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Plastic waste has recently become a major global environmental concern and one of the biggest challenges has been seeking for alternative management options. Several studies have revealed the potential of several coleopteran species to degrade plastics, and this is the first research paper on plastic-degradation potential by lesser mealworms from Africa. This study evaluated the whole mitogenomic profile of the lesser mealworm to further identify the insect. The ability of the mealworm to consume Polystyrene (PS) was also evaluated alongside its associated gut microbiota diversity. Our results showed a complete circular mitochondrial genome which clustered closely to the Alphitobius genus but also suggested that our insect might be a new subspecies which require further identification. During the PS feeding trials, overall survival rates of the larvae decreased when fed a sole PS diet while PS intake was observed to increase over a 30-day period. The predominant bacteria observed in larvae fed PS diets were Kluyvera, Lactococcus, Klebsiella, Enterobacter, and Enterococcus, while Stenotrophomonas dominated the control diet. These findings demonstrated that the newly identified lesser mealworm can survive on a PS diet and has a consortium of important bacteria strongly associated with PS degradation. This work provides a better understanding of bioremediation applications, paving the way for further research into the metabolic pathways of plastic-degrading microbes and bringing hope to solving plastic waste pollution while providing high-value insect protein towards a circular economy. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are one of the major substantial pollutants in the environment and are stored in sediments worldwide, especially in marine environments. This study shed light on the abundance, distribution, sources and chemical composition of MPs present in the surface sediments collected from the shelf part of the southeast coast of India, Bay of Bengal. A total of twenty-seven surface sediment samples were collected to study MPs pollution. The abundance and morphological characteristics of MPs were determined by counting using an Olympus SXZ7 stereo microscope. Raman spectroscopy analysis was used to identify the polymer type of the MPs. The average abundance of MPs in the study area is 460±275 MPs/kg in dry sediment. Regarding colour, transparent particles were predominant (46.42%), followed by blue, green, brown, etc. With respect to particle shape and size, fibres and 500-µm sized MPs are abundant. Polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), high-density polyethylene (HDPE), low-density polyethylene (LDPE) and polystyrene (PS) are the polymer types characterised in the study area. The higher abundance of MPs in the study area can be attenuated to human interruptions, viz., tourism, fishing and inappropriate sewage disposal in the marine environment. In addition to this, population density also plays an important role in providing MPs to the marine environment. This study provides the most valuable data to extrapolate the research for mitigating MP pollution in oceans. It also informs mankind about their disastrous activities on the marine environment, which is expected to recuperate quickly and negatively impact human health and the functionality of the marine system. [ABSTRACT FROM AUTHOR]

Jackfruit seeds have been explored as one interesting alternative starch source to be used in the production of sustainable bioplastics. In this context, this work aimed to investigate the effect of sorbitol concentration, one alternative plasticizer to glycerol, and the starch properties of the films. A complete factorial experimental study was done based on five different concentrations of starch (2, 3, 4, 5, and 6% w/w) and sorbitol (40, 50, 60, 70, 80 g per 100 g of starch). The films were produced by casting technique and were characterized about thickness, optical properties, moisture resistance, mechanical properties, and morphology. The optical properties revealed opaque films, with opacity values ranging from 16.04 to 21.26%. Regarding moisture resistance, the less hydrophilic films showed lower plasticizer content. The water solubility varied from 25.48 to 38.93%; the water vapor permeability ranged from 9.99 to 11.82 × 10−9 (g/m s Pa) and the free energy of hydrophobic interactions varied from − 28.16 to 40.13 mJ m−1. Concerning the mechanical properties, the tensile strength of the films ranged from 3.55 to 9.25 MPa, and increasing the sorbitol concentration decreased the tensile strength and increased the elongation at break. The morphology and structure analysis showed that starch granules were not fully gelatinized, with microbubbles and grooves in the film matrix. This study showed the great potential of jackfruit seed starch and sorbitol in the manufacture of biodegradable films as alternative sustainable packaging. [ABSTRACT FROM AUTHOR]

This study examined plastics and toxic metals in municipal solid waste compost from various regions in Sri Lanka. Plastics were extracted using density separation, digested using wet peroxidation, and identified using Fourier Transform Infra-Red Spectroscopy in Attenuated Total Reflection mode. Compost and plastics were acid-digested to quantify total Cd, Cu, Co, Cr, Pb, and Zn concentrations and analyzed for the bioavailable fraction using 0.01 M CaCl2. Notably, plastics were highly abundant in most compost samples. The main plastic types detected were polyethylene, polypropylene, and cellophane. However, the average Cd, Cu, Co, Cr, Pb, and Zn levels were 0.727, 60.78, 3.670, 25.44, 18.95, and 130.7 mg/kg, respectively, which are well below the recommended levels. Zn was the most bioavailable (2.476 mg/kg), and Cd was the least bioavailable (0.053 mg/kg) metal associated with compost. The Contamination factor data show that there is considerable enhancement of Cd and Cu, however, Cr, Cu, Co, and Pb are at low contamination levels. Mean geo accumulation index values were 1.39, 1.07, − 1.06, − 0.84, − 0.32, and 0.08 for Cd, Cu, Co, Cr, Pb, and Zn. Therefore, the contamination level of compost samples with Cd and Cu ranges from uncontaminated to contaminated levels, whereas Co, Cr, Pb, and Zn are at uncontaminated levels. Despite no direct metal-plastic correlation, plastics in compost could harm plants, animals, and humans due to ingestion. Hence, reducing plastic and metal contamination in compost is crucial. [ABSTRACT FROM AUTHOR]

Using biodegradable material derived from renewable resources as petroleum-based plastics replacement is a promising way towards sustainable development. However, the insufficient mechanical properties and complex manufacturing process of bioplastics still need to be improved for high-quality food packages. Herein, we report a top-down strategy to transform natural wood into a clear wood packaging film through scalable delignification and polyvinyl alcohol (PVA) infiltration. The wood packaging film demonstrates a laminated structure with completely collapsed cell walls and PVA intertwined together after energy-saving air drying, resulting in high light transmittance with low haze, good mechanical performance, and high barrier performance for oxygen and water vapor. Molecular dynamics simulations reveal the underlying fracture mechanism between cellulose and PVA, which effectively enhances the Young's modulus and strength of the wood packaging film. These findings contribute to the development of biodegradable and strong packaging materials, as well as other food-related applications, using sustainable wood. [ABSTRACT FROM AUTHOR]

Increasing human population demands more usage of consumable items thus causes more destruction to the environment by developing advanced materials and technologies. Synthetic plastic is one of the most used material in daily life which results in accumulation of non-degradable waste material that stays in the environment for thousands of years and creates plastic pollution. Many species on the earth suffer from pollution caused by plastic and it is one of the leading causes of global warming. For sustainable development, we need to protect our environment from plastic pollution by making use of biodegradable materials. In the past few years, biodegradable materials with plastic like properties have gained much attention. They have been made from biomass such as sugarcane, corn, wheat, rice, banana peels, etc. Such desirable properties are also present in PHAs (polyhydroxyalkanoates) synthesized by microorganisms. Several types of PHAs have been discovered from bacteria and used as a bioplastic candidate. However, there are major challenges also such as high production cost and expensive raw material which limits its commercial applications. Modern tools and strategies have allowed precise metabolic engineering of various microorganisms to produce PHAs using highly efficient microbial cell factories. This review article focuses on the research done on the microbial bioplastic production and its various applications. We have also discussed the future perspectives of bioplastic for sustainable development. [ABSTRACT FROM AUTHOR]

Plastic pollution is a problem that threatens the future of humanity, and various methods are being researched to solve it. Plastic biodegradation using microorganisms is one of these methods, and a recent study reported that plastic-degrading microorganisms activated by plasma increase the plastic decomposition rate. In contrast to microbial sterilization using low-temperature plasma, microbial activation requires a stable plasma discharge with a low electrode temperature suitable for biological samples and precise control over a narrow operating range. In this study, various plasma characteristics were evaluated using SDBD (Surface Dielectric Barrier Discharge) to establish the optimal conditions of plasma that can activate plastic-degrading microorganisms. The SDBD electrode was manufactured using low-temperature co-fired ceramic (LTCC) technology to ensure chemical resistance, minimize impurities, improve heat conduction, and consider freedom in designing the electrode metal part. Plasma stability, which is important for microbial activation, was investigated by changing the frequency and pulse width of the voltage applied to the electrode, and the degree of activation of plastic-degrading microorganisms was evaluated under each condition. The results of this study are expected to be used as basic data for research on the activation of useful microorganisms using low-temperature plasma. [ABSTRACT FROM AUTHOR]

The present study examines the use of waste cooking oil (WCO) as a substrate for medium-chain-length polyhydroxyalkanoates (mcl-PHA) production by Pseudomonas rhizophila S211. The genome analysis revealed that the S211 strain has a mcl-PHA cluster (phaC1ZC2DFI) encoding two class II PHA synthases (PhaC1 and PhaC2) separated by a PHA depolymerase (PhaZ), a transcriptional activator (PhaD) and two phasin-like proteins (PhaFI). Genomic annotation also identified a gene encoding family I.3 lipase that was able to hydrolyze plant oils and generate fatty acids as favorable carbon sources for cell growth and PHA synthesis via β-oxidation pathway. Using a three-variable Doehlert experimental design, the optimum conditions for mcl-PHA accumulation were achieved in 10% of WCO-based medium with an inoculum size of 10% and an incubation period of 48 h at 30 °C. The experimental yield of PHA from WCO was 1.8 g/L close to the predicted yield of 1.68 ± 0.14 g/L. Moreover, 1H nuclear magnetic resonance spectroscopy analysis confirmed the extracted mcl-PHA. Overall, this study describes P. rhizophila as a cell factory for biosynthesis of biodegradable plastics and proposes green and efficient approach to cooking oil waste management by decreasing the cost of mcl-PHA production, which can help reduce the dependence on petroleum-based plastics. [ABSTRACT FROM AUTHOR]

Microplastics have become a pressing environmental issue due to their widespread presence in our ecosystems. Among various plastic components, polyethylene (PE) is a prevalent and persistent contaminant. Hydrothermal gasification (HTG), a promising technology for converting PE into syngas, holds great promise for mitigating the microplastic problem. In this study, we employ ReaxFF molecular dynamics simulations to investigate the HTG process of PE, shedding light on the intricate relationships between temperature, water content, carbon conversion efficiency, and product distributions. The results reveal that hydrothermal gasification of PE is a complex process involving multiple reaction pathways. Consistently with experimental findings, the calculations indicate that the gas phase exhibits a substantial hydrogen fraction, reaching up to 70%. Interestingly, our simulations reveal a dual role of water content in the HTG process. On one hand, water enhances hydrogen production by promoting the gas formation. On the other hand, it elevates the activation energy required for PE decomposition. Depending on the water content, the calculated activation energies range from 176 to 268 kJ/mol, which are significantly lower than those reported for thermal gasification (TG). This suggests that HTG may be a more efficient route for PE conversion. Furthermore, this study highlights the importance of optimizing both temperature and water content in HTG systems to achieve high yields of hydrogen-rich syngas. The results obtained from our ReaxFF MD simulations demonstrate the robustness of this computational methodology in elucidating complex chemical reactions under extreme conditions. Our findings offer critical insights into the design of advanced waste management strategies for microplastics and contribute to the development of sustainable practices for resource recovery. This work underscores the potential of HTG as a key technology for addressing the global challenge of plastic pollution. [ABSTRACT FROM AUTHOR]

Microplastics have been recently detected in many environmental media and living organisms, yet their transfer and toxicity to humans are poorly known. Here, we review microplastic transfer in the food chain with focus on microplastic pollution sources, methods to analyze microplastics in food, health impact of food-related microplastic exposure, and remediation of microplastic pollution. Microplastic pollution sources include seafood, food additives, packaging materials, and agricultural and industrial products. Remediation techniques comprise the use of microbial enzymes and biofilms. Microplastic detection methods in food rely on separation and quantification by optical detection, scanning electron micrography, and Fourier-transform infrared spectroscopy. Human health impact following microplastic ingestion include cancers, organ and respiration damage, and reproductive impairments. Overall, microplastic toxicity is mainly due to their ability to enter the metabolism, adsorption into the circulatory system for translocation, and difficulty, if not impossibility, of excretion. [ABSTRACT FROM AUTHOR]

Bioplastics appear as an alternative to fossil fuel-derived plastics because bioplastics are carbon neutral and often biodegradable, thus potentially solving the issues of plastic pollution and climate change. In particular, polylactic acid is a substitute for traditional petrochemical-based polymers. Here, we review polylactic acid production with focus on surface modification and integration of bioactive compounds. Surface can be modified by chemical treatment, photografting, surface entrapment, plasma treatment, and coating. Bioactive compounds can be incorporated by encapsulation, impregnation, melt blending, solvent casting, electrospinning, and in situ polymerization. Biomedical and packaging applications are discussed. [ABSTRACT FROM AUTHOR]

The fabrication of ultra-tough biodegradable nanocomposite films with antibacterial activity and antioxidant properties remains a huge challenge. Herein, we developed a super-tough antibacterial biodegradable poly(vinyl alcohol) (PVA) nanocomposite film by simply introducing highly effective antibacterial agent PDA@LS-Ag into PVA matrix. The antibacterial agent PDA@LS-Ag was synthesized from the mussel-inspired polydopamine (PDA) and green biomass sodium lignosulfonate (LS) via a facile microwave-assisted reduction strategy, in which PDA played the role of reducing agent and LS performed as the dispersant. The tensile strength of the PVA nanocomposite film with 5 wt% addition of PDA@LS-Ag reached up to 131.7 MPa, which was far higher than most of engineering plastics. The excellent mechanical performance was resulted from the synergistic effect of the unique nanoscale phase-separation structure and the dense hydrogen bonds between the PDA@LS-Ag nanoparticles and PVA matrix. Owing to the existence of silver nanoparticles and rich phenolic hydroxyl groups, the PDA@LS-Ag nanoparticles also endued the composite film with good antibacterial activity, outstanding antioxidant activity, and UV-shielding properties. As the biomass LS, PDA, and the PVA matrix are all biodegradable, this work provides a feasible way for preparing highly strong and super-tough biodegradable nanocomposite films with antibacterial and antioxidant properties. [ABSTRACT FROM AUTHOR]

The utilization of biodegradable hydrogels based on natural polysaccharides in the agricultural and biomedical sectors is anticipated to be a growing field of interest. Due to increasing environmental pollution, the current global goal is to synthesize sustainable materials based on natural polysaccharides to conserve natural resources for the future. In this study, we synthesized an amla-based hydrogel, denoted as AL-g-poly(MAA), using the graft-free radical polymerization method. Methacrylic acid (MAA) was employed as the monomer, N,N′-methylenebisacrylamide (MBA) served as the crosslinker, and ammonium persulfate (APS) acted as the initiator. The synthesized hydrogel, AL-g-poly(MAA), underwent optimization by adjusting seven parameters: initiator, solvent, time, monomer, power, pH, and crosslinker, to achieve the highest swelling percentage. The optimized values were as follows: solvent: 10 ml, time: 150 s, monomer: 0.039 mol/L, power: 60%, pH: 7, and crosslinker: 0.0648 mol/L. The cross-linking process was confirmed through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA) techniques. The swelling behavior of the synthesized hydrogels was determined in saline solutions with varying ionic strengths and concentrations, revealing maximum swelling in solutions with lower ionic strengths and concentrations. Additionally, the density and porosity of the hydrogels were examined. The biodegradability of AL-g-poly(MAA) was tested through soil burial and vermicomposting experiments, demonstrating its significant potential for agriculture applications. Furthermore, both the backbone and the synthesized hydrogel were evaluated for antibacterial activity against four bacterial strains (Burkholderia gladioli, Klebsiella pneumoniae, Staphylococcus aureus, and Bacillus cereus), revealing strong potential as an antimicrobial agent and therefore having applications in the biomedical field. The mechanism underlying the inhibitory effect of synthesized AL-g-poly(MAA) hydrogel on bacterial cell membranes is also discussed. [ABSTRACT FROM AUTHOR]

Context: Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable plastic. It was introduced to the plastics market in 1998 and since then has been widely used around the world. The main idea of this research is to perform quantum chemical calculations to study the potential toxicity of PBAT and its degradation products. We analyzed the electron transfer capacity to determine its potential toxicity. We found that biodegradable products formed with benzene rings are as good electron acceptors as PBAT and OOH•. Our results indicate that the biodegradation products are potentially as toxic as PBAT. This might explain why biodegradation products alter the photosynthetic system of plants and inhibit their growth. From this and other previous investigations, we can think that biodegradable plastics could represent a potential environmental risk. Methods: All DFT computations were performed using the Gaussian16 at M062x/6–311 + g(2d,p) level of theory without symmetry constraints. Electro-donating (ω-) and electro-accepting (ω +) powers were used as response functions. [ABSTRACT FROM AUTHOR]

Microplastics and heavy metals are two different classes of pollutants that are often present in aquatic systems. However, the interaction between these two pollutants is poorly understood in freshwater systems. This research has examined the sorption of cadmium(II) ions onto polyethylene microplastic (PEMP) under freshwater conditions. The scanning electron microscope, X-ray diffraction, and Fourier transform infrared analyses confirmed the existence of different functional groups and the porous nature of the PEMP surface. The influences of physicochemical parameters such as the solution pH, contact time, and initial Cd(II) concentration have been examined. The Langmuir isotherm predicted the Cd(II) sorption capacity by PEMP at pH 5 as 1.37 mg/g. Several isotherm models were utilized, including the Freundlich, Langmuir, and Sips models. The results confirmed that the Sips model has been more appropriate for Cd(II)-PEMP isotherm based on percentage errors and correlation coefficient values. Furthermore, the pseudo-first kinetic model fitted Cd(II)-PEMP more accurately than the pseudo-second kinetic equation. Desorption experiments were conducted to release Cd(II) ions from Cd(II)-bearing PEMP using different chemical agents. The findings showed that using 0.01 M nitric acid resulted in a desorption efficiency exceeding 99.8%. This demonstrates that microplastics loaded with Cd(II) may release Cd(II) ions in highly acidic environments, potentially allowing for the uptake of Cd(II) ions by aquatic organisms in their digestive tracts. [ABSTRACT FROM AUTHOR]

Approximately 99% of plastics produced worldwide were produced by the petrochemical industry in 2019 and it is predicted that plastic consumption may double between 2023 and 2050. The use of biodegradable bioplastics represents an alternative solution to petroleum-based plastics. However, the production cost of biopolymers hinders their real-world use. The use of waste biomass as a primary carbon source for biopolymers may enable a cost-effective production of bioplastics whilst providing a solution to waste management towards a carbon–neutral and circular plastics economy. Here, we report for the first time the production of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) with a controlled molar ratio of 2:1 3-hydroxybutyrate:3-hydroxvalerate (3HB:3HV) through an integrated pre-treatment and fermentation process followed by alkaline digestion of cassava peel waste, a renewable low-cost substrate, through Cupriavidus necator biotransformation. PHBV was subsequently melt blended with a biodegradable polymer, polycaprolactone (PCL), whereby the 30:70 (mol%) PHBV:PCL blend exhibited an excellent balance of mechanical properties and higher degradation temperatures than PHBV alone, thus providing enhanced stability and controllable properties. This work represents a potential environmental solution to waste management that can benefit cassava processing industries (or other crop processing industries) whilst developing new bioplastic materials that can be applied, for example, to packaging and biomedical engineering. [ABSTRACT FROM AUTHOR]

The effectual prevention and control of microplastics (MPs) in an environment is of great significance and a challenging task. The extensive usage and improper disposal of plastic materials increased the quantity of MPs in the surroundings, which poses potential issues for both flora and fauna. A recent survey reported that MPs can easily accumulate in human and animal bodies, which causes several adverse health problems such as inflammation, chronic disease, neurotoxicity, oxidative stress, etc. MPs can also disturb the growth, reproduction, and survival of aquatic organisms, leading to a disruption of the food chain and ecosystem. Moreover, it acts as a toxin carrier and transports them into the biological system, leading to the accumulation of toxic compounds in the food chain that cause biomagnification. Therefore, effective MPs management is crucial to prevent and control the release of MPs into the environment. Strategies such as the 3R principle, public awareness, employing suitable solid waste management, and developing biodegradable alternatives to plastics can partially alleviate the hostile effect of MPs on the environment. However, this kind of strategy has not met the present-day demand to reduce waste MPs completely. In the future, available techniques like membrane filters, ultrasound, electrocoagulation, magnetic separation etc. must be combined with advanced technology like machine learning and artificial intelligence (MLAI) for the best performance to remove MPs. This review provides a source for further improvement for the effective prevention and control of waste MPs generation in an environment for sustainability, which can likely be achieved using appropriate technology. [ABSTRACT FROM AUTHOR]

Accumulation of polyethylene terephthalate (PET) polyester in ecosystems across the globe is a major pollution of concern. Microbial degradation recently generated novel insights into the biodegradation of varieties of plastics. In this study, a PET degrading bacterium Brucella intermedia IITR130 was isolated from a contaminated lake ecosystem at Pallikaranai, Chennai, India. Incubation of the bacterium along with the PET sheet (0.1 mm thickness) for 60 days resulted in 26.06% degradation, indicating a half-life of 137.8 days. Considerable changes in the surface morphology of the PET sheet were found as holes, pits, and cracks on incubation with strain IITR130, as revealed by scanning electron microscopy (SEM). After bacterial treatment of PET, the formation of new functional groups, most notably in the area of 3326 cm−1 suggestive of O–H stretch, leading to carboxylic acid and alcohol as products were suggested by fourier transform infrared (FTIR) analysis. Monomethyl terephthalate (MMT) and terephthalic acid (TPA) were identified by gas chromatography–mass spectrometry (GC–MS) analysis as PET degradation metabolites. Tributyrin clearance assay confirmed the presence of a lipase/esterase enzyme in the strain IITR130. In this study, a degradation pathway for PET by an isolated and identified bacterium Brucella intermedia IITR130 was characterized in detail. [ABSTRACT FROM AUTHOR]

Environmental pollution caused by petrochemical hydrocarbons (HC) and plastic waste is a pressing global challenge. However, there is a promising solution in the form of bacteria that possess the ability to degrade HC, making them valuable tools for remediating contaminated environments and effluents. Moreover, some of these bacteria offer far-reaching potential beyond bioremediation, as they can also be utilized to produce polyhydroxyalkanoates (PHAs), a common type of bioplastics. The accumulation of PHAs in bacterial cells is facilitated in environments with high C/N or C/P ratio, which are often found in HC-contaminated environments and effluents. Consequently, some HC-degrading bacteria can be employed to simultaneously produce PHAs and conduct biodegradation processes. Although bacterial bioplastic production has been thoroughly studied, production costs are still too high compared to petroleum-derived plastics. This article aims to provide a comprehensive review of recent scientific advancements concerning the capacity of HC-degrading bacteria to produce PHAs. It will delve into the microbial strains involved and the types of bioplastics generated, as well as the primary pathways for HC biodegradation and PHAs production. In essence, we propose the potential utilization of HC-degrading bacteria as a versatile tool to tackle two major environmental challenges: HC pollution and the accumulation of plastic waste. Through a comprehensive analysis of strengths and weaknesses in this aspect, this review aims to pave the way for future research in this area, with the goal of facilitating and promoting investigation in a field where obtaining PHAs from HC remains a costly and challenging process. [ABSTRACT FROM AUTHOR]

Plastic pollution has become a global problem since the extensive use of plastic in industries such as packaging, electronics, manufacturing and construction, healthcare, transportation, and others. This has resulted in an environmental burden that is continually growing, which has inspired many scientists as well as environmentalists to come up with creative solutions to deal with this problem. Numerous studies have been reviewed to determine practical, affordable, and environmentally friendly solutions to regulate plastic waste by leveraging microbes' innate abilities to naturally decompose polymers. Enzymatic breakdown of plastics has been proposed to serve this goal since the discovery of enzymes from microbial sources that truly interact with plastic in its naturalistic environment and because it is a much faster and more effective method than others. The scope of diverse microbes and associated enzymes in polymer breakdown is highlighted in the current review. The use of co-cultures or microbial consortium-based techniques for the improved breakdown of plastic products and the generation of high-value end products that may be utilized as prototypes of bioenergy sources is highlighted. The review also offers a thorough overview of the developments in the microbiological and enzymatic biological degradation of plastics, as well as several elements that impact this process for the survival of our planet. [ABSTRACT FROM AUTHOR]

Mulching is a common method increasing crop yield and achieving out-of-season production; nevertheless, their removal poses a significant environmental danger. In this scenario, the use of biodegradable plastic mulches comes up as a solution to increase the sustainability of this practice, as they can be tilled in soil without risk for the environment. In this context, it is important to study the microbial response to this practice, considering their direct involvement in plastic biodegradation. This study evaluated the biodegradation of three commercial mulch residues: one conventional non-biodegradable mulch versus two biodegradable ones (white and black compostable Mater-Bi mulches). The experiment was conducted under three incubation temperatures (room temperature 20–25 °C, 30 °C, and 45 °C) for a 6-month trial using fallow agricultural soil. Soil without plastic mulch residues was used as a control. White mater-bi biodegradable mulch residues showed higher degradation rates up to 88.90% at 30 °C, and up to 69.15% at room temperature. Furthermore, incubation at 45 °C determines the absence of degradation for all types of mulch considered. Moreover, bacterial alpha diversity was primarily influenced by plastic type and temperature, while fungal populations were mainly affected by temperature. Beta diversity was impacted by all experimental variables. Predicted functional genes crucial for degrading complex substrates, including those encoding hydrolases, cutinases, cellobiosidases, and lipases, were derived from 16S rRNA gene sequencing data. Cluster analysis based on predicted enzyme-encoding gene abundance revealed two clusters, mainly linked to sampling time. Finally, core microbiome analysis identified dominant bacterial and fungal taxa in various soil-plastic ecosystems during degradation, pinpointing species potentially involved in plastic breakdown. The present study allows an assessment of how different temperatures affect the degradation of mulch residues in soil, providing important insights for different climatic growing zones. It also fills a gap in the literature by directly comparing the effects of biodegradable and polyethylene mulches on soil microbial communities. [ABSTRACT FROM AUTHOR]

Pyrolytic synergistic interactions, in which the production of pyrolyzates is enhanced or inhibited, commonly occur during the co-pyrolysis of different polymeric materials, such as plastics and biomass. Although these interactions can increase the yield of desired pyrolysis products under controlled degradation conditions, the desired compounds must be separated from complex pyrolyzates and further purified. To balance these dual effects, this study was aimed at examining pyrolytic synergistic interactions during slow heating co-pyrolysis of biodegradable plastics including polylactic acid (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexaoate) (PHBH) and petroleum-based plastics including high-density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS). Comprehensive investigations based on thermogravimetric analysis, pyrolysis–gas chromatography/mass spectrometry, and evolved gas analysis-mass spectrometry revealed that PLA and PHBH decompose at lower temperatures (273–378 °C) than HDPE, PP, and PS (386–499 °C), with each polymer undergoing independent decomposition without any pyrolytic interactions. Thus, the independent pyrolysis of biodegradable plastics, such as PLA and PHBH, with common plastics, such as HDPE, PP, and PS, can theoretically be realized through temperature control, enabling the selective recovery of their pyrolyzates in different temperature ranges. Thus, pyrolytic approaches can facilitate the treatment of mixed biodegradable and common plastics. [ABSTRACT FROM AUTHOR]

Microplastic particles appear in great abundance and variety in freshwater ecosystems across the globe, spanning lakes and rivers, with increasingly frequent exposure of aquatic organisms. Studies on the mechanisms of any effects of plastic particles are still scarce, particularly in relation to the regenerative capacity of biota, for which there is no established model organism; however, planaria have shown sensitivity for assessing these risks to the aquatic environment. Thus, the present study aimed to investigate the behavioral and regeneration responses of the freshwater planaria Girardia tigrina exposed to polyethylene (PE) microplastics (MPs) incorporated into their food source. The greatest effect was observed on planarian regeneration, which was manifested at 10 μg/mg liver. Planaria reproduction and fertility were affected at 50 μg/mg liver; however, planaria locomotion was not affected at the concentrations evaluated. Mid-infrared absorption spectroscopy (FT-IR) was used to identify the constituent polymers, and ingestion of the polyethylene microplastic by the planaria was confirmed by infrared spectroscopy. The results highlight the potential adverse effects of exposure to polyethylene microplastic and show that the reproductive behavior and regeneration of a freshwater organism can be indicators of toxicity resulting from environmental pollution. [ABSTRACT FROM AUTHOR]

Virgin and environmentally aged polypropylene (PP) micropowders (V-PP and E-PP, respectively) were used as reference microplastics (MPs) in comparative photo- and thermo-oxidative ageing experiments performed on their mixtures with a natural ferrous sand (NS) and with a metal-free silica sand (QS). The ferrous NS was found to catalyze the photo-oxidative degradation of V-PP after both UV and simulated solar light irradiation. The catalytic activity in the V-PP/NS mixture was highlighted by the comparatively higher fraction of photo-oxidized PP extracted in dichloromethane, and the higher carbonyl index of the bulk polymer extracted with boiling xylene, when compared with the V-PP/QS mixture. Similarly, NS showed a catalytic effect on the thermal degradation (at T = 60 °C) of E-PP. The results obtained indicate that, under suitable environmental conditions (in this case, an iron-containing sediment or soil matrix, combined with simulated solar irradiation), the degradation of some types of MPs could be much faster than anticipated. Given the widespread presence of iron minerals (including the magnetite and iron-rich serpentine found in NS) in both coastal and mainland soils and sediments, a higher than expected resilience of the environment to the contamination by this class of pollutants is anticipated, and possible routes to remediation of polluted natural environments by eco-compatible iron-based minerals are envisaged. [ABSTRACT FROM AUTHOR]

Platforms are structures built by coypus for various purposes, such as reproduction, resting, and thermoregulation. In a coastal wetland of central Italy, during a study aimed at investigating the characteristics of coypu's platforms, it was recorded, for the first time worldwide, the presence of plastic in these structures. Through a transect survey, we censused 83 platforms, among which three (3.61%) were found with presence of macro- and megaplastics (polystyrene, polypropylene, and low-density polyethylene in film form; polyester, polyamide, and expanded polystyrene in fragments). Through the FTIR spectra, it was possible to highlight the degradation of the polymeric materials. To stimulate possible in-depth investigations at the level of the food chain (e.g., coypu predators, including canids) in wet habitats, we discussed possible causes and implications of plastic presence in coypus' nest structures. [ABSTRACT FROM AUTHOR]

With the growing global demand for biodegradable plastics, the hydrogenation of dimethyl maleate (DMM) to produce 1,4-butanediol (BDO), raw materials for poly(butylene succinate), has become one of the hot spots in chemical industry. In this work, we synthesized a series of Cu@C/ZnO–Sx catalysts by the method of sorbitol modification for the liquid-phase hydrogenation of DMM. The modification with appropriate sorbitol led to a decoration of carbon on catalyst surface, which improved the copper dispersion and Cu+/(Cu0 + Cu+) molar ratio in the Cu@C/ZnO–S0.08 catalyst. The carbon decoration not only promoted the formation of more copper species having stronger interaction with ZnO, but also enhanced the absorption of ester on catalyst surface. These distinctive properties contributed to the high performance of the Cu@C/ZnO–S0.08 catalyst in DMM hydrogenation, achieving an excellent BDO yield of 98.4% and superior reusability. The insights into the roles of sorbitol modification could give valuable guidance to the further design of high performance catalysts for esters hydrogenation. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) is known for its excellent overall properties and is widely used as a degradable material. However, PLA has poor toughness due to its inherent brittleness and low ductility. Poly(butylene adipate-co-butylene terephthalate) (PBAT) has good toughness and can be used to toughen PLA, while the poor compatibility between the two materials leads to ineffective toughening of PLA by PBAT, which needs to be modified by adding compatibilizers during processing. In this study, high-toughness PLA-based blends were prepared by in-situ polymerization using lactide as the reactive monomer and PBAT as the toughening agent, with the addition of industrial-grade epoxy oligomers ADR and PLA-PBAT-PLA triblock copolymers as solo or synergistic compatibilizers, to investigate the effects of ADR and PLA-PBAT-PLA on the compatibility and properties of PLA and PBAT. The inclusion of compatibilizers enhanced the interfacial bonding between PLA and PBAT and boosted the toughness of PLA/PBAT blends, and the addition of 0.15 wt% ADR or 0.15 wt% PLA-co-PBAT resulted in the impact strength of PLA/PBAT (75/25) blends reaching 150.09 kJ/m2 and 100.39 kJ/m2, respectively. The epoxy group of ADR reacted with the terminal hydroxyl or terminal carboxyl group of PLA and PBAT to form a chemical bond, which enhanced the melt strength and water absorption. PLA-PBAT-PLA forms a block structure between PLA and PBAT, which improves the fluidity and tensile strength of the blends. These findings provide fundamental data for PLA/PBAT compatibility studies and provide further development for PLA blend modification studies. [ABSTRACT FROM AUTHOR]

This study assessed bioplastics made from different mass proportions of commercial chitosan and banana plant pseudostem-derived hemicelluloses. The bioplastics were prepared by the casting method and characterized for moisture content, water solubility, opacity, water absorption, tensile strength, and thermogravimetric properties. The formulations with hemicelluloses addition showed higher moisture content and water solubility than the chitosan-only bioplastic, the maximum values of these properties (22.3 and 22.4%) were achieved when hemicelluloses were added at the proportion of 10 and 5%, respectively. A positive linear correlation (r = 0.86) was found between added hemicelluloses and opacity, with the highest opacity (1.95 mm−1) achieved in the formulation with the maximum hemicellulose incorporation. The bioplastics containing hemicelluloses exhibited lower swelling (water absorption) than that made only of chitosan, with the formulation featuring the highest hemicelluloses content showed the lowest swelling (229.2%). A negative linear correlation (r = 0.95) was observed between added hemicelluloses and swelling values. The formulation with the highest hemicelluloses content demonstrated statistically significant differences and exhibited the highest tensile strength (18.7 MPa) and Young's modulus (66.1 MPa). Thermogravimetric analysis revealed four stages of mass loss in the bioplastics. Hemicelluloses addition decreased the temperature at maximum mass loss, and the formulation with the lowest hemicelluloses content showed a higher degradation rate than the others. [ABSTRACT FROM AUTHOR]

Biodegradable green composites of poly(butylene succinate) (PBS) and poly(L-lactide) (PLA) fibers were initially melt-blended aiming to obtain balanced comprehensive properties. According to the morphological observations, the PLA fibers were uniformly embedded in the PBS matrix. Rheology measurements suggested that the incorporation of PLA fibers improved the viscoelasticity of PBS melt. The percolation network of PLA fibers was formed at content of 20 wt%. The presence of PLA fibers inhibited the crystallization and reduced the isothermal crystallization rate of PBS in the composites. Moreover, the reinforcing effect of PLA fibers on the PBS matrix was found to be very significant. The storage modulus and tensile modulus of the composite with 30 wt% PLA fibers were 74% and 94% higher than those of neat PBS, respectively. PBS/PLA fiber composites prepared by simple melt blending method displayed the combination of enhanced melt strength and modulus, while maintaining the biodegradability of PBS matrix, which is of great potential for the wider practical application of environmentally friendly polymers. [ABSTRACT FROM AUTHOR]

A method has been developed to quantify PET and PBT microplastics (MPs) based on depolymerization and detection of depolymerization products by gas chromatography-tandem mass spectrometry (GC–MS/MS) without a complex separation process from environmental samples. Under the optimal depolymerization conditions, PET and PBT were efficiently converted to ethylene glycol (78%) and 1,4-butanediol (87%), respectively. Subsequently, the linear curves were constructed between signal intensities of depolymerization products and polymer masses by GC–MS/MS, and the correlation coefficients of PET and PBT were 0.996 and 0.997, respectively. The spiking and recovery experiments of PET and PBT in the environmental samples showed that the recovery was stable in the range 89–100%, and the limit of detection was 4.95 μg and 1.39 μg of PET and PBT, respectively. The method has been proven to be capable of simultaneous identification and quantification of PBT and PET MPs in real environmental water samples without complex separation process, which provided a scheme for the determination of microplastics. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the properties of biodegradable plantable pots made from biomaterials. Specifically, rapeseed straw and cow manure biomaterials were studied here because these biomaterials add nutrients to the soil during their biodegradation and are readily available agricultural by-products. Furthermore, the use of biomaterials helps in replacing the plastic materials which are currently used to make pots and decreases the environmental impact by producing a cleaner product. The physical and mechanical properties of biocomposites pots were investigated and optimized in the present work. The effect of mixing ratio (straw: cow manure) in the composite, straw particle size, and chemical pre-treatments of straw by 1% HCl or 2% NaOH on the physical and mechanical properties of biodegradable pots was investigated. Additionally, the Taguchi method and ANOVA statistical analyses were employed for parameters optimization. The results indicated the straw to cow manure ratio exhibited a significant effect on the compression strength (CS), penetration strength (PS), and water absorption (WA) of pots. While the CS and PS of pots decreased with increasing the ratio of straw from 2 to 10% and increasing the particle size of straw from 1.5 to 3.0 mm, these changes increased the water absorption of pots (126.52–141.21% for 1.5-mm untreated straw). Chemical pre-treatments of straw investigated here resulted in decreased CS and PS of pots. The straw ratio in the straw/manure mixture is the most significant factor affecting the characteristics of biodegradable pots. [ABSTRACT FROM AUTHOR]

Polyethylene terephthalate (PET) is a major component of plastic waste. Enzymatic PET hydrolysis is the most ecofriendly recycling technology. The biorecycling of PET waste requires the complete depolymerization of PET to terephthalate and ethylene glycol. The history of enzymatic PET depolymerization has revealed two critical issues for the industrial depolymerization of PET: industrially available PET hydrolases and pretreatment of PET waste to make it susceptible to full enzymatic hydrolysis. As none of the wild-type enzymes can satisfy the requirements for industrialization, various mutational improvements have been performed, through classical technology to state-of-the-art computational/machine-learning technology. Recent engineering studies on PET hydrolases have brought a new insight that flexibility of the substrate-binding groove may improve the efficiency of PET hydrolysis while maintaining sufficient thermostability, although the previous studies focused only on enzymatic thermostability above the glass transition temperature of PET. Industrial biorecycling of PET waste is scheduled to be implemented, using micronized amorphous PET. Next stage must be the development of PET hydrolases that can efficiently degrade crystalline parts of PET and expansion of target PET materials, not only bottles but also textiles, packages, and microplastics. This review discusses the current status of PET hydrolases, their potential applications, and their profespectal goals. Key points: • PET hydrolases must be thermophilic, but their operation must be below 70 °C • Classical and state-of-the-art engineering approaches are useful for PET hydrolases • Enzyme activity on crystalline PET is most expected for future PET biorecycling [ABSTRACT FROM AUTHOR]

In recent decades, synthetic plastics have posed a significant environmental threat due to their non-biodegradability. Research is being carried out to find alternative biodegradable sources similar to petroleum plastics but with a lower environmental impact than petroleum plastics. Solution casting was utilized to fabricate the blended films of poly(vinyl alcohol) (PVA)/cellulose acetate(CA)/starch with varying ratios with subsequent testing of their biodegradability using amylase and cellulase enzymes. Before and after enzymatic biodegradability testing, SEM, FTIR, tensile strength, elongation percentage, and swelling of (PVA/CA):(Starch) blended films were investigated. The optimized mechanical properties tensile strength appear at the ratio of (PVA/CA):(Starch) 1:1 was 37.17 ± 1.04 MPa. Using both amylase and cellulase enzymes at the same blend of the polymer best biodegradability that resulted in releasing 131.5 mg/dl of glucose units. The results suggest that (PVA/CA):(Starch) films blended in a ratio of 1:1 can replace petroleum-based plastics and become a green alternative. [ABSTRACT FROM AUTHOR]

Considerable interest in food packaging research has been prompted by the rising environmental impact of waste, customer awareness for readily accessible foods with extended shelf life, and ecological consciousness about the scarcity of natural resources. The utilization of plastic-based food packaging has resulted in a significant environmental concern due to the accumulation of substantial quantities of plastic in the surrounding areas. Research efforts are being motivated by ecological and health considerations in the pursuit of developing biodegradable films. Besides, poly(lactic acid) (PLA) has been suggested as a possible substitute for petroleum-based polymers because of its sustainability, simple accessibility, and biodegradability. PLA is a biodegradable plastic made from sugar beet or maize starch that may be fermented by bacteria to generate material with desirable qualities like transparency and rigidity. However, there is a need for further improvement in certain properties of PLA, such as flexibility, toughness, permeability, and thermal properties. One potential approach for enhancing these attributes involves the integration of nano-reinforcement. The utilisation of nanocellulose derived from biomass has garnered significant interest in recent times owing to its renewable nature, ability to biodegrade, impressive mechanical strength, low density, and considerable economic worth. In this study, we present a comprehensive overview of the most up-to-date methods for synthesising nanocellulose and its use as a filler material in the manufacture of PLA nanocomposites for food packaging. In addition, this study examines the emerging challenges and potential advantages associated with the utilization of PLA biocomposites incorporated with nanocellulose in the food packaging sector. [ABSTRACT FROM AUTHOR]

Electrochemically converting CO2 into value-added chemicals is a promising approach to mitigate anthropogenic carbon emissions, yet largely limited to short-chained C1–C3 products. Herein, we demonstrate a tandem artificial synthesis of biodegradable polyhydroxybutyrate (PHB) plastic from CO2 building blocks. Batch synthesis of defects-enriched Bi catalyst is firstly demonstrated by plasma bombardment and following in situ electrochemical reduction, which delivers a HCOOH Faradaic efficiency above 80% at tunable concentration from 2 to 250 mM, an energy efficiency up to 41%, and a single-pass carbon conversion efficiency up to 60%. Annular dark field and second electron microscopic analysis, density functional theory (DFT) calcualtions, coupled with H-type and solid-state electrolyzer assessments, point out the vital role of defective and/or stepped Bi surface sites in promoting CO2-to-HCOOH conversion. Thereafter, as-synthesized high-purity HCOOH is used as the sole carbon source for C-chain growth within microbial fermentation reactor with Ralstonia eutropha, where activated formate dehydrogenase and increased metabolites related to Calvin–Benson–Bassham cycle are found to be responsible for the enhanced polyester accumulation. [ABSTRACT FROM AUTHOR]

Microplastics, an emerging contaminant, are widespread in oceans around the world, and rivers are the key conveyors of these pollutants into the oceans. There exists a dearth of available data pertaining to seasonal fluctuation, spatial distribution and risk assessment of microplastics in rivers extending from upper reaches to the lower reaches. The collection of such data is of utmost importance for the purpose of formulating beneficial management strategies for riverine microplastics. In order to bridge this research gap, an investigation was made in the Periyar River in Kerala, India, which is exposed to anthropogenic stress and is at risk of microplastic pollution. A total of eighteen sites (six sites each from downstream, midstream and upstream) along the 244 km of the river were investigated across three seasons in a year. The study revealed a discernible pattern in the spatial distribution of microplastic concentrations, wherein there was a rise in abundance from the upstream to midstream and then a sudden increase of abundance along the downstream regions towards the lower reaches. The highest mean microplastic abundance of 124.95 items/L was obtained during the monsoon season followed by post-monsoon season i.e. 123.21 items/L and pre-monsoon i.e. 120.50 items/L. The predominant forms of microplastics were found to be fibres, fragments and filaments. Most prevalent polymer types acquired were polyethylene (PE) and polypropylene (PP). Pollution hazard index (PHI) and pollution load index (PLI) were also evaluated to assess the water quality of this river. The findings of this study conclude that the Periyar River is polluted with microplastics throughout its course and offer significant insights into the detection of microplastic origins in river systems and lend support to the implementation of potential measures aimed at mitigating their impact. [ABSTRACT FROM AUTHOR]

Over the last years, bio-based and biodegradable alternatives have gained considerable attention both of academic and of packaging industrial communities, driven by recent legislation and increasing awareness concerning environmental issues related to traditional plastic. However, it is often observed that packaging products made from bioplastics do not exhibit comparable performance to those produced using common non-biodegradable ones. The presence of long chain branching improves the processing behavior under elongational flow and, then, the filmability of low viscosity polymers such as polyesters. In this work it has been demonstrated that the presence of long chain branching in a bio-co-polyester, induced by the use of pentaerythritol in the synthesis a of poly(butylene adipate-co-butylene terephthalate), is able to dramatically change the rheological behavior of the linear chain polyester improving its filmability. The addition of branching lead to an increase of the elastic modulus and the tensile strength in branched polyester films if compared to the linear ones, while the elongation at break decreased. This is due to the answer of the branched polyester to the non-isothermal elongational flow that allows a better orientation of the macromolecules of the branched polyester. The film obtained with the branched polyester showed a decrease in clarity and a slight increase in haze if compared to linear one due to differences in the morphology of the two samples. [ABSTRACT FROM AUTHOR]

Biodegradable polymers for food applications have emerged as a sustainable alternative to reduce plastic waste. In this work, compostable films based on blends of poly(ε-caprolactone) (PCL) and thermoplastic gliadins (TPG) were developed for packaging applications. Firstly, gliadins were extracted from wheat gluten and plasticized with glycerol. Then, PCL/TPG films were prepared by cast-extrusion processing at pilot scale and samples were characterized in terms of their structural, morphological, thermal, mechanical, barrier and optical properties. The addition of TPG increased the glass transition temperature (Tg) of PCL, reduced the oxygen permeability at 0% and 50% relative humidity values, and improved the seal strength properties of the films, having a minimal effect on the thermal stability, transparency, and the high stretchability characteristic of PCL. On the other hand, the presence of gliadins led to more water sensitive materials, resulting in a slight increase in the water vapor permeability. Finally, the home-compostability assessment of the films revealed that the presence of gliadins accelerated the aerobic biodegradation and the disintegration with respect to pristine PCL film, thus, showing the potential interest of the developed materials for sustainable packaging applications. [ABSTRACT FROM AUTHOR]

Microplastics pose significant challenges to ecosystems and organisms. They can be ingested by marine and terrestrial species, leading to potential health risks and ecological disruptions. This study aims to address the urgent need for effective remediation strategies by focusing on the biodegradation of microplastics, specifically polyvinyl chloride (PVC) derivatives, using the bacterial strain Bacillus albus. The study provides a comprehensive background on the accumulation of noxious substances in the environment and the importance of harnessing biodegradation as an eco-friendly method for pollutant elimination. The specific objective is to investigate the enzymatic capabilities of Bacillus albus, particularly the alpha/beta hydrolases (ABH), in degrading microplastics. To achieve this, in-silico studies were conducted, including analysis of the ABH protein sequence and its interaction with potential inhibitors targeting PVC derivatives. Docking scores of − 7.2 kcal/mol were obtained to evaluate the efficacy of the interactions. The study demonstrates the promising bioremediation prospects of Bacillus albus for microplastics, highlighting its potential as a key player in addressing microplastic pollution. The findings underscore the urgent need for further experimental validation and practical implementation of Bacillus albus in environmental remediation strategies. [ABSTRACT FROM AUTHOR]

The effective disposal of plastic waste has been a key global research issue. In this regard, the pyrolysis of plastic wastes seems to be an effective technique as this process is capable of producing fuel-grade oils. In the present work, the thermal decomposition of polyethylene (PE), polystyrene (PS), and their mixture (PS/PE) was investigated with an aim to enhance yields of liquid fractions with fuel-grade quality. The effect of operating parameters on the end products was studied. The obtained maximum liquid yields for polyethylene (PE) and polystyrene (PS) samples were 96.3 wt.% at 380 °C and 88.1 wt.% at 415 °C, respectively. For the PS/PE (50/50%) sample, the maximum conversion was 93.2 wt.% at 420 °C. Char yield was observed negligible (1–3 wt.%) at low reaction temperatures (350–420 °C). PE samples showcased a sharp initial decrease from 1.8 wt.% at 350 °C to 0.7 wt.% at 415 °C. PS also presented a similar trend; whereas, PS/PE sample was observed with 3.1 wt.% char at 350 °C that decreased to 1.4 wt.% at 420 °C. PE oil samples showed the presence of 1-alkenes and n-alkanes compounds in abundance, with carbon numbers in the range of C7 to C28. PS oil fractions comprised of toluene, ethylbenzene, and styrene in higher proportions of around 42%. On the other hand, PS/PE oil fractions mostly constituted the aliphatic hydrocarbons embracing both alkanes and alkenes with carbon numbers C12 to C22. Comparative assessment reveals that for PE oil fractions from the autoclave reactor are 44.4% and 90.2% higher than the same with fluidized bed and microwave-assisted reactors, whereas for PS oil fractions the values were marginally higher. [ABSTRACT FROM AUTHOR]

Agricultural solid waste (ASW) is a serious concern globally, specifically in agricultural countries like India, China, Japan, Indonesia, Malaysia, etc. A lot of agricultural waste like the remain of crop plants, peels, leaves, corn cob, decayed crops, etc., is produced directly or indirectly every year affecting the environment and is not appropriately managed. Therefore, to overcome this problem, there is a need to develop waste redemption techniques to transform solid waste into value-added products. The wastes are generally rich in carbohydrates, lipids, proteins, and many other organic and inorganic constituents. This composition allows us to produce numerous value-added products like livestock feed, bio-preservatives, biofuels, biofertilizers, single-cell proteins, nanoparticles, biodegradable plastic, chitosan, collagen, and antibodies. Additionally, various start-ups leading to new beneficial products from agricultural solid waste should be promoted. This review intends to explore the sources of agricultural solid waste generation and to provide a solution to manage the waste through modern technologies, saving the environment and boosting a country's economy. The outcome of our study will lead toward a sustainable approach to waste management as we have comprises the most innovative and successful working models in one place. This newly developed technique will help to achieve the greater goal of sustainable development. [ABSTRACT FROM AUTHOR]

Commercially pure green Al powder compacts were subjected to single-pass friction stir processing (FSP) with different tool rotational speeds. The effect of temperature and strain rate on the microstructural evolution during FSP was analyzed. The evolution of texture and different types of grain boundaries (GBs) (i.e., misorientation of GBs between 2° to 5°, 5° to 15°, 15° to 40° and 40° to 65°) were analyzed to find out the mechanism behind the microstructural evolution in the samples. At a lower strain rate, the restoration mechanism is mostly through extended recovery or continuous dynamic recrystallization. At a higher strain rate, with increased temperature, concomitant evolution of rotated cube component is noticed. Texture weakening with an increase in rotation speed and the presence of rotated cube component suggests the presence of other recrystallization mechanisms than continuous dynamic recrystallization. [ABSTRACT FROM AUTHOR]

The joint impact of tadalafil (Cilais) as a pharmaceutical residue and microplastics on fish is not well comprehended. The current study examined haematological, biochemical, and antioxidant parameters, along with immunohistochemical and histological indications in tilapia (Oreochromis niloticus) after being exposed to tadalafil, polyethylene microplastics (PE-MPs), and their mixtures for 15 days. The fish were distributed into 1st group control group (The fish was maintained in untreated water without any supplements); 2nd group exposed to 10 mg/L PE-MPs;3rd group exposed to 20 mg/l tadalafil (Cilais); 4th group exposed to 20 mg/l tadalafil (Cilais) + 10 mg/LPE-MPs (in triplicate). The levels of creatinine, uric acid, glucose, AST, ALT, and albumin in fish treated with tadalafil alone or in combination with PE-MPs were significantly higher than those in the control group. Fish exposed to PE-MPs, tadalafil, and tadalafil plus PE-MPs showed significantly lower levels of RBCs, Hb, Ht, neutrophils, and lymphocytes compared to the control group. Serum levels of total antioxidant capacity and reduced glutathione (GSH) were notably lowered in fish groups subjected to PE-MPs, tadalafil, and tadalafil + PE-MPs combinations in comparison to the control group. Malondialdehyde (MDA) serum levels were notably elevated in fish groups subjected to PE-MPs, tadalafil, and tadalafil + PE-MPs combinations compared to the control group. The most severe impact was observed in the tadalafil + PE-MPs combination group. Interleukin-6 (IL-6) levels were significantly increased in liver tissues following exposure to both tadalafil and microplastics compared to tissues exposed to only one substance or the control group. Changes in the gills, liver, and renal tissues were seen following exposure to PE-MPs, tadalafil, and tadalafil + PE-MPs combination in comparison to the control group of fish. Ultimately, the mixture of tadalafil and PE-MPs resulted in the most detrimental outcomes. Tadalafil and PE-MPs exhibited showed greater adverse effects, likely due to tadalafil being absorbed onto PE-MPs. [ABSTRACT FROM AUTHOR]

Advanced recycling offers a unique opportunity for the circular economy, especially for mixed and contaminated plastics that are difficult to recycle mechanically. However, advanced recycling has barriers such as poor selectivity, contaminant sensitivity, and the need for expensive catalysts. Reported herein is a simple yet scalable methodology for converting mixed polyethylene (high-density and low-density polyethylene recycled polyethylene) into upcycled waxes with up to 94% yield. This high yield was possible by performing the reaction at a mild temperature and was enabled by using inexpensive and reusable table salt. Without table salt, in otherwise identical conditions, the plastic remained essentially undegraded. These upcycled waxes were used as prototypes for applications such as water- and oil-resistant paper, as well as rheology modifiers for plastics. Their performance is similar to that of commercial wax as well as rheology modifiers. A preliminary economic analysis shows that the upcycled waxes obtained by this table salt-catalyzed approach offer three times more revenue than those reported in the literature. This pioneering discovery opens the door for a circular economy of plastics in general and polyolefins in particular. [ABSTRACT FROM AUTHOR]

Background: Plastic is generating global pollution and the replacement such as bioplastic has been developed to mitigate the pollution. To this end, the fate, transformation and pathway of bioplastics need more research. For example, the fragmentation of bioplastic can release small debris that can be categorised as microplastics, which is tested herein by taking an example of a compostable plastic that is used as a bin bag on our kitchen table to collect the food residues. Results: First, we employ matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) to identify the main components of the bioplastic bag as polymer and starch. Next, we use Raman imaging to monitor the stability under laser illumination, in an oven at ~ 60 °C for ~ 2 weeks, or in the presence of tap water for half a year. Basically, the compostable plastic is stable under these conditions. Thirdly, however, once used as table-bin bag with involvement of food residues, within ~ 1 week, the bioplastic bag is broken and biodegraded to release debris. The derivate surface groups are effectively monitored and directly visualised via Raman imaging, and cross-checked with scanning electron microscope (SEM). The yielded small molecule such as formic acid is also identified, along with the released debris of microplastics, with the help of on-site extraction of the fragmented sample and imaging analysis algorithm of the hyper spectrum. Conclusions: After one week, the bag in the waste bin fragments, releasing a significant amount of debris. This could pose a functional issue if users intend to use the bag for at least a week, and could become a potential environmental problem if the waste is dispersed uncontrollably. In general, further research is needed to potentially distinguish the persistent conventional microplastics from the bioplastic fragments, to effectively mitigate the plastic pollution. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are gaining global attention in recent years due to its widespread distribution and potential health impacts. The present study focuses on the distribution and characterisation of microplastics in the sediments and its transfer into the organisms living in Kavvayi and Kumbla backwaters of Northern Malabar region, Kerala, India. MP isolation procedures including density separation, organic matter digestion, and membrane filtration followed by visual and spectral analyses using optical microscope and confocal Raman spectroscopy have been utilised for the microplastic evaluation. Microplastics of size range up to 1 μm was analysed, and the presence of MPs was detected in all samples with an average abundance of 99.5 ± 69.43 particles/kg and 96.57 ± 29.96 particles/kg in Kavvayi and Kumbla backwaters respectively. Raman spectral analysis confirmed that almost 50% of MPs to be synthetic elastomers with the remaining half encompassed by polyamide, polyethylene, polyester, polyurethane, and polypropylene. Higher abundance of MPs in the edible aquatic organisms like clams, prawns, and fishes confirmed the transfer of MP from the environment into living organisms envisages the need of further investigation on toxicological impacts and management strategies. [ABSTRACT FROM AUTHOR]

With a growing population of about 7.8 billion, humans are generating tons of waste in the form of non-biodegradable plastics on a daily basis that ends up in landfills and oceans. The introduction of packaging has been a blessing to mankind by facilitating the ease of convenience in transportation, delivery and general usage. The downside, however, is that majority of the packaging currently available is harmful to the environment and takes thousands of years to decay. This paper discusses the use of chitosan from shrimp shells and other marine animals' exoskeleton waste in food packaging industries. Chitosan extracted from marine organisms is modulated in the form of packaging material. Compared to conventional packaging, chitosan films are 73.4% biodegradable in soil under laboratory conditions whereas 100% degraded in an open field. Chitosan with metal oxides, essential oils, natural extracts, proteins and other polymers show enhanced tensile strength, water vapor permeability, oxygen and ultraviolet barrier. Chitosan and composite film show antimicrobial activity against gram positive and negative bacteria. Comparative approaches on environmental impacts between conventional plastics and chitosan films are enlightened, thereby highlighting the importance of natural polymers as packaging films that are considered economic based on the addition of additives. [ABSTRACT FROM AUTHOR]

The rising use of plastic results in an appalling amount of waste which is scattered into the environment. One of these plastics is PET which is mainly used for bottles. We have identified and characterized an esterase from Streptomyces, annotated as LipA, which can efficiently degrade the PET-derived oligomer BHET. The Streptomyces coelicolorScLipA enzyme exhibits varying sequence similarity to several BHETase/PETase enzymes, including IsPETase, TfCut2, LCC, PET40 and PET46. Of 96 Streptomyces strains, 18% were able to degrade BHET via one of three variants of LipA, named ScLipA, S2LipA and S92LipA. SclipA was deleted from S. coelicolor resulting in reduced BHET degradation. Overexpression of all LipA variants significantly enhanced BHET degradation. All variants were expressed in E. coli for purification and biochemical analysis. The optimum conditions were determined as pH 7 and 25 °C for all variants. The activity on BHET and amorphous PET film was investigated. S2LipA efficiently degraded BHET and caused roughening and indents on the surface of PET films, comparable to the activity of previously described TfCut2 under the same conditions. The abundance of the S2LipA variant in Streptomyces suggests an environmental advantage towards the degradation of more polar substrates including these polluting plastics. A comprehensive study on the identification and characterization of PETase-like enzymes in Streptomyces indicates the presence of strain specific variants of a conserved BHET-degrading esterase. [ABSTRACT FROM AUTHOR]

The current study focuses on the engine performance and emission analysis of a 4-stroke compression ignition engine powered by waste plastic oil (WPO) obtained by the catalytic pyrolysis of medical plastic wastes. This is followed by their optimization study and economic analysis. This study demonstrates the use of artificial neural networks (ANN) to forecast a multi-component fuel mixture, which is novel and reduces the amount of experimental effort required to determine the engine output characteristics. The engine tests were conducted using WPO blended diesel at various proportions (10%, 20%, 30% by volume) to acquire the required data for training the ANN model, which enables better prediction for the engine performance by making use of the standard back-propagation algorithm. Considering supervised data obtained from repeated engine tests, an artificial intelligence-based model of ANN was designed to select different parameters of performance and emission as output layers; at the same time, engine loading and different blending ratios of the test fuels were taken as the input layers. The ANN model was built up making use of 80% of testing outcomes for training. The ANN model forecasted engine performance and exhaust emission with regression coefficients (R) at 0.989–0.998 intervals and a mean relative error from 0.002 to 0.348%. Such results illustrated the effectiveness of the ANN model for estimating emissions and the performance of diesel engines. Moreover, the economic viability of the use of 20WPO as an alternative to diesel was justified by thermo-economic analysis. [ABSTRACT FROM AUTHOR]

The article describes a green and efficient synthesis method for pyrano[2,3-c]-pyrazoles, employing DL-alpha-tocopherol methoxypolyethylene glycol succinate solution (TPGS-750-M) as a green and biodegradable surfactant in water. The utilization of water as a reaction medium and TPGS-750-M as a surfactant obviates the necessity for organic solvents, thereby enhancing the environmental sustainability of the synthesis. The compounds synthesized using this novel method was characterized using various spectroscopic techniques, including 1H-NMR, 13C-NMR, and mass spectrometry. [ABSTRACT FROM AUTHOR]