in urban water environments. This work detected the abundance and characteristics of MPs in urban canals and sub-river (Mark-Hiao River) in the Vientiane capital. Additionally, the hazard risk to the ecological system posed by MPs was analyzed using calculated risk index values. The results showed that the abundance of MPs in the dry and rainy seasons ranged from 0.38 to 4.61 items/m3 and 1.23 to 7.10 items/m3, respectively. Among them, the most commonly found microplastic polymer types in the water samples were polypropylene (PP) > polyethylene (PE) > polystyrene > polyethylene terephthalate (PET) > nylon > other plastic. The diverse composition of MPs along the canals and Mark-Hiao River indicated medium and low hazard levels. However, it is necessary to take action to mitigate and manage the potential risks caused by microplastic pollution, ensuring the preservation of urban aquatic environment for future generations. Strategies recommended encompass promoting publicity and education, implementing green consumption practices, formulating and efficiently implementing regulations, improving the efficiency of wastewater treatment plant, encouraging the use of biodegradable plastics, refusing single-use and non-degradable plastics, and setting a monitoring standard. [ABSTRACT FROM AUTHOR]

The conversion of carbon-based solids, like non-recyclable plastics, biomass, and coal, into small molecules appears attractive from different points of view. However, the strong carbon–carbon bonds in these substances pose a severe obstacle, and thus—if such reactions are possible at all—high temperatures are required1–5. The Bergius process for coal conversion to hydrocarbons requires temperatures above 450 °C6, pyrolysis of different polymers to pyrolysis oil is also typically carried out at similar temperatures7,8. We have now discovered that efficient hydrogenation of different solid substrates with the carbon-based backbone to light hydrocarbons can be achieved at room temperature by ball milling. This mechanocatalytic method is surprisingly effective for a broad range of different carbon substrates, including even diamond. The reaction is found to proceed via a radical mechanism, as demonstrated by reactions in the presence of radical scavengers. This finding also adds to the currently limited knowledge in understanding mechanisms of reactions induced by ball milling. The results, guided by the insight into the mechanism, could induce more extended exploration to broaden the application scope and help to address the problem of plastic waste by a mechanocatalytic approach. Conventional methods to gasify or liquefy carbon-based polymers use high temperatures because of carbon–carbon bond stability. Here, the authors describe a mechanochemical ball milling method to break carbon–carbon bonds without heating. [ABSTRACT FROM AUTHOR]

Isolation and detection of microplastics (MP) in marine samples is extremely cost- and labor-intensive, limiting the speed and amount of data that can be collected. In the current work, we describe rapid measurement of net-collected MPs (net mesh size 300 µm) using a benchtop near-infrared hyperspectral imaging system during a research expedition to the subtropical North Atlantic gyre. Suspected plastic particles were identified microscopically and mounted on a black adhesive background. Particles were imaged with a Specim FX17 near-infrared linescan camera and a motorized stage. A particle mapping procedure was built on existing edge-finding algorithms and a polymer identification method developed using spectra from virgin polymer reference materials. This preliminary work focused on polyethylene, polypropylene, and polystyrene as they are less dense than seawater and therefore likely to be found floating in the open ocean. A total of 27 net tows sampled 2534 suspected MP particles that were imaged and analyzed at sea. Approximately 77.1% of particles were identified as polyethylene, followed by polypropylene (9.2%). A small fraction of polystyrene was detected only at one station. Approximately 13.6% of particles were either other plastic polymers or were natural materials visually misidentified as plastics. Particle size distributions for PE and PP particles with a length greater than 1 mm followed an approximate power law relationship with abundance. This method allowed at-sea, near real-time identification of MP polymer types and particle dimensions, and shows great promise for rapid field measurements of microplastics in net-collected samples. [ABSTRACT FROM AUTHOR]

Due to the flux of plastic debris entering the environment, it becomes urgent to document and monitor their degradation pathways at different scales. At the colloidal scale, the systematic hetero-association of nanoplastics with the natural organic matter complexifies the ability to detect plastic signatures in the particle collected in the various environments. The current techniques used for microplastics could not discriminate the polymers at the nanoscale from the natural macromolecules, as the plastic mass in the aggregate is within the same order. Only a few methods are available concerning nanoplastics identification in complex matrices, with the coupling of pyrolysis with gas chromatography and mass spectrometry (Py-GC–MS) as one of the most promising due to its mass-based detection. However, natural organic matter in environmental samples interferes with similar pyrolysis products. These interferences are even more critical for polystyrene polymers as this plastic presents no dominant pyrolysis markers, such as polypropylene, that could be identified at trace concentrations. Here, we investigate the ability to detect and quantify polystyrene nanoplastics in a rich phase of natural organic matter proposed based on the relative ratio of pyrolyzates. The use of specific degradation products (styrene dimer and styrene trimer) and the toluene/styrene ratio (RT/S) are explored for these two axes. While the size of the polystyrene nanoplastics biased the pyrolyzates of styrene dimer and trimer, the RT/S was correlated with the nanoplastics mass fraction in the presence of natural organic matter. An empirical model is proposed to evaluate the relative quantity of polystyrene nanoplastics in relevant environmental matrices. The model was applied to real contaminated soil by plastic debris and literature data to demonstrate its potential. [ABSTRACT FROM AUTHOR]

The increasing use of synthetic polymers and their disposal has raised concern due to their adverse effects on the environment. Thus, other sustainable alternatives to synthetic plastics have been sought, such as polyhydroxyalkanoates (PHAs), which are promising microbial polyesters, mainly due to their compostable nature, biocompatibility, thermostability, and resilience, making this biopolymer acceptable in several applications in the global market. The large-scale production of PHAs by microorganisms is still limited by the high cost of production compared to conventional plastics. This review reports some strategies mentioned in the literature aimed at production and recovery, paving the way for the bio-based economy. For this, some aspects of PHAs are addressed, such as synthesis, production systems, process control using by-products from industries, and advances and challenges in the downstream. The bioplastics properties made them a prime candidate for food, pharmaceutical, and chemical industrial applications. With this paper, it is possible to see that biodegradable polymers are promising materials, mainly for reducing the pollution produced by polymers derived from petroleum. [ABSTRACT FROM AUTHOR]

The combination of different polymers in the form of blended plastics has been used in the plastic industry for a long time. Nevertheless, analyses of microplastics (MPs) have been mainly limited to the study of particles made of single-type polymers. Accordingly, two members of the Polyolefins (POs) family, i.e., Polypropylene (PP) and Low-density Polyethylene (LDPE) are blended and extensively studied in this work due to their applications in industry as well as abundance in the environment. It is shown that 2-D Raman mapping only provides information about the surface of blended MPs (B-MPs). While complimentary 3-D volume analysis is needed to fully understand the presence of various polymers in such complex samples. Therefore, 3-D Raman mapping is applied to visualize the morphology of the distribution of polymers within the B-MPs together with the quantitative estimation of their concentrations. A parameter defined as the concentration estimate error (CEE) evaluates the precision of the quantitative analysis. Furthermore, the impact of four excitation wavelengths 405, 532, 633, and 785 nm is investigated on the obtained results. Finally, the application of a line-shaped laser beam profile (line-focus) is introduced for reducing the measurement time from 56 to 2 h. [ABSTRACT FROM AUTHOR]

Biodegradable plastics are among the most promising materials to replace conventional petroleum-based plastics that have caused many adverse impacts on the environment, such as pollution (land, water, etc.) and global warming. Among a range of biodegradable plastics, poly lactic acid (PLA) is not only widely available but also safe to be decomposed after its usage without polluting the environment. PLA is also in parity with other conventional plastics such as PP, PET in terms of various properties suitable for industrial usage such as mechanical, physical, biocompatibility and processability. Thus, PLA has become the most used biopolymers in many industries such as agriculture, automotive and packaging by having these characteristics. Its higher demand has contributed to a stable increment in the global PLA market. In fact, over the years, the market for PLA has grown up and will keep on expanding in the future. Overall, the PLA-based bioplastic would be an excellent substitute for the existing conventional plastics in various applications, hence will serve to protect the environment not only from pollution but also work as a sustainable and economical product. This paper will review all the recent related works and literature on PLA as the biodegradable material regarding its properties, usability, productivity and substitute. [ABSTRACT FROM AUTHOR]

Cellulose-based materials represent a renewable, biodegradable, and environmentally friendly alternative to plastic from fossil resources. Nanopaper is a strong and lightweight material formed from cellulose nanofibrils (CNFs). Paper and nanopaper have been considered as excellent alternatives to plastics for use in agriculture and for packaging applications. However, common for both paper and nanopaper is their hydrophilic character, and consequently, poor water-resistance properties. ORMOCER®s are a class of inorganic–organic polymers with excellent barrier and protective properties used for a range of coating applications. Here we present ORMOCER®-coated paper and nanopaper. The coated papers and nanopapers are characterized, both in terms of their morphology, hydrophobicity, and mechanical properties. We demonstrate that the pressure used during the pressing and drying of paper and nanopaper influence their tear and tensile—properties, and that the morphology of the coated nanopaper differs significantly from that of the coated paper. While the ORMOCER® was impregnated within the porous network of the paper, a well-defined two-layered morphology was obtained with the coated nanopaper. Further, the biodegradability of the nanopaper with and without coating was assessed. The degradation study demonstrated that both the pressure used during the pressing and drying of the nanopaper, and the composition of the ORMOCER®, influenced the rate of degradation. Taken together, ORMOCER®-coated paper and nanopaper are promising for the preparation of materials that are both water-resistant, renewable, and biodegradable. [ABSTRACT FROM AUTHOR]

Microplastics are ubiquitous in the environment, eventually becoming part of the geological record as 'technofossils'. However, research on the chronological characteristics of microplastics remains limited. This study reviewed dating methods, microplastic abundance, and microplastic polymer type in sedimentary cores globally. Furthermore, the 'evolution' of plastic types was compiled in sequence, and a microplastic chronological sequence in the sedimentary record was established. This microplastics chronological sequence was applied to 39 published cores with microplastic polymer analysis. The sediment age ranges determined by microplastic type were found to correspond to the published ages, indicating that microplastics could be useful for dating sedimentary cores on a centennial scale. Furthermore, good preservation and limited mobility of microplastics in burial records make microplastic dating an effective supplementary dating method for determining ages of Anthropocene sediments. [ABSTRACT FROM AUTHOR]

Exponential increase in the use and disposal of synthetic plastics has raised an alarming concern related to their adverse effect on the environment due to their recalcitrant nature and non biodegradability. Nevertheless, the depletion in the petrochemical sources made it imperative to search for other sustainable alternatives to synthetic plastics. This triggered the attention on biodegradable plastics produced from plants, animals and microbial sources that have excellent material properties like their synthetic counterparts. Polyhydroxyalkanoates (PHAs) are ineluctably promising microbial polyesters that have the competence to supersede traditional oil-based synthetic polymers which causes major disposal issues worldwide. The compostable nature, biocompatibility, thermostability, and resilience of these bio-based polymers make them an acceptable replacement in the global market. Their versatile material properties made them a propitious candidate in packaging, biomedicine, tissue engineering, biofuel production, nanocomposite formation, and other industrial applications. Despite their potential advantages, the commercialization of PHA is hindered majorly due to the high cost associated with their production and extraction. This review work majorly focuses on the production, extraction, applications and fermentation strategies for enhancing PHA production. The review also addresses the production of PHA from extremophiles, challenges associated with PHA production and sustainable substrates for PHA production using various agroindustrial wastes. [ABSTRACT FROM AUTHOR]

The research articles cover all steps of micro- and nanoplastic analysis, including sampling, sample preparation, polymer identification, quantification, and characterization. The analysis must include representative sampling and efficient sample preparation, as well as chemical identification, quantification, and characterization of the particles in the entire size range and in different media. As particle-based approaches, vibrational spectroscopy methods are strongly presented, including -Raman, -FTIR spectroscopy and NIR hyperspectral imaging enabling the reliable analysis of microplastics down to approx. 1 m (for detailed analysis), 10 m and 100 m to 300 m (for high-throughput monitoring), respectively. [Extracted from the article]

Plastic packaging has been widely used in utensils, equipment, packaging, among others. However, the widespread use of plastic materials, which originate from non-renewable sources, has generated a global pollution crisis due to its non-biodegradable profile, thus leading the scientific community and consumers to evaluate their choices. Therefore, studies on alternatives to prevent environmental damage have been carried out. The development of biodegradable packaging, produced with raw materials from renewable sources, such as polysaccharides, proteins, and others, has shown to be a viable alternative to minimize these problems. However, many challenges arise when using biodegradable compounds as a polymer matrix; thus, techniques that allow better knowledge of the materials can contribute significantly to improving the properties of interest in these packages, with an emphasis on thermal analysis. This review addressed the use of thermal analysis and experimental conditions to evaluate biodegradable films of different compositions, with an emphasis on thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), and differential scanning calorimetry (DSC). Small variations were observed for the experimental conditions, which can be associated with the different film constituents (polymer matrix, presence of nanocomposites and essential oils, etc.). [ABSTRACT FROM AUTHOR]

Plastic polymers are non-degradable solid wastes that have become a great threat to the whole world and degradation of these plastics would take a few decades. Compared with other degradation processes, the biodegradation process is the most effective and best way for plastic degradation due to its non-polluting mechanism, eco-friendly nature, and cost-effectiveness. Biodegradation of synthetic plastics is a very slow process that also involves environmental factors and the action of wild microbial species. In this plastic biodegradation, fungi play a pivotal role, it acts on plastics by secreting some degrading enzymes, i.e., cutinase', lipase, and proteases, lignocellulolytic enzymes, and also the presence of some pro-oxidant ions can cause effective degradation. The oxidation or hydrolysis by the enzyme creates functional groups that improve the hydrophilicity of polymers, and consequently degrade the high molecular weight polymer into low molecular weight. This leads to the degradation of plastics within a few days. Some well-known species which show effective degradation on plastics are Aspergillus nidulans, Aspergillus flavus, Aspergillus glaucus, Aspergillus oryzae, Aspergillus nomius, Penicillium griseofulvum, Bjerkandera adusta, Phanerochaete chrysosporium, Cladosporium cladosporioides, etc., and some other saprotrophic fungi, such as Pleurotus abalones, Pleurotus ostreatus, Agaricus bisporus and Pleurotus eryngii which also helps in degradation of plastics by growing on them. Some studies say that the degradation of plastics was more effective when photodegradation and thermo-oxidative mechanisms involved with the biodegradation simultaneously can make the degradation faster and easier. This present review gives current knowledge regarding different species of fungi that are involved in the degradation of plastics by their different enzymatic mechanisms to degrade different forms of plastic polymers. [ABSTRACT FROM AUTHOR]

Organic fraction of the municipal waste (OFMSW) is a valuable resource for biogas production through anaerobic digestion (AD). Bioplastics is widely used in daily activities, especially with food related items and collection bags, and can reach biogas plants through separate collection of OFMSW. PHAs, starch and cellulose based polymers with different compositions can degrade under anaerobic conditions. Cellulose and PHAs can degrade under both mesophilic and thermophilic conditions where, starch blends required thermophilic conditions in general. Other biopolymers, such as the most abundant PLA, are not able to degrade in the time frame of the facilities in most of the cases. Pre-treatment methods through abiotic and bio-augmentation, as well as post treatment methods, such as composting subsequent to AD are encountered as possible solutions for achieving better degradation or safer disposal of these polymers. The post-treatment/pre-disposal of the materials should be further studied as well as the pre-treatment methods. Studies on the effect of additives in biopolymers was not studied widely and requires further investigation. Degradation of biopolymers under AD, biogas production, pre-treatment and post-treatment methods as well as standard methods (or lack thereof) are discussed in detail in this paper, in order to point out to the possible scenarios that can be encountered when bioplastics end up in co-digestion conditions with organic material. [ABSTRACT FROM AUTHOR]

Plastics fragmentation into smaller debris, namely, micro- and nano-plastics (MPs and NPs), is a matter of global concern because of their wide distribution in terrestrial and marine environments. The latest research has focused mainly on aquatic ecosystems, and fragmentation of bioplastics into micro- and nano-particles (MBPs and NBPs) is not considered. The distribution, concentration, fate and major source of MPs, NPS, MBPs and NBPs in agroecosystems still need to be understood. The use of composts and sewage sludge from the organic fraction of municipal solid waste (OFMSW) treatment plants as soil amendments is likely to represent a major input of these debris. The present review provides insights into the current evidence of pollution from micro- and nano-particles of both fossil- and bio-origin in the OFMSW treatment, and aims at evaluating if the recycling of organic waste and its application as a soil fertilizer outweigh the risk of pollution in terrestrial environments. Huge unpredictability exists due to the limited numbers of data on their quantification in each source of possible solution. Indeed, the major hurdles arise from the difficult to quantify the micro-, especially the nano-, particles and subsequently assess the concentrations in the environments, as well as bioaccumulation risks, and toxic effects on organisms. [ABSTRACT FROM AUTHOR]

Biodegradable or transient electronics is an emerging technology whose key characteristic is an ability to dissolve, resorb, physically disappear or disintegrate in physiological environments after fulfilling their functions over prescribed time frames. Biodegradable electronics as temporary implants can be safely absorbed by the body, and as green electronics can effectively alleviate landfill and environmental issues caused by electronic wastes, which are expected to ultimately eliminate associated costs and risks resulting from recycling operations. In this review, the state of the art of the biodegradable polymers, their fabrication techniques, and potential applications in environment friendly electronic skins (e-skins) are comprehensively summarized and systematically discussed. In addition, the future outlook for the development of biodegradable e-skins is also discussed at the end. It is expected that this review will potentially provide vital tools and beneficial strategies for the design of biodegradable e-skins with the functions of diagnosis, therapy and green sensing that are beneficial for human healthcare and environmental protection. [ABSTRACT FROM AUTHOR]

Escalated production of plastic, their worldwide distribution and persistent nature finally results into their environmental accumulation causing severe threats to the ecological environment and biotic health. Thus, development of suitable measurements for environmental remediation of plastic may be an urgent issue in this plastic age. Some recent reviews have categorized the microbial species able to degrade different plastic polymers and the different factors effecting bio-degradation of plastic are poorly understood. This review comprehensively discusses bio-degradation of traditional and biodegradable plastic polymers both in natural and biological environment (gut microbes and fungi) to understand different factors regulating their degradation, and also shows how degradation of plastic polymers under abiotic factors influence subsequent biological degradation. Different physicochemical modifications like - breaking large polymers into small fragments by pre-treatment, functional groups enrichment, identifying potent microbial species (consortia) and engineering microbial enzymes might be crucial for bio-degradations of plastic. Effects of micro/nanoplastic and other chemical intermediates, formed during the bio-degradation of plastic, on species composition, abundance, growth, metabolism and enzymatic systems of microbes involved in the bio-degradation of plastic should be determined in future research. [ABSTRACT FROM AUTHOR]

Since biodegradable materials are unwittingly mixed with synthetic materials, this work aimed to study the feasibility of reliably identifying some biopolymers, treated as contaminants, in the recycling process of polyethylene terephthalate (PET). The results showed that the miscibility between PET-PLA and PET-PHB is good. However, PHB is degraded in the recycling of PET due to the high processing temperatures used; meanwhile, PET and TPS are poorly miscible, characteristics also reflected in the microstructure. The contaminants decrease the mechanical properties of the recycled PET. WCA, FTIR, and DSC, do not allow to identify of these contaminants. FESEM resulted in the most successful technique to detect the biodegradable polymers in the PET matrix. No significant degradation of PET under composting conditions was obtained due to the presence of biodegradable polymers, and the effects of the biodegradable contaminants continue to reduce the mechanical performance of the recycled PET after 1 year of storage. [ABSTRACT FROM AUTHOR]

Acrylic polymers (AP) are a diverse group of materials with broad applications, frequent use, and increasing demand. Some of the most used AP are polyacrylamide, polyacrylic acid, polymethyl methacrylates, and polyacrylonitrile. Although no information for the production of all AP types is published, data for the most used AP is around 9 MT/year, which gives an idea of the amount of waste that can be generated after products' lifecycles. After its lifecycle ends, the fate of an AP product will depend on its chemical structure, the environmental setting where it was used, and the regulations for plastic waste management existing in the different countries. Even though recycling is the best fate for plastic polymer wastes, few AP can be recycled, and most of them end up in landfills. Because of the pollution crisis the planet is immersed, setting regulations and developing technological strategies for plastic waste management are urgent. In this regard, biotechnological approaches, where microbial activity is involved, could be attractive eco-friendly strategies. This mini-review describes the broad AP diversity, their properties and uses, and the factors affecting their biodegradability, underlining the importance of standardizing biodegradation quantification techniques. We also describe the enzymes and metabolic pathways that microorganisms display to attack AP chemical structure and predict some biochemical reactions that could account for quaternary carbon-containing AP biodegradation. Finally, we analyze strategies to increase AP biodegradability and stress the need for more studies on AP biodegradation and developing stricter legislation for AP use and waste control. Key points: • Acrylic polymers (AP) are a diverse and extensively used group of compounds. • The environmental fates and health effects of AP waste are not completely known. • Microorganisms and enzymes involved in AP degradation have been identified. • More biodegradation studies are needed to develop AP biotechnological treatments. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHA) are bio-based polymers with the potential of replace petrochemical plastics. Nevertheless, PHA commercialization is still low, due to the high production cost associated with industrial-scale development. The most cost/efficient PHA recovery strategies use organochlorine compounds or harsh reagents implying a high environmental impact. Therefore, the importance of developing an economical and efficient recovery strategy cannot be overestimated. Thus, new approaches have been reported that look for creating a sustainable production process, such as biological recovery, PHA secretion or predator bacteria. Moreover, if bioplastics would become the plastics of the future, it must be necessary to replace the traditional PHA extraction methods by environmentally friendly options. Hence, the aim of this review is to analyze trends in the development of efficient technologies for the sustainable recovery of polyhydroxyalkanoates (PHA) produced by microorganisms. [ABSTRACT FROM AUTHOR]

To solve the environmental disaster that is generated by legacy plastics accumulation, researchers are looking to design plastics with enhanced end-of-life options, but many circular plastics do not meet industrial requirements. Here, we highlight a metal-free approach to produce chemically recyclable poly(1,3-dioxolane) with ultra-high molecular weight and comparable properties to one of the most produced plastics, polyethylene. [ABSTRACT FROM AUTHOR]

The mechanisms of microbial action on synthetic plastics are analyzed, with the focus on the most widespread polymers produced on an industrial scale. The effect of microbial enzymes on plastic biodegradation and the role of multispecies biofilms in biocorrosion are considered. The main approaches for protection of synthetic plastics from microbially caused damage are discussed. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this review is to evaluate previous life cycle assessment (LCA) studies of first- and second-generation bioplastics, to understand the state of the art and the main problems addressed during the development of new bioplastics. Furthermore, it provides an overview on land use change (LUC) impacts accounted for, methodologies chosen, and the results obtained. Methods: Studies related to the impact assessment of bioplastics and published between 2007 and 2018 were gathered. Five keyword strings were used to perform a wide search and select relevant LCA studies. The study aimed to analyze critical methodological aspects in LCA, in order to determine the most common choices made during biobased material analyses, as well as major limitations. Three filters were applied to select comparable studies, ending with a final number of 17 papers. Recommendations were obtained by comparing common practices performed by different authors with suggested best available practices mentioned in handbooks and guidelines. Interestingly, LUC metrics and impacts were, most of the time, neglected. Thus, a specific assessment and discussion was performed regarding the methods used to quantify LUC impacts, considering its importance during the production of biobased materials. Results and discussion: The study discussed the main environmental problems linked to the development of new biomaterials. LCA of agricultural products or systems, when compared with fossil-based counterparts, is expected to show higher environmental impacts in categories directly affected by fertilizer use, occupied and transformed land, among others. Thus, studies that included additional impact categories besides global warming (e.g., eutrophication or acidification) concluded that biobased materials present higher impacts, recommending improvements in farming practices to improve their overall environmental profile. Moreover, this review gathered methodologies used to account for LUC impacts and the results obtained. The main constraint of including LUC impacts was the lack of a standardized methodology, as well as large uncertainties in existing methodologies. Conclusions: Most studies concluded that improvements in farming practices might reduce the attributed environmental impacts with the reduction of the amount of land, fertilizer, pesticides, and water used. Studies computing LUC impacts agreed on the importance of including these impacts and concluded that greenhouse gas emissions of bioplastic production would increase, but in most cases would still be lower than the impact of their fossil-based counterparts. However, challenges remain when computing LUC impacts that need to be tackled when working with the available methodologies, including the collection of reliable inventory data (site-specific or regional data) and regionalized characterization factors. [ABSTRACT FROM AUTHOR]

Biodegradable polymers were introduced in the past decades in order to address the issue of plastic pollutions, and these materials have thus required the development of methodologies to understand and evaluate their disintegration. The aim of this study was to simulate the organic fraction of municipal solid waste (OFMSW) treatment in laboratory-scale and to assess the biodegradation of poly(lactic acid) (PLA) water bottles and starch-based bags under real industrial conditions of anaerobic digestion and aerobic composting. Methane production and loss of mass were determined to estimate the anaerobic degradation; whereas phytotoxicity tests were carried out to provide an evaluation of the compost quality. To visualize the effects on the materials, SEM analyses, differential scanning calorimetry (DSC) and FT-IR/ATR spectroscopy were performed. Different outcomes were found for the tested bioplastics products. PLA bottles didn't biodegrade under anaerobic conditions and the pieces appeared wrap up at the end, while starch-based bioplastic bags performed 85.79% of disintegration degree. CH4 production was between 40 and 50% for both the products. Phytotoxicity test on the final composts highlighted negative effects on both selected seeds for PLA solutions. Water-soluble lactic acid from degraded PLA bottle significantly reduced the pH of compost affecting seed germination and germination indexes. Both bioplastics showed chemical modification according to DSC and FT-IR/ATR analyses. [ABSTRACT FROM AUTHOR]

Microbial polyhydroxyalkanoates (PHAs) are biopolyesters produced by microorganisms as intracellular granules under nutrient stress. Due to non-toxic and biodegradable behavior these polyesters are a sustainable source of wide range of biomaterials such as bioplastics. As a result of excellent polymeric properties such as melting temperatures (Tm), glass transition temperature (Tg), crystallinity, Young's modulus and stress to break ratio these polyesters are capable of replacing the synthetic plastics. Bioplastics produced using PHAs as biomass source can be used for packaging material and disposable products on the other hand biofuels can also be generated using PHAs. PHAs find countless applications in industry, agriculture, pharmaceuticals and health. A large number of bacterial, microalgal and fungal species can produce these polyesters. Bacterial species such as Bacillus megaterium, Pseudomonas aeruginosa, P. oleovorans, P. stutzeri and Cupriavidus necator are some highly studied microorganisms for PHA production. This review summarizes the most important aspects of PHAs, crystalline and granular structure of PHA biosynthesizing genes and their relevant proteins. Thermal and physical properties, sources, extraction, purification methods of PHAs are briefly discussed. Applications of PHAs, phylogenetic analysis of Pseudomonas sp. in term of its PHAs synthesizing genes, future prospects and possible outcomes are discussed. [ABSTRACT FROM AUTHOR]

Current research in industrial microbiology and biotechnology focuses on the production of biodegradable microbial polymers as an environmentally friendly alternative to still dominant fossil-based plastics. Microbial polymers have an extensive biotechnological potential and are already widely used in a variety of fields ranging from medicine to technology. However, their increase in production and wider use is hampered by the high cost of raw materials and therefore requires a focus on cheaper inputs, including dairy by-products and waste such as cheese whey (CW). This is an environmentally unfriendly by-product of milk processing and reducing it would also reduce the risk of environmental pollution. This review summarises current knowledge on the use of CW and derived products to obtain commercially important microbial polymers, including information about producer cultures, fermentation techniques and methods used, composition of culture medium, cultivation conditions and productivity of bioprocesses. The main methods and applications of cheese whey pre-treatment are also summarised. [ABSTRACT FROM AUTHOR]

Biofouling is one of the major worldwide problems associated with the vessel due to its accumulation with the surface of the ship hull. The biofouling is the main origin of the coating's deterioration that ultimately leads to bio-corrosion, roughness and drag, resulting in an enormous increase in the fuel consumption. Although Tributyltin (TBT) has been used as a pioneer class of antifoulant to overcome this problem, however, after the legal restriction on TBT, some biocides have been used as its alternatives. These biocides are potentially harmful to the environment due to the higher release rate in the aquatic environment. This review paper focuses on the progress made in eco-friendly antifouling coating techniques, using control biocide release principal for marine application. The three main strategies, hydrophilic, hydrophobic, and biodegradable antifouling coating, are reviewed. Biodegradable antifouling coating is a new promising route based on the combination of eco-friendly biocide with dynamic surfaces by utilizing degradable polyurethane, polyester acrylate, and modified polyester based polymers. They are used as a carrier of antifoulant, which control the release rate and also show excellent antifouling activity in the marine coatings due to tunability, sustainability, and mechanical performance, therefore, they have a longer shelf period. Moreover, this review focuses on the challenges associated with vessel surface coating and their possible solutions. [ABSTRACT FROM AUTHOR]

During the past century, plastics have become a natural element in our every-day life. Lately however, an awareness about the fossil origin and often non-degradable nature of many plastics is rising. This has resulted in the emergence of some bio-based and/or biodegradable plastics, often produced from renewable resources. One possible candidate for bioplastics production could be found in cellulose. This paper aims at contributing information regarding a cellulose derivative, which could possibly be used in foamed plastics applications. Therefore, the reduction of the chain-length of a methyl ethyl hydroxyethyl cellulose (MEHEC), assessed by size exclusion chromatography, and the effect of chain-length on the foaming behaviour were studied. The foaming was accomplished with a hot-mould technique using aqueous polymer solutions. The generated steam was here used as the blowing agent and important parameters were polymer concentration and solution viscosity. The density of the produced foams was assessed and was in some cases comparable to that of commodity foams. It was found that reducing the chain-length enabled an increase of the initial polymer concentration for the foaming process. This is believed to be beneficial for creating more structurally stable foams of this type. [ABSTRACT FROM AUTHOR]

A process was developed for producing biocompatible and biodegradable polymer films based on high-molecular-weight polylactide with properties necessary for medical and agricultural applications. A method was devised for the inclusion of active substances (gentamicin sulfate, lincomycin hydrochloride, or cefotaxime) into high-molecular-weight polylactide films. The rate of release of active substances from polylactide can vary with time according to a decaying exponential law or nearly linearly. The release of active substances is significantly affected by pH of the solution surrounding the film. It was found that the dynamics of release of active substances from biocompatible biodegradable polymer films based on high-molecular-weight polylactide depends on the properties of the immobilized substance, the film preparation method, and the conditions of extraction. The biocompatible biodegradable polymer films based on high-molecular-weight polylactide are quite suitable for the manufacture of coatings for stents and prostheses with prolonged and controlled drug release into the surrounding tissues and for agricultural applications to improve crop preservation. [ABSTRACT FROM AUTHOR]

Bioplastic materials from renewable polymers, like proteins, constitute a highly interesting field for important industrial applications such as packaging, agriculture, etc., in which thermo-mechanical techniques are increasingly being used. This study assesses bioplastic materials produced by injection from blends previously prepared in a batch mixer using various protein concentrates and isolates. A mixing time of 5 min has been selected in order to ensure correct homogenous blends. A comparison between different protein-based specimens was performed by dynamic mechanical thermal analysis, tensile strength, water uptake and transmittance tests. The comparison reveals that the protein nature and the percentage of plasticizer lead to bioplastics with different properties and, consequently, different applications. Protein concentrates and isolates, wastes and surpluses from the food industry, may be useful for producing bioplastics with suitable mechanical properties and processability, as well as biodegradability, by means of suitable mixing and injection moulding conditions. [ABSTRACT FROM AUTHOR]

Polylactide (PLA) is a major biodegradable polymer, which has received extensive interests over the past decades and holds great potential to replace several petroleum-based polymeric materials. Nevertheless, the inherent brittleness and low impact strength have restricted its invasion to niche markets. In this paper, the authors demonstrate that the entirely bio-sourced blends, namely PLA and castor oil-based polyurethane prepolymer (COPUP), were first melt-compounded in an effort to prepare novel biodegradable materials with an excellent balance of properties. NCO-terminated COPUP was successfully synthesized and subsequently mixed with variable concentration of PLA matrix using melt-compounded by twin-screw extrusion technique. The miscibility, phase morphology, mechanical properties, and thermal resistance of the blends were investigated. During FTIR analysis, it suggests that the interfacial compatibilization between COPUP and PLA phase occurred by the reaction of -NCO group of MDI with terminal hydroxyl group of PLA. DMA analysis showed that COPUP and PLA showed some limited miscibility with shifted glass transition temperature. The morphologies of fracture surface showed a brittle-to-ductile transition owing by the addition of COPUP. The crystallization behavior was studied by differential scanning calorimeter (DSC). The strain at break and notched impact strength of PLA/COPUP blends were increased more than 112-15.4 times elegant of neat PLA; the increase is superior to previous toughening effect by using petroleum-based tougheners. Furthermore, the thermal resistances and melt flow properties of the materials were also examined by analysis of the melt flow index and heat deflection temperature use in the work. With enhanced toughness, the PLA/COPUP blends could be used as replacements for some traditional petroleum-based polymeric materials. [ABSTRACT FROM AUTHOR]

Nylon 4 is a biodegradable polymer which can be produced from the monomer of pyrrolidone. Gammaaminobutyric acid (GABA) is a precursor of pyrrolidone used for the production of bioplastics. In this study, Escherichia coli were engineered to produce gammaaminobutyric acid from glucose via an alternative novel pathway by the introduction of synthetic scaffolds. The GABA pathway constructed contained succinate dehydrogenase, succinate-semialdehyde dehydrogenase and GABA aminotransferase to redirect the Krebs cycle flux to GABA production. By introduction of a synthetic scaffold, production of 0.64 g/L GABA was achieved at 30°C and pH 6.5. Final GABA concentration was increased by 11.3% via the inactivation of competing pathways, and higher initial glucose concentration led to the enhanced final GABA concentration of 1.01 g/L. [ABSTRACT FROM AUTHOR]

Cutinase-like esterase from the yeasts Pseudozyma antarctica (PaE) shows strong degradation activity in an agricultural biodegradable plastic (BP) model of mulch films composed of poly(butylene succinate- co-adipate) (PBSA). P. antarctica is known to abundantly produce a glycolipid biosurfactant, mannosylerythritol lipid (MEL). Here, the effects of MEL on PaE-catalyzed degradation of BPs were investigated. Based on PBSA dispersion solution, the degradation of PBSA particles by PaE was inhibited in the presence of MEL. MEL behavior on BP substrates was monitored by surface plasmon resonance (SPR) using a sensor chip coated with polymer films. The positive SPR signal shift indicated that MEL readily adsorbed and spread onto the surface of a BP film. The amount of BP degradation by PaE was monitored based on the negative SPR signal shift and was decreased 1.7-fold by MEL pretreatment. Furthermore, the shape of PBSA mulch films in PaE-containing solution was maintained with MEL pretreatment, whereas untreated films were almost completely degraded and dissolved. These results suggest that MEL covering the surface of BP film inhibits adsorption of PaE and PaE-catalyzed degradation of BPs. We applied the above results to control the microbial degradation of BP mulch films. MEL pretreatment significantly inhibited BP mulch film degradation by both PaE solution and BP-degradable microorganism. Moreover, the degradation of these films was recovered after removal of the coated MEL by ethanol treatment. These results demonstrate that the biodegradation of BP films can be readily and reversibly controlled by a physical approach using MEL. [ABSTRACT FROM AUTHOR]

The development of biodegradable plastic mulch films for use in agriculture has been ongoing for decades. These films consist of mixtures of polymers with various additives. As a result, their physical and chemical properties differ from those of the pure polymers often used for in vitro enzymatic and microbial degradation studies, raising questions about the biodegradation capability of mulch films. Currently, standards exist for the biodegradation of plastics in composting conditions but not in soil. Biodegradation in soil or compost depends on a complex synergy of biological and abiotic degradative processes. This review discusses the physicochemical and structural properties of biodegradable plastic mulches, examines their potential for on-site decomposition in light of site-to-site variance due to environmental and biological conditions, and considers the potential for long-term effects on agroecosystem sustainability and functionality. [ABSTRACT FROM AUTHOR]

The development of bio-based films from proteins for their utilization as packaging materials and composites has gained popularity due to the availability, renewable nature, and biodegradability of proteins. The most studied of these polymers is sourced from soy. However, other sources of proteins show great commercial potential when transformed into films. As such, zein from corn and keratin from low-value chicken feather can be plasticized into films which exhibit good mechanical properties. Films derived from pea proteins can resist UV light transmission due to the presence of disulfide bonds within the network and the presence of amino acids such as tyrosine, tryptophan, and phenylalanine. Proteins from rapeseed have not been extensively studied as feedstocks for bio-based films but show great potential since their amino acid composition is similar to soy proteins. This review aims at combining and condensing the body of research performed on the synthesis of zein-, keratin-, pea-, canola-, and rapeseed-based films. The structural diversity of these proteins highly influences their processing methods and the physical properties of the resulting films. The potential applications of these bio-based materials are also highlighted. [ABSTRACT FROM AUTHOR]

Oxidatively degradable polyethylene is finding widespread use, particularly in applications such as single use packaging and agriculture. However, the key question which still remains unanswered is the ultimate fate and biodegradability of these polymers. During a short-time frame only the oxidized low molecular weight fraction will be amenable to significant biodegradation. The short-time frame biodegradation potential of different LDPE-transition metal formulations was, thus, explored through a simple chemical extraction of oxidized fraction. In addition the effectiveness of different transitions metals was evaluated by comparing the extractable fractions. Blown LDPE films modified with different transition metal based pro-oxidants were thermo-oxidized at 60 °C over extended periods. The structural changes occurring in the polymer were monitored and the oxidized degradation products formed as a result of the aging process were estimated by extractions with water and acetone. The extractable fraction first increased to approximately 22 % as a result of thermo-oxidative aging and then leveled off. The extractable fraction was approximately two times higher after acetone extraction compared to extraction with water and as expected, it was higher for the samples containing pro-oxidants. Based on our results in combination with existing literature we propose that acetone extractable fraction gives an estimation of the maximum short-term biodegradation potential of the material, while water extractable fraction indicates the part that is easily accessible to microorganisms and rapidly assimilated. The final level of biodegradation under real environmental conditions will of course be highly dependent on the specific environment, material history and degradation time. [ABSTRACT FROM AUTHOR]