Degradation Of Plastics Research Articles

The programmed sequence-based oxygenase screening for polypropylene degradation

Enzymatic degradation of plastic is an effective means of plastic recycling and pollution control. However, the strong chemical inertness of polypropylene plastic (PP) severely impedes its oxidative cleavage, making it resistant to degradation. In this study, based on sequence screening of Hidden Markov Model (HMM), a dioxygenase (HIS1) was identified and characterized to be effective in PP oxidation. Various kinds of PP products, including plastic films, microplastics, and disposable water cups or bags, were HIS1-degraded with cracks and holes on the surface. The hydrophobic binding was the primary force driving oxidative degradation in the specific cavity of HIS1. The discovery of HIS1 achieved a zero breakthrough in PP biodegradation, providing a promising candidate for the selection and evolution of degrading enzymes.

Exploring Microorganisms from Plastic-Polluted Sites: Unveiling Plastic Degradation and PHA Production Potential.

The exposure of microorganisms to conventional plastics is a relatively recent occurrence, affording limited time for evolutionary adaptation. As part of the EU-funded project BioICEP, this study delves into the plastic degradation potential of microorganisms isolated from sites with prolonged plastic pollution, such as plastic-polluted forests, biopolymer-contaminated soil, oil-contaminated soil, municipal landfill, but also a distinctive soil sample with plastic pieces buried three decades ago. Additionally, samples from Arthropoda species were investigated. In total, 150 strains were isolated and screened for the ability to use plastic-related substrates (Impranil dispersions, polyethylene terephthalate, terephthalic acid, and bis(2-hydroxyethyl) terephthalate). Twenty isolates selected based on their ability to grow on various substrates were identified as Streptomyces, Bacillus, Enterococcus, and Pseudomonas spp. Morphological features were recorded, and the 16S rRNA sequence was employed to construct a phylogenetic tree. Subsequent assessments unveiled that 5 out of the 20 strains displayed the capability to produce polyhydroxyalkanoates, utilizing pre-treated post-consumer PET samples. With Priestia sp. DG69 and Neobacillus sp. DG40 emerging as the most successful producers (4.14% and 3.34% of PHA, respectively), these strains are poised for further utilization in upcycling purposes, laying the foundation for the development of sustainable strategies for plastic waste management.

Ternary composite degradable plastics based on Alpinia galanga essential oil Pickering emulsion templates: A potential multifunctional active packaging

To reduce the use of petroleum-based plastics and explore multifunctional plastics, this study was conducted to prepare ternary composite plastics by doping Pickering emulsions containing Alpinia galanga essential oil into a polymer network consisting of poly(vinyl alcohol)-acetylated pullulan polysaccharides. Scanning electron microscopy results showed that although incompatible components were present in the composite plastic, compatibility improved with the addition of pullulan polysaccharides, resulting in smooth surfaces and cross-sections, which was consistent with the observation of continuous dark zones and low relative roughness (Ra = 5.51) in Atomic force microscopy. Further, Fourier transform spectroscopy and X-ray diffraction characterization revealed that the composite plastic disrupted the molecular and crystalline structures of the pure PVA, causing the stretching vibration of -OH and the decrease of relative crystallinity. Moreover, this plastic performed optimally at a PVA to pullulan polysaccharide ratio of 75:25, exhibiting good thermal (13.12 J/g) and mechanical properties, low water absorption (70.71 %) and water vapor transmission (1.80 × 10−3 g/m2 s), as well as excellent degradability. In addition, Alpinia galanga essential oil components in the composite plastic provided favorable antioxidant scavenging of DPPH and ABTS and inhibitory effects against Escherichia coli and Staphylococcus aureus. Chicken meat packaging revealed that the plastic maintained sensory parameters such as pH and color by inhibiting the oxidation of proteins and lipids during shelf-life. The findings provide insights into developing innovative, green, multifunctional packaging and broaden the in-depth application of Alpinia galanga essential oil.

Effects of environmentally relevant concentrations of micro(nano)plastics on aquatic microorganisms: Changes in potential function but not in overall composition

Micro(nano)plastics (MNPs) are a growing problem as persistent environmental pollutants. Here, we investigated the impact of MNPs on microorganisms in aquatic microbial floc exposed to NPs (80 ​nm) and MPs (8 ​μm) for 35 days. Water quality indicators were tested weekly and microbiological analyses were conducted on Day 7 and 28 after exposure. The results showed that there were significant differences in the levels of total ammonia nitrogen or nitrite between the MNPs groups and the control group, spanning from Day 7 to Day 28. For the microbial response, microbial community richness in the NPs and MPs groups were significantly increased at Day 7. Functional prediction showed that the relative abundances of bacteria associated with the “Forms Biofilms”, “Potentially Pathogenic”, “Plastic Degradation” and nitrogen cycle processes were significantly different after MNPs exposure. The results suggest that MNPs had no significant effect on the microbial diversity of mature microbial flocs. Findings suggest MPs could cause an increase in the relative abundance of potentially pathogenic bacteria, while NPs do not. In addition, stress associated with MNPs affected the nitrogen cycle of microorganisms, and NPs exerted greater impacts than MPs. Findings from this study further our understanding of the impact of MNPs at environmentally relevant concentrations on microorganisms in aquatic ecosystems.

Microplastic Contaminant in Indonesia: A review on Debris, Exposure, Health Risk and Future Perspective

Microplastics are growing environmental concern, posing risks to both ecosystem and human health, especially in marine environments. Purpose this review is studied debris, exposure, health risk and future perspective of microplastic contaminant in Indonesia. This review method is collects the studied from google scholar, with publisher: ScienceDirect, Elsevier, Springer, Frontiers, MDPI, IOP Conference, Nature, Taylor & Francis. Keyword was used microplastic, debris, environmental exposure, health risk, Indonesia. Result finds the kind of microplastic debris are Fragment, Fiber, Granule, Film, Foam and Filament. Microplastic exposure the water organism including fish, shellfish, seabirds, table salt, snail and crab. It has an impact on human health when people consume seafood that contains microplastics through the food chain. Human exposure to microplastics occurs through various routes, including ingestion of contaminated food and water, inhalation of airborne particles, and dermal contact. Health risk indicate that microplastics can accumulate in the gastrointestinal tract, potentially leading to inflammation, disruption of gut microbiota, and even the release of hazardous chemicals. The future perspective is needed continued research, monitoring, and policy measures are necessary to effectively mitigate microplastic pollution in Indonesia and safeguard its ecosystems and public health. Overalls, it needs solid waste management and use degradable plastics.

Short-term fragmentation of single-use plastic carrier bags in natural environment

About 50% of single-use plastic carrier bags are discarded after one use. There has been a gradual increase in awareness of the accumulation of end-of-life plastics and their impact on the environment, which has led to interest in the development of degradable polymers. Cassava bioplastics (polylactic acid), oxo-biodegradable, and compostable plastics are often considered a potential solution to the accumulation of plastic waste, but it was unknown whether they can be biodegraded in the natural environment. Thus, this study aims to determine the fragmentation of single-use plastic bags under various natural conditions, which are declared to have biodegradable, oxo-biodegradable, or compostable properties. Four types of degradable plastic and conventional single-use plastic carrier bags were stored in natural conditions (open-air, river water, and soil). After one month, we conducted an analysis of plastic bags, specifically examining factors such as their visual attributes, load-bearing capacity, polymer identification, and microplastic generation. Surprisingly, the compostable plastic, which was expected to demonstrate enhanced degradation when buried in soil, remained stable, as indicated by its polymer composition. This finding suggests that there is a need to improve the criteria for biodegradable plastic carrier bags to ensure that they undergo biological degradation.

Mirror assembly of spherical chitosan-based additives: Towards a circular revolution of PLA from high-value applications to soil degradation

Polylactic acid (PLA) is recognized as a promising alternative to traditional petroleum-based plastics due to its excellent biodegradability and well-balanced mechanical properties. Nevertheless, the disadvantages of PLA such as flammability in fire, susceptibility to UV light attack, and slow natural degradation rate limit its application and recovery in high-security areas. In this work, a spherical chitosan-based additive DMPC-Al with mirror-symmetric internal structure was assembled by layer-by-layer electrostatic reactions, resulting in PLA characterized excellent comprehensive performances. When 7 wt% DMPC-Al was added into PLA, the LOI value of the composite PLA/7DMPC-Al was increased to 29.6%, and UL-94 reached V-0 grade without any molten droplets. The peak heat release rate and total heat release rate were reduced by 13.5% and 16.2%, respectively, and the carbon layer was highly self-expanding. In addition, the UPF of PLA/7DMPC-Al was increased to 34.45 from 0.45 of pure PLA, blocking most of the UV light attacks and extending the service life of PLA. Surprisingly, DMPC-Al actually improved the impact toughness of PLA by 38.5% and facilitated PLA to work continuously when drawing large curved shapes by 3D printing. More importantly, the introduction of DMPC-Al changed the sensitivity of PLA to water and provided sufficient energy for microbial growth, thus accelerating the degradation rate of PLA in the soil under abandoned buildings. This work provides a practical and feasible strategy to achieve multifunctionality of degradable plastics.

Sustainable production and degradation of plastics using microbes.

Plastics are indispensable in everyday life and industry, but the environmental impact of plastic waste on ecosystems and human health is a huge concern. Microbial biotechnology offers sustainable routes to plastic production and waste management. Bacteria and fungi can produce plastics, as well as their constituent monomers, from renewable biomass, such as crops, agricultural residues, wood and organic waste. Bacteria and fungi can also degrade plastics. We review state-of-the-art microbial technologies for sustainable production and degradation of bio-based plastics and highlight the potential contributions of microorganisms to a circular economy for plastics.

Removal of polyethylene terephthalate plastics waste via Co–CeO2 photocatalyst–activated peroxymonosulfate strategy

Polyethylene terephthalate (PET) plastic, widely used for packaging owing to its excellent properties, has become a major contributor to plastic waste, for which satisfactory recycling and upgrading treatment technologies are lacking. In this study, Co-doped CeO2 was used as a photocatalyst to degrade PET plastics in water, and PET degradation was measured according to the weight loss rate. Peroxymonosulfate (PMS) addition to the photocatalytic system enabled the degradation of 53.82 ± 4.48 % of PET plastics, highlighting the excellent PET plastic degradation capability of the photocatalytic PMS system. The study investigated the effects of the catalyst-to-plastic ratio, PMS concentration, initial pH, inorganic anions, humic acid concentration, and hydrogen peroxide (H2O2) addition on the catalytic oxidation system. Contrast experiments revealed that H2O2 addition to the photocatalysis/PMS oxidation system further improved the PET plastic degradation efficiency (91.61 ± 1.50 %). Liquid product analysis, electron paramagnetic resonance, and free radical quenching experiments confirmed that SO4− played the most significant role in PET degradation. Finally, a possible mechanism for the degradation of PET plastics in water using the photocatalysis/PMS oxidation system was proposed.

Research Status and Perspectives of Plastic Degradation

Contemporary society has witnessed a large variety of hazard plastic made. Plastic waste has become a major concern for individuals, governments, and organizations all over the world. The extensive use of plastics in producing consumer goods has resulted in huge amounts of plastic waste that has to be managed appropriately. Plastic waste is hazardous to the environment because it takes a long time to decompose. This article starts with a range of explanation techniques and outlines their principles and origins, for examples of common practices in today's culture include photocatalytic degradation, thermal degradation, biodegradation, etc. In the hope that they might effectively decompose these toxic compounds, many people are now pursuing study in these areas in order to offer a quick analysis of the current major explanation methods. A rise in future deteriorating methods can alleviate the negative effects on both human and animals’ life, and thus a healthier ecological environment can be achieved.

Enhancing the volatile fatty acids production from food waste as well as polylactate plastic degradation by coupled with hydrothermal pretreatment

Aspolylactate plastic (PLA)degradationis unsatisfactory in the mesophilic anaerobic fermentation process,this work aimed to unveil the influence of PLA on the characteristics of food waste acidogenic fermentation and enhance the volatile fatty acids (VFAs) production as well as PLA degradation by hydrothermal treatment. The addition of PLA slightly increased the VFAs yield by 6.05 %, while its mass loss rate was only 1.09 % after 12 d fermentation. Hydrothermal treatment could effectively promote the PLA degradation and the dissolution of organic matter in PLA-containing food waste, and 160 °C as well as 40 and 60 min were the ideal hydrothermal conditions with high PLA degradation rate (more than 86 %) and soluble organic materials. In addition, VFAs production from PLA-containing food waste was significantly enhanced by hydrothermal treatment. The maximum yield was obtained under the condition of 160 °C and 60 min, which was 110.06 % higher than the blank group. Moreover, the fermentation time was shortened from 10 d to 4 d.

Excavating the Potential of Photo‐ and Electroupcycling Platforms Toward a Sustainable Future for Waste Plastics

Traditionally, waste plastics have been recycled using crude recycling processes, which pose serious environmental pollution and low recycling efficiency. The best option for managing waste plastics is to upgrade them into high‐value‐added chemicals by breaking down specific chemical bonds in plastic polymers. Herein, this article reviews recent representative research advancements in photo‐ and electrodegradation of plastics for obtaining small‐molecule, high‐value‐added chemicals. The focus is on the application and analysis of emerging technological processes and catalytic materials concepts in these upcycling pathways, with particular emphasis on the diverse functions exhibited by various catalysts. Through the optimization of plastic degradation processes with the rational design of degradation technical processes and catalysts, efficient and selective access to the target products, with the assistance of light and electrical energy with similar action principles, can be achieved. These efforts have yielded promising results, paving the way for resourceful plastic recycling. Particularly, the challenges that arise in upcycling of waste plastics are seriously discussed, and reasonable recommendations have been made to understand future developments and prospects in this research area. It is believed that photocatalysis and electrocatalysis, two emerging degradation methods, play an increasingly important role in the field of plastic upcycling.

Establishment of plastic-associated microbial community from superworm gut microbiome

Gut microbial communities of plastic-munching worms provide novel insights for the development of plastic-processing biotechnologies. Considering the complexity of worm maintenance and the gut microbial communities, it is challenging to apply the worms directly in plastic processing. Harnessing the power of microbial communities derived from the worm gut microbiomes in vitro may enable a promising bioprocess for plastic degradation. Here, we established stable and reproducible plastic-associated biofilm communities derived from the gut microbiome of a superworm, Zophobas atratus, through a two-stage enrichment process: feeding with plastics (HDPE, PP, and PS) and in vitro incubation of gut microbiomes obtained from the plastic-fed worms. Plastic feeding exhibited marginal influence on bacterial diversity but substantially changed the relative abundance of different bacterial groups, and intriguingly, enriched potential plastic degraders. More prominent shifts of microbial communities were observed during the in vitro incubation of the gut microbiomes. Taxa containing plastic-degrading strains were further enriched, while other taxa represented by lactic acid bacteria were depleted. Additionally, the plastic characterization confirmed the degradation of the incubated plastics by the plastic-associated microbial communities. Community functional inference for both gene abundance and community phenotype suggested that the in vitro incubation enhanced plastic-degrading potential. Deterministic ecological effects, in particular, selection processes, were identified as the main driving force of the observed community shifts. Our findings provide novel insights into plastic-munching-worm-inspired bioprocessing of plastic wastes.

Solid- and aqueous-phase approaches on zinc oxide-based photocatalytic system for degradation of plastics and microplastics: A review

The accumulation of plastics and microplastics in the environment is a major global concern because of their negative impact on ecosystems and human health. The use of zinc oxide (ZnO)-based systems for photocatalytic degradation of these pollutants has shown promise. This review presents an overview of the solid- and aqueous-phase approaches employed for the degradation of plastics and microplastics using ZnO-based photocatalytic systems. The preparation of microplastic samples is discussed, highlighting various techniques used to generate representative samples for testing. The experimental setup or reactor design is explored, encompassing different configurations employed in both the solid- and aqueous-phases. Next, the impact of reaction conditions on degradation efficiency is investigated, including catalyst concentration, pH, temperature, and irradiation source. Sampling techniques for post-reaction analysis are explored, discussing methods for collecting and analyzing degraded products and byproducts in solid- and aqueous-phases. The comparative discussion was meant to assess the effectiveness and suitability of solid- and aqueous-phase methods, revealing their potential for practical use. This review paper presents an extensive analysis of the methods used in ZnO-based photocatalytic systems for plastic and microplastics degradation which the output will aid researchers and practitioners in developing effective strategies to mitigate plastic pollution.

Plastic waste to sustainable solutions: accelerating the biodegradation of syn-thetic plastics

Plastic waste to sustainable solutions: accelerating the biodegradation of syn-thetic plastics BioICEP combines chemical and biological methods to turn fossil-based plastic waste into natural, biodegradable substitutes for the packaging and pharma industries. It combines three technologies that enhance, accelerate and increase the degradation of plastics to levels far beyond what is currently possible. A triple-action depolymerization system breaks down plastic waste through chemical disintegration processes, biocatalytic digestion and microbial consortia.

UV Irradiation of Polyethylene Terephthalate and Polypropylene and Detection of Formed Microplastic Particles Down to 1 μm.

The degradation of plastics upon UVC irradiation in aqueous solution and the formation of microplastic (MP) particles were investigated. Polypropylene (PP) and recycled and virgin polyethylene terephthalate (PET) were irradiated with a UV lamp emitting light at 254 nm. Irradiation was performed for 15 and 30 min, respectively, at an intensity of about 0.3 W cm-2 . The formation of MP was studied by Raman spectroscopy. The results showed that MP particles were formed after irradiation and that their number was significantly higher in the recycled PET than in the virgin material. The number of PP MP formed was lower compared to PET and was not significantly different after 15 and 30 min. In addition, ethanol was used as an alternative solvent to investigate how its chemical properties and interactions with UVC irradiation affect the degradation of PET and PP plastics. The use of ethanol and recycled PET resulted in a lower number of MP particles at both irradiation times. When ethanol was used after 30 min of irradiation, significantly more PP MP formed. The different chemical structures of PET and PP combined with the different solvent properties of water and ethanol contribute to the differences in their susceptibility to UVC degradation.

Isolation, Characterisation and Evaluation of Plastic Degrading Properties of Soil Biofilms Collected from Chennai District

Environmental pollution due to accumulation of synthetic polymers namely plastics is a growing concern which threatens the terrestrial marine flora and fauna. Traditional methods of plastic disposal include incineration and disposal into landfills or water bodies. Incineration of polyethylene, polystyrene leads to emission of a large amount of carbon monoxide which is toxic if inhaled and also a potent greenhouse gas. Degradation of plastic by microorganisms is an efficient and eco-friendly method employed for rapid rate of disintegration. The biofilm present in the contaminated soil survives by adapting to harsh environment by secreting hydrolysing enzymes which are potent in degradation of the accumulated plastics. The present study deals with the isolation, characterisation and evaluation of plastic degrading properties of microorganisms isolated from various soil samples collected from Chennai district. Soil samples were collected aseptically from various locations & isolated by standard plate count method. The isolated organisms were identified by staining methods and characterized by phylogenetic analysis. The organism Pseudomonas aeruginosa and Streptomyces fulvissimus were further subjected to plastic degradation testing. The present study demonstrates the ability of Pseudomonas aeruginosa and Streptomyces fulvissimus to degrade polyethylene sheets.

Toxic effects on ciliates under nano-/micro-plastics coexist with silver nanoparticles

Owing to the degradation of plastics, microplastics (MPs) and nanoplastics (NPs) have remained the focus of global attention. Silver nanoparticles (AgNPs) could adversely affect marine organisms due to their broad application. So far, the combined effects of MPs/NPs (strong adsorbents) with AgNPs on marine organisms are scant. Thus, four sizes polystyrene beads (80 nm, 220 nm, 1.07 µm, and 2.14 µm) combined with AgNPs (30 nm) were assessed using ciliated protozoa Uronema marinum. Results showed that MPs/NPs dramatically decrease the abundance, biovolume, and carbon biomass of U. marinum. And, exposure could cause changes of antioxidant enzyme activity and antioxidant content on U. marinum. The combined toxicity of MPs/NPs with AgNPs to ciliates showed an enhanced effect compared to exposure alone. Additionally, the negative effects under exposure of NPs plus AgNPs were more significant than those of MPs plus AgNPs. Transcriptome sequencing showed that co-exposure could affect the energy metabolism and lipid metabolism of ciliates, even cause DNA and protein damage. Our study provided a novel insight and first-hand basic data for the understanding of combined toxicity of MPs /NPs with AgNPs on the basic trophic level ciliated protozoa in marine ecosystems.

Beyond Microbial Biodegradation: Plastic Degradation by Galleria mellonella

One of the major environmental issues that modern civilizations are currently dealing with is the growing amount of plastic waste. Because of how they affect all forms of life, this waste is seen as a severe worldwide issue. Current methods for plastic waste disposal do not offer definitive solutions and often lead to the production of microplastics or secondary pollution. In recent years there has been a growing interest by the scientific community in the degradation of plastics by biological means, in particular the possibilities of using insects as a potential solution to the accumulation of this type of waste have been investigated. Among these, one of the most promising is undoubtedly the lepidopteran Galleria mellonella, which synthesizes the first ever discovered polyethylene degrading enzymes. In this review we propose an overview of plastic polymers production and common degradation methodologies, and analyses the current state of the art about the degradation carried out by this insect.

Characterization of the dynamic aging and leached dissolved organic carbon from biodegradable and conventional plastics under photooxidation

Biodegradable plastics have been regarded as promising candidates in the struggle against plastic pollution. However, the aging and dynamic leaching process of biodegradable and conventional plastics under photooxidation is still unclear. Herein, three types of non-biodegradable plastics (polypropylene, polyethylene, and polyethylene terephthalate), and two types of biodegradable plastics (polylactic acid and cornstarch-based plastics) were treated with 21 days of photooxidation followed by 13 days of dark conditions. Scanning electron microscopy was applied to display the morphological changes. Also, the carbonyl index, oxygen-to-carbon ratio, and contact angle were utilized to characterize the aging degree of the plastic surface. Unexpectedly, biodegradable plastics did not always display a greater aging degree than non-biodegradable plastics. Moreover, the dissolved organic carbon during the leaching process was identified using excitation-emission matrix fluorescence spectroscopy. The findings suggested that biodegradable plastics showed the potential to release more dissolved organic carbon. Particularly, the polylactic acid plastic displayed higher concentrations and more types of dissolved organic carbon release than that of conventional plastics in our experiment. This research highlights the necessity for monitoring the aging process of both biodegradable and non-biodegradable plastics and the non-negligible ecological risk of leached organic pollutants due to plastic degradation.