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Biodegradation Jun 2024To date, enumerable fungi have been reported to participate in the biodegradation of several notorious plastic materials following their isolation from soil of... (Review)
Review
To date, enumerable fungi have been reported to participate in the biodegradation of several notorious plastic materials following their isolation from soil of plastic-dumping sites, marine water, waste of mulch films, landfills, plant parts and gut of wax moth. The general mechanism begins with formation of hydrophobin and biofilm proceding to secretion of specific plastic degarding enzymes (peroxidase, hydrolase, protease and urease), penetration of three dimensional substrates and mineralization of plastic polymers into harmless products. As a result, several synthetic polymers including polyethylene, polystyrene, polypropylene, polyvinyl chloride, polyurethane and/or bio-degradable plastics have been validated to deteriorate within months through the action of a wide variety of fungal strains predominantly Ascomycota (Alternaria, Aspergillus, Cladosporium, Fusarium, Penicillium spp.). Understanding the potential and mode of operation of these organisms is thus of prime importance inspiring us to furnish an up to date view on all the presently known fungal strains claimed to mitigate the plastic waste problem. Future research henceforth needs to be directed towards metagenomic approach to distinguish polymer degrading microbial diversity followed by bio-augmentation to build fascinating future of waste disposal.
Topics: Plastics; Polyurethanes; Polymers; Polyethylene; Biodegradation, Environmental; Alternaria
PubMed: 37665521
DOI: 10.1007/s10532-023-10053-2 -
Environmental Science and Pollution... Feb 2024Increasing pollution of plastic waste is one of the major global environmental threats, deteriorating our land, water and air. The shift towards biobased, biodegradable... (Review)
Review
Increasing pollution of plastic waste is one of the major global environmental threats, deteriorating our land, water and air. The shift towards biobased, biodegradable and compostable plastics is considered a green alternative to petroleum-based plastic due to its renewable source or biodegradability. However, there is a misconception about biodegradable plastics and their degradability and behaviour after service life. Biobased, biodegradable and compostable plastics offer various benefits such as less carbon footprint, energy efficiency, independence and eco-safety. On the other hand, there are some disadvantages such as higher cost, limited recycling, misuse of terms and lack of legislation. Also, there is an urgent need for comparable international standard methods to define these materials as biodegradable material, or biocompostable material. There are some standards currently available, however, an in-depth detail and explanation of these standards is still missing. This review outlines the basic definition and chemical structure of biobased, biodegradable and compostable plastics; describes the degradation pathways of biodegradable and compostable plastics; and summarises current key applications of these materials together with possible future applications in different industries. Finally, strategies are developed for minimising the environmental impacts and the need for future research is proposed.
Topics: Biodegradable Plastics; Recycling; Biodegradation, Environmental; Industry; Carbon Footprint; Plastics
PubMed: 38177642
DOI: 10.1007/s11356-023-31689-w -
Marine Pollution Bulletin Nov 2023Marine microplastics generated by wear and tear of bottom trawls and demersal seines during their service life is a growing environmental concern that requires immediate...
Marine microplastics generated by wear and tear of bottom trawls and demersal seines during their service life is a growing environmental concern that requires immediate attention. In Norway, these fishing gears account for more than 70 % of the landings of demersal fish species, but they are also the leading sources of microplastics generated by fisheries. Because these two fishing gears are widely used around the world, replacing fossil-based non-degradable plastics with more abrasion-resistant materials, including biodegradable polymers, should contribute to the reduction of marine litter and its associated environmental impacts. However, the lack of available recycling techniques and the need for separate collection of biodegradable polymers means that these materials will most likely be incinerated for energy recovery, which is not favourable from a circular economy perspective. Nonetheless, from an environmental perspective the use of such biodegradable polymers in demersal fisheries could still be a better alternative to standard polymer materials.
Topics: Animals; Plastics; Microplastics; Fisheries; Environmental Pollution; Polymers
PubMed: 37813057
DOI: 10.1016/j.marpolbul.2023.115634 -
PloS One 2023The etiology of autism spectrum (ASD) and Attention Deficit/Hyperactivity (ADHD) disorders are multifactorial. Epidemiological studies have shown associations with...
BACKGROUND
The etiology of autism spectrum (ASD) and Attention Deficit/Hyperactivity (ADHD) disorders are multifactorial. Epidemiological studies have shown associations with environmental pollutants, such as plasticizers. This study focused on two of these compounds, the Bisphenol-A (BPA) and Diethylhexyl Phthalate (DEHP). The major pathway for BPA and DEHP excretion is via glucuronidation. Glucuronidation makes insoluble substances more water-soluble allowing for their subsequent elimination in urine.
HYPOTHESIS
Detoxification of these two plasticizers is compromised in children with ASD and ADHD. Consequently, their tissues are more exposed to these two plasticizers.
METHODS
We measured the efficiency of glucuronidation in three groups of children, ASD (n = 66), ADHD (n = 46) and healthy controls (CTR, n = 37). The children were recruited from the clinics of Rutgers-NJ Medical School. A urine specimen was collected from each child. Multiple mass spectrometric analyses including the complete metabolome were determined and used to derive values for the efficiency of glucuronidation for 12 varied glucuronidation pathways including those for BPA and MEHP.
RESULTS
(1) Both fold differences and metabolome analyses showed that the three groups of children were metabolically different from each other. (2) Of the 12 pathways examined, only the BPA and DEHP pathways discriminated between the three groups. (3) Glucuronidation efficiencies for BPA were reduced by 11% for ASD (p = 0.020) and 17% for ADHD (p<0.001) compared to controls. DEHP showed similar, but not significant trends.
CONCLUSION
ASD and ADHD are clinically and metabolically different but share a reduction in the efficiency of detoxification for both BPA and DEHP with the reductions for BPA being statistically significant.
Topics: Humans; Child; Diethylhexyl Phthalate; Plasticizers; Neurodevelopmental Disorders
PubMed: 37703261
DOI: 10.1371/journal.pone.0289841 -
International Journal of Biological... Feb 2024Chitosan-based bioplastics are attractive biodegradable alternatives to petroleum-derived plastics. However, optimizing the properties of chitosan materials to fit a...
Chitosan-based bioplastics are attractive biodegradable alternatives to petroleum-derived plastics. However, optimizing the properties of chitosan materials to fit a particular application or obtain a desired property is not a trivial feat. Here, we report the tunability of glycerol-plasticized chitosan films with the addition of boric acid. In combination, glycerol and boric acid form neutral complexes that alter the hydrogen-bonding face of the plasticizer and ultimately limit glycerol's ability to plasticize chitosan. Thus, we found that chitosan films containing glycerol-boric acid complexes were less flexible, had increased thermal transition temperatures, and showed more uniform morphologies. Structural, thermal, mechanical and morphological characterization was performed using ATR-FTIR, TGA and DSC, DMA, and SEM respectively. Molecular-level interactions of the neutral boron complexes and D-glucosamine, the repeat unit of chitosan, were also investigated used NMR and ATR-FTIR. The results of this work demonstrate the necessity of specific hydrogen-bonding interactions between the plasticizer and the polymer for effective plasticization, an important insight into the plasticization mechanism of chitosan films. Furthermore, the formation of complexes with glycerol is a novel and convenient method for tuning the physical properties of chitosan films.
Topics: Chitosan; Plasticizers; Glycerol; Hydrogen; Boric Acids
PubMed: 38262823
DOI: 10.1016/j.ijbiomac.2024.129304 -
Environmental Science. Processes &... Dec 2023The timespans over which different plastics degrade in the environment are poorly understood. This study aimed to rank the degradation speed of five widespread plastic...
The timespans over which different plastics degrade in the environment are poorly understood. This study aimed to rank the degradation speed of five widespread plastic polymers-low density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polylactic acid (PLA) and polyethylene terephthalate (PET)-in terms of their physicochemical properties. Five of the six samples were plastic films with identical dimensions, which allowed the influence of morphology to be excluded, with a polyethylene carrier bag (PEB) tested for comparison. An accelerated weathering chamber was used to photochemically degrade samples over 41 days, with degradation monitored mass loss and changes to carbonyl index, crystallinity and contact angle. The mass loss ranking was PP ≫ LDPE > PEB > PS > PLA > PET. Estimates of the time needed for complete degradation ranged from 0.27 years for PP to 1179 years for PET. Therefore, mass loss in PP proceeded more rapidly than the other polymers, which was unexpected based on previous literature and is plausibly explained by the presence of an unlisted additive which accelerated degradation. Increases in carbonyl index proceeded more rapidly in PP and LDPE than the other polymers tested. However, changes in contact angle and crystallinity did not correspond to the mass loss ranking. Therefore, monitoring the carbonyl index during accelerated weathering trials can indicate which polymers will fragment more quickly. However, alternative approaches are needed to simulate conditions where photooxidation reactions are negligible, such as the ocean floor.
Topics: Plastics; Polyethylene; Polymers; Polystyrenes; Polypropylenes; Polyesters
PubMed: 37882078
DOI: 10.1039/d3em00295k -
Archives of Microbiology Apr 2024Micro- plastics (MPs) pose significant global threats, requiring an environment-friendly mode of decomposition. Microbial-mediated biodegradation and biodeterioration of... (Review)
Review
Micro- plastics (MPs) pose significant global threats, requiring an environment-friendly mode of decomposition. Microbial-mediated biodegradation and biodeterioration of micro-plastics (MPs) have been widely known for their cost-effectiveness, and environment-friendly techniques for removing MPs. MPs resistance to various biocidal microbes has also been reported by various studies. The biocidal resistance degree of biodegradability and/or microbiological susceptibility of MPs can be determined by defacement, structural deformation, erosion, degree of plasticizer degradation, metabolization, and/or solubilization of MPs. The degradation of microplastics involves microbial organisms like bacteria, mold, yeast, algae, and associated enzymes. Analytical and microbiological techniques monitor microplastic biodegradation, but no microbial organism can eliminate microplastics. MPs can pose environmental risks to aquatic and human life. Micro-plastic biodegradation involves fragmentation, assimilation, and mineralization, influenced by abiotic and biotic factors. Environmental factors and pre-treatment agents can naturally degrade large polymers or induce bio-fragmentation, which may impact their efficiency. A clear understanding of MPs pollution and the microbial degradation process is crucial for mitigating its effects. The study aimed to identify deteriogenic microorganism species that contribute to the biodegradation of micro-plastics (MPs). This knowledge is crucial for designing novel biodeterioration and biodegradation formulations, both lab-scale and industrial, that exhibit MPs-cidal actions, potentially predicting MPs-free aquatic and atmospheric environments. The study emphasizes the urgent need for global cooperation, research advancements, and public involvement to reduce micro-plastic contamination through policy proposals and improved waste management practices.
Topics: Humans; Microplastics; Plastics; Biodegradation, Environmental; Industry; Microbiological Techniques; Water Pollutants, Chemical
PubMed: 38558101
DOI: 10.1007/s00203-024-03904-w -
Environmental Toxicology and... Sep 2023Microplastics are present in the environment, in drinking water, in human blood and there is evidence of nanoplastics in tap water. The objective of this work was to... (Review)
Review
Microplastics are present in the environment, in drinking water, in human blood and there is evidence of nanoplastics in tap water. The objective of this work was to analyze the possibility of hemodialysis patients being contaminated by micro and nanoplastics (MNPs) during dialysis treatment. The motivation for this investigation is the fact that hemodialysis patients use about 300-600 L of drinking water per week, which may be contaminated by MNPs. A literature review, a field investigation in a London hospital and an estimation of MNPs intake in patients were carried out. The results showed potential points of risk of contamination of patients by MNPs in hemodialysis. It was also estimated that for a filtration efficiency of 99 % for MNPs, the amount of microplastics that can penetrate the kidneys of patients is 0.0021-3768 particles/week. The assessment concludes that hemodialysis patients are at high risk of MNP contamination.
Topics: Humans; Microplastics; Radar; Plastics; Drinking Water; Renal Dialysis
PubMed: 37604358
DOI: 10.1016/j.etap.2023.104253 -
International Journal of Molecular... Jan 2024Measures to endorse the adoption of eco-friendly biodegradable plastics as a response to the scale of plastic pollution has created a demand for innovative products from... (Review)
Review
Measures to endorse the adoption of eco-friendly biodegradable plastics as a response to the scale of plastic pollution has created a demand for innovative products from materials from Nature. Ionic liquids (ILs) have the ability to disrupt the hydrogen bonding network of biopolymers, increase the mobility of biopolymer chains, reduce friction, and produce materials with various morphologies and mechanical properties. Due to these qualities, ILs are considered ideal for plasticizing biopolymers, enabling them to meet a wide range of specifications for biopolymeric materials. This mini-review discusses the effect of different IL-plasticizers on the processing, tensile strength, and elasticity of materials made from various biopolymers (e.g., starch, chitosan, alginate, cellulose), and specifically covers IL-plasticized packaging materials and materials for biomedical and electrochemical applications. Furthermore, challenges (cost, scale, and eco-friendliness) and future research directions in IL-based plasticizers for biopolymers are discussed.
Topics: Ionic Liquids; Plasticizers; Cellulose; Biopolymers; Chitosan
PubMed: 38338998
DOI: 10.3390/ijms25031720 -
Journal of Insect Physiology Sep 2023Environmental plastic pollution has significantly increased in the recent decades, and severely impacts economies, human and biodiversity health. Plastics are made of...
Environmental plastic pollution has significantly increased in the recent decades, and severely impacts economies, human and biodiversity health. Plastics are made of several chemical additives, including bisphenol and phthalate plasticizers such as bisphenol A (BPA) and Di(2-ethylhexyl)phthalate (DEHP). In some animal species, both BPA and DEHP are known as endocrine disruptor compounds, and can alter physiological and metabolic homeostasis, reproduction, development and/or behavior. To date, the impacts of BPA and DEHP have mainly focused on vertebrates, and to a lesser extent, on aquatic invertebrates. Yet, the few studies which examined the effects of DEHP on terrestrial insects also revealed the impacts this pollutant can have on development, hormone titrations, and metabolic profiles. In particular, it has been hypothesized in the Egyptian cotton leafworm Spodoptera littoralis that the observed metabolic alterations could result from the energetic costs necessary for DEHP detoxification or to the dysregulation of hormonally-controlled enzymatic activities. To get additional insights into the physiological effects of bisphenol and phthalate plasticizers on the moth S. littoralis, larvae were fed with food contaminated by BPA, DEHP, or the mixture of both compounds. Then, activities of four glycolytic enzymes, hexokinase, phosphoglucose isomerase, phosphofructokinase, and pyruvate kinase were measured. BPA and/or DEHP had no effects on the activities of phosphofructokinase and pyruvate kinase. Conversely, BPA-contaminated larvae were characterized by a 1.9-fold increase in phosphoglucose isomerase activity, and BPA + DEHP-fed larvae had highly variable hexokinase activity. Overall, since no disruption of glycolytic enzyme was observed in DEHP-contaminated larvae, our work tended to demonstrate that exposure to bisphenol and DEHP increased the amount of oxidative stress experienced.
Topics: Humans; Animals; Plasticizers; Diethylhexyl Phthalate; Spodoptera; Moths; Pyruvate Kinase; Glucose-6-Phosphate Isomerase; Hexokinase; Larva; Phosphofructokinases
PubMed: 37380125
DOI: 10.1016/j.jinsphys.2023.104533