Microplastic pollution: Understanding microbial degradation and strategies for pollutant reduction

Exposure of the human placental primary cells to nanoplastics induces cytotoxic effects, an inflammatory response and endocrine disruption

Humans are inevitably exposed to micro- and nanoplastics (MP/NP). These particles are able to cross the biological barriers and enter the bloodstream with levels close to 1.6 µg mL-1; MP/NP have been detected in placentas and meconium of newborns. However, the consequences of this exposure on the integrity, development and functions of the human placenta are not documented. In this study, trophoblasts purified from human placentas at term were exposed for 48 h, to two different sizes of polystyrene nanoparticles (PS-NP) of 20 nm (PS-NP20) and 100 nm (PS-NP100), at environmental and supra-environmental concentrations (0.01-100 µg mL-1). Cell viability, oxidative stress, mitochondrial dynamics, lysosomal degradation processes, autophagy, inflammation/oxidative responses and consequences for placental endocrine and angiogenic functions were assessed. PS-NP size determines their internalization rate and their behavior in trophoblasts. Indeed, PS-NP20 are more rapidly translocated, and accumulated in lysosomes as shown by confocal and TEM imaging. They induce higher cytotoxicity than PS-NP100, as early as 1 µg mL-1 (p < 0.05). In addition, they induce a pro-inflammatory cytokines response: IL-1ß is induced from 0.01 µg mL-1 for the both nanoparticle sizes; IL-6, and TNF-α are overexpressed at 100 µg mL-1 only for PS-NP20 (p < 0.05). For the first time, we report that PS-NP disrupt endocrine function, as observed by a decreased hCG release at concentrations found in human blood. This work, provides an in-depth in vitro assessment of the effects of PS-NP on the human placenta.

Biodegradation of polyethylene with polyethylene-group-degrading enzyme delivered by the engineered Bacillus velezensis

Microplastics (MPs) pose an emerging threat to vegetable growing soils in Harbin, which have a relatively high abundance (11,065 n/kg) with 17.26 of potential ecological risk of single polymer hazard (EI) and 33.92 of potential ecological risk index (PERI). Polyethylene (PE) is the main type of microplastic pollution in vegetable growing soils in Harbin. In this study, the engineered Bacillus velezensis with polyethylene-group-degrading enzyme pathway (BCAv-PEase) was constructed to enhance the degradation of MPs of PE (PE-MPs). BCAv-PEase increased the biodegradation of PE-MPs, promoted weight loss of PE films, elevated surface tension, and decreased the surface hydrophobicity of PE through upregulating activities of depolymerases, dehydrogenase, and catalase. Mechanism analysis showed that BCAv-PEase degraded PE-MPs by promoting the secretion of PEase, thereby leading to the generation of new oxygenated functional groups within the PE-MPs substrate, which further accelerated the metabolic pathway of PE-MPs. The analysis of the microbial community during the PE-MPs degradation processes revealed that BCAv-PEase emerged as the principal bacterial player and stimulated the abundance of microbes and functional genes associated with the biodegradation of PE. In conclusion, this study provides a potential mechanism for biodegradation of PE-MPs mediated by BCAv-PEase via modulating substrate selectivity and optimizing biocatalytic pathways.

Quantifying synthetic bacterial community composition with flow cytometry: efficacy in mock communities and challenges in co-cultures

Determination of bacterial community composition in synthetic communities is critical for understanding microbial systems. The community composition is typically determined through bacterial plating or through PCR-based methods, which can be labor-intensive, expensive, or prone to bias. Simultaneously, flow cytometry has been suggested as a cheap and fast alternative. However, since the technique captures the phenotypic state of bacterial cells, accurate determination of community composition could be affected when bacteria are co-cultured. We investigated the performance of flow cytometry for quantifying oral synthetic communities and compared it to the performance of strain specific qPCR and 16S rRNA gene amplicon sequencing. Therefore, axenic cultures, mock communities and co-cultures of oral bacteria were prepared. Random forest classifiers trained on flow cytometry data of axenic cultures were used to determine the composition of the synthetic communities, as well as strain specific qPCR and 16S rRNA gene amplicon sequencing. Flow cytometry was shown to have a lower average root mean squared error and outperformed the PCR-based methods in even mock communities (flow cytometry: 0.11 ± 0.04; qPCR: 0.26 ± 0.09; amplicon sequencing: 0.15 ± 0.01). When bacteria were co-cultured, neither flow cytometry, strain-specific qPCR, nor 16S rRNA gene amplicon sequencing resulted in similar community composition. Performance of flow cytometry was decreased compared with mock communities due to changing phenotypes. Finally, discrepancies between flow cytometry and strain-specific qPCR were found. These findings highlight the challenges ahead for quantifying community composition in co-cultures by flow cytometry.IMPORTANCEQuantification of bacterial composition in synthetic communities is crucial for understanding and steering microbial interactions. Traditional approaches like plating, strain-specific qPCR, and amplicon sequencing are often labor-intensive and expensive and limit high-throughput experiments. Recently, flow cytometry has been suggested as a swift and cheap alternative for quantifying communities and has been successfully demonstrated on simple bacterial mock communities. However, since flow cytometry measures the phenotypic state of cells, measurements can be affected by differing phenotypes. Especially, changing phenotypes resulting from co-culturing bacteria can have a profound effect on the applicability of the technique in this context. This research illustrates the feasibility and challenges of flow cytometry for the determination of community structure in synthetic mock communities and co-cultures.

Aging of plastics and microplastics in the environment: a review on influencing factors, quantification methods, challenges, and future perspectives

The ubiquitous presence of fragmented plastic particles needs comprehensive understanding of its fate in the environment. The long-term persistence of microplastics (MPs) in the environment is a significant threat to the ecosystem. Even though various degradation mechanisms (physical, chemical, and biological) of commonly used plastics have been demonstrated, quantifying the degradation of MPs over time to predict the consequence of plastic littering and its persistence in the environment remains a challenge. Different advanced analytical techniques have been used to quantify the degradation of MPs by introducing various parameters such as bond indices, crystallinity, and carbon-oxygen ratio. However, a simple and widely accepted reliable methodology for comparing the environmental factors and their influence on the MP degradation has yet to be developed and validated. This paper reviews a section of relevant literature (n = 38) to synthesize an overview of methods implemented for the quantification of fragmentation and aging of MPs in natural and artificial environment. In addition, the inherent weakness and extrinsic factors affecting the degradation of MPs in the environment is discussed. Finally, it proposes challenges and future scope as guideline for research on MP degradation in the environment.

Atmospheric microplastic input into wetlands: Spatiotemporal patterns, drivers, and unique ecological impacts

Wetlands are major microplastic sinks with a large atmospheric input. However, many details of such deposited atmospheric microplastics entering into wetlands remain unclear, including temporal patterns of input and ecological effects. We monitored the aerial microplastics during four seasons in eleven economically developed cities along the lower reaches of the Yangtze River Basin, China. The average microplastic deposition rate was 512.31 items m-2 d-1, equivalent to an annual contribution of 17.46 metric tons of plastic to the surveyed wetlands with a total area of 1652 km2. These microplastics were predominantly composed of polyamide and polyethylene terephthalate with 61.85 ± 92.29 µm sized pellets, and we obtained similar results for microplastics intercepted on moss in wetlands. Microplastic input varied between wet and dry periods, primarily influenced by wind, rainfall and ozone concentration. Civilian vehicle density and textile industry were the primary socioeconomic factors driving microplastic deposition. Further indoor microcosm experiments revealed that moss phyllosphere bacterial community structure and function were influenced by microplastic abundance and size, exemplifying the unique ecological risks of aerially deposited microplastics to wetlands. These results indicate that mosses and their phyllosphere microbiota could serve as bio-indicators of aerial microplastic characteristics and impacts.

Comparative life cycle assessment of PBAT from fossil-based and second-generation generation bio-based feedstocks

With the increasing demand for plastics, plastic pollution is growing rapidly. A significant amount of plastic has leaked into the environment, leading to severe environmental issues. Biodegradable plastics are considered promising alternatives to conventional durable plastics, and the environmental impacts of biodegradable plastics have received increasing attention. Poly (butylene adipate-co-terephthalate) (PBAT) is a commercial and cost-competitive biodegradable polymer and has been applied in the packaging and agriculture sectors. The environmental performances of PBAT with second-generation feedstocks from forestry waste have been rarely investigated. Since China is the leading global producer and exporter of PBAT polymer, Chinese cradle-to-gate life cycle inventories of PBAT were compiled in this study. A comparative life cycle assessment (LCA) was conducted to explore the potential for environmental performance of PBAT with second-generation bio-based feedstock compared to fossil-based PBAT and conventional plastics. The results showed that feedstocks contributed to more than 70 % of 18 environmental impact categories of fossil-based PBAT. In comparison, PBAT with second-generation bio-based feedstock reduces the environmental loads in 16 impact categories by 15-85 %, and renewable energy substitution has the potential to reduce environmental impacts by 10 %. Bio-based PBAT performs better than PVC, PP, HDPE, LDPE, and PET in 16 impact categories by 15-80 %. Bio-based PBAT has GWP of 3.72 kg CO2 eq, which is 37 % lower than fossil-based PBAT (5.89 kg CO2 eq) and 18-32 % lower than conventional plastics. Since feedstock dominates the environmental performance of PBAT, the development of biomanufacturing technologies for bio-based polymers and chemicals could significantly improve environmental performance of biodegradable plastics and promote the sustainable development of the plastic industry. Results could serve as the basis for environmental impact and mitigation strategies for biodegradable plastics with bio-based feedstocks, as well as the sustainable development of the PBAT industry.

Development and characterization of cornstarch-based bioplastics: Influence of fructose concentration and titanium dioxide (TiO2) variations on structural, chemical bonding, and nutrient-related properties of mung bean plants

This study investigates an environmentally friendly bioplastic made from cornstarch with fructose and different amounts of titanium dioxide (TiO2). The research focuses on its physical, chemical bonding, and nutritional properties. X-ray diffraction analysis indicates that TiO2 influences diffraction peaks, affecting the crystal size, with the smallest size of 12.54 nm observed in Sample (II) containing 0.1 g of TiO2. Fourier transform infrared analysis shows slight shifts in the stretching of the -OH groups, indicating consistent elemental composition. The mechanical properties of the bioplastic for Sample (I) lacking TiO2 exhibits the highest Young's modulus of 1.02593 MPa and a tensile strength of 0.1345 MPa. In terms of biodegradation, the cornstarch-based bioplastic decomposes by approximately 80 % in soil after 28 days, aided by moisture and soil microorganisms. Water resistance analysis of the cornstarch-based bioplastic indicates that the sample containing 0.1 g of TiO2 exhibits the highest percentage, with 66.66 % absorption after 120 s. Nutrient concentration analysis using mung bean plants shows increased levels of calcium, potassium, and iron in samples with TiO2, particularly in Sample (II) containing 0.1 g of TiO2, which has significantly higher nutrient content, namely 2.15 % calcium, 1.99 % potassium, and 424.46 ppm iron.

Direct evidence for selective microbial enrichment with plastic degradation potential in the plastisphere

Plastisphere, characterized by microbial colonization on plastic debris, has attracted concern with its adverse environmental effects. The microbial features have been increasingly investigated; however, there lacks direct evidence for microplastics serving as carbon sources and enriching plastic-degrading microorganisms. Here, we obtained microbial communities from soil microplastics, analyzed the dissimilarity compared with soil, and characterized the plastic-degrading potential of isolates from plastisphere. Results showed the plastisphere communities significantly differed from soil communities and exhibited a higher relative abundance of Nocardia and Rhodococcus. To verify the selective enrichment of plastic-degrading microorganisms in the plastisphere, culture-based strategies were employed to evaluate the polyethylene (PE) degradation potential of two isolates Nocardia asteroides No.11 and Rhodococcus hoagii No.17. They could grow solely on PE and led to significant weight loss. FTIR and SEM analysis revealed the formation of new functional groups and the destruction of structural integrity on PE surfaces. Genes related to PE biodegradation were identified by genome-wide sequencing thus recognizing relevant enzymes and elucidating potential pathways. Overall, this report combined culture-free and culture-based approaches to confirm the plastic degradation potential of selectively enriched microorganisms in soil plastisphere, providing a positive perspective toward promoting microplastic biodegradation in farmland soil by enhancing natural microbial processes.

Distribution, characteristics, and ecological risks of microplastics in the Hongyingzi sorghum production base in China

Microplastics (MPs), an emerging pollutant of global concern, have been studied in the Hongyingzi sorghum production base. In this study, we investigated MPs in the surface soil (0-10 cm) and deeper soil (10-20 cm) in the Hongyingzi sorghum production base. Pollution characterization and ecological risk evaluation were conducted. The results revealed that the MP abundance ranged from 1.31 × 102 to 4.27 × 103 particles/kg, with an average of 1.42 ± 1.22 × 103 particles/kg. There was no clear correlation between the MP abundance and soil depth, and the ordinary kriging method predicted a range of 1.26 × 103-1.28 × 103 particles/kg in most of the study area, indicating a relatively uniform distribution. Among the 12 types of MPs detected, acrylates copolymer (ACR), polypropylene (PP), polyurethane (PU), and polymethyl methacrylate (PMMA) were the most frequently detected. These MPs primarily originated from packaging and advertising materials made from polyurethane and polyester used by Sauce Wine enterprises, as well as plastic products made from polyolefin used in daily life and agricultural activities. The particle size of MPs was primarily 20-100 μm. Overall, the proportion of the 20-100 μm MP was 95.1% in the surface soil layer and 86.7% in the deeper soil layer. Based on the pollution load index, the MP pollution level in the study area was classified as class I. Polymer hazard index evaluation revealed that the risk levels at all of the sampling sites ranged from IV to V, and ACR, PU, and PMMA were identified as significant sources of polymer hazard. Potential ecological index evaluation revealed that most of the soil samples collected from the study area were dangerous or extremely dangerous, and the surface soil posed a greater ecological risk than the deeper soil. These findings provide a scientific foundation for the prevention, control, and management of MP pollution in the Hongyingzi sorghum production base.

Impacts of microplastics on ecosystem services and their microbial degradation: a systematic review of the recent state of the art and future prospects

Microplastics are tiny plastic particles with a usual diameter ranging from ~ 1 μ to 5 µm. Recently, microplastic pollution has raised the attention of the worldwide environmental and human concerns. In human beings, digestive system illness, respiratory system disorders, sleep disturbances, obesity, diabetes, and even cancer have been reported after microplastic exposure either through food, air, or skin. Similarly, microplastics are also having negative impacts on the plant health, soil microorganisms, aquatic lives, and other animals. Policies and initiatives have already been in the pipeline to address this problem to deal with microplastic pollution. However, many obstacles are also being observed such as lack of knowledge, lack of research, and also absence of regulatory frameworks. This article has covered the distribution of microplastics in water, soil, food and air. Application of multimodel strategies including fewer plastic item consumption, developing low-cost novel technologies using microorganisms, biofilm, and genetic modified microorganisms has been used to reduce microplastics from the environment. Researchers, academician, policy-makers, and environmentalists should work jointly to cope up with microplastic contamination and their effect on the ecosystem as a whole which can be reduced in the coming years and also to make earth clean.

Host-associated microbes mitigate the negative impacts of aquatic pollution

Pollution can negatively impact aquatic ecosystems, aquaculture operations, and recreational water quality. Many aquatic microbes can sequester or degrade pollutants and have been utilized for bioremediation. While planktonic and benthic microbes are well-studied, host-associated microbes likely play an important role in mitigating the negative impacts of aquatic pollution and represent an unrealized source of microbial potential. For example, aquatic organisms that thrive in highly polluted environments or concentrate pollutants may have microbiomes adapted to these selective pressures. Understanding microbe-pollutant interactions in sensitive and valuable species could help protect human well-being and improve ecosystem resilience. Investigating these interactions using appropriate experimental systems and overcoming methodological challenges will present novel opportunities to protect and improve aquatic systems. In this perspective, we review examples of how microbes could mitigate negative impacts of aquatic pollution, outline target study systems, discuss challenges of advancing this field, and outline implications in the face of global changes.

The role of gut microbiota in MP/NP-induced toxicity

Microplastics (MPs) and nanoplastics (NPs) are globally recognized as emerging environmental pollutants in various environmental media, posing potential threats to ecosystems and human health. MPs/NPs are unavoidably ingested by humans, mainly through contaminated food and drinks, impairing the gastrointestinal ecology and seriously impacting the human body. The specific role of gut microbiota in the gastrointestinal tract upon MP/NP exposure remains unknown. Given the importance of gut microbiota in metabolism, immunity, and homeostasis, this review aims to enhance our current understanding of the role of gut microbiota in MP/NP-induced toxicity. First, it discusses human exposure to MPs/NPs through the diet and MP/NP-induced adverse effects on the respiratory, digestive, neural, urinary, reproductive, and immune systems. Second, it elucidates the complex interactions between the gut microbiota and MPs/NPs. MPs/NPs can disrupt gut microbiota homeostasis, while the gut microbiota can degrade MPs/NPs. Third, it reveals the role of the gut microbiota in MP/NP-mediated systematic toxicity. MPs/NPs cause direct intestinal toxicity and indirect toxicity in other organs via regulating the gut-brain, gut-liver, and gut-lung axes. Finally, novel approaches such as dietary interventions, prebiotics, probiotics, polyphenols, engineered bacteria, microalgae, and micro/nanorobots are recommended to reduce MP/NP toxicity in humans. Overall, this review provides a theoretical basis for targeting the gut microbiota to study MP/NP toxicity and develop novel strategies for its mitigation.

Graphing the Green route: Enzymatic hydrolysis in sustainable decomposition

This graphical review article explores how sustainable decomposition contributes to environmental sustainability in waste management with a focus on enzymatic hydrolysis. Methods such as composting and anaerobic digestion efficiently break down organic waste and reduce landfill use and greenhouse gas emissions, while producing valuable resources such as compost and biogas. In particular, enzymatic hydrolysis offers advantages over chemical methods because it operates under mild conditions, targets specific substrates precisely, and yields purer products with fewer side reactions. Its renewable and biodegradable nature aligns with sustainability goals, making it suitable for waste decomposition, biorefining, and resource recovery. Enzymatic waste conversion reduces waste and pollution, conserves natural resources, and supports circular economy. Various ongoing studies have aimed to enhance the efficiency and environmental benefits of enzymatic hydrolysis, enabling innovative waste-to-value solutions that address environmental, economic, and social challenges. This article emphasizes the importance of its timely examination of enzymatic hydrolysis as a prominent method for sustainable waste decomposition, stressing its environmental, economic, and societal benefits. It distinguishes itself through its extensive analysis of chemical methods, its emphasis on the circular economy, and its delineation of future research directions and the need for interdisciplinary collaboration to advance this innovative technology.

Microbial Allies in Plastic Degradation: Specific bacterial genera as universal plastic-degraders in various environments

Microbiological degradation of polymers offers a promising approach for mitigating environmental plastic pollution. This study (i) elucidated the diversity and structure of bacterial microbiomes from distinct environments (landfill soil, sewage sludge, and river water) characterized by specific physicochemical parameters, and (ii) utilized environment-derived microbial cultures enriched with microplastics (MPs) to investigate the degradation of polymers and identify culturable bacterial strains contributing to the plastisphere. We found that alpha diversity was notably higher in river water (∼20%) compared to landfill soil and sewage sludge. Dominant phyla included Pseudomonadota in sewage sludge (39.1%) and water (23.7%), while Actinomycetota prevailed in soil (38.5%). A multistage experiment, involving successive subcultures of environmental microbiomes exposed to polypropylene (PP), polyvinyl chloride (PVC), polycarbonate (PC), and polylactic acid (PLA), facilitated the assessment of MPs degradation processes. Analysis of carbonyl indices CIs and FTIR spectra revealed substantial structural changes in the treatment PVC-landfill soil, as well as in PLA- and PC-sludge enriched cultures. Further, using enriched cultures as a source of microorganisms, the study obtained 17 strains of plastic degraders from landfill soil, 14 from sewage sludge, and 6 from river water. Remarkably, similar bacterial genera were isolated across environmental microbiomes regardless of the MPs substrate used in enriched cultures. Among the 37 identified strains, Pseudomonadota predominated (64.86%) and were accompanied by Bacteroidota (16.22%), Actinomycetota (13.51%), and Bacillota (5.41%). This study highlights the complex relationship between microbiome diversity and the biodegradation efficiency of plastics, showing the potential for using microbial communities in the plastic pollution management.

Microbial Succession on Microplastics in Wastewater Treatment Plants: Exploring the Complexities of Microplastic-Microbiome Interactions

Despite some effectiveness of wastewater treatment processes, microplastics accumulate in sewage sludge and their further use may contribute to the release of plastic microplastics into the environment. There is an urgent need to reduce the amount of microplastics in sewage sludge. Plastic particles serve as solid substrates for various microorganisms, promoting the formation of microbial biofilms with different metabolic activities. The biofilm environment associated with microplastics will determine the efficiency of treatment processes, especially biological methods, and the mechanisms of organic compound conversion. A significant source of microplastics is the land application of sewage sludge from wastewater treatment plants. The detrimental impact of microplastics affects soil enzymatic activity, soil microorganisms, flora, fauna, and plant production. This review article summarizes the development of research related to microplastics and discusses the issue of microplastic introduction from sewage sludge. Given that microplastics can contain complex composite polymers and form a plastisphere, further research is needed to understand their potential environmental impact, pathogenicity, and the characteristics of biofilms in wastewater treatment systems. The article also discusses the physicochemical properties of microplastics in wastewater treatment plants and their role in biofilm formation. Then, the article explained the impact of these properties on the possibility of the formation of biofilms on their surface due to the peculiar structure of microorganisms and also characterized what factors enable the formation of specific plastisphere in wastewater treatment plants. It highlights the urgent need to understand the basic information about microplastics to assess environmental toxicity more rationally, enabling better pollution control and the development of regulatory standards to manage microplastics entering the environment.

Macrogenomes reveal microbial-mediated microplastic degradation pathways in the porcine gut: a hope for solving the environmental challenges of microplastics

It is increasingly recognized that microplastics (MPs) are being transmitted through the food chain system, but little is known about the microorganisms involved in MP degradation, functional biodegradation genes, and metabolic pathways of degradation in the intestinal tract of foodborne animals. In this study, we explored the potential flora mainly involved in MP degradation in the intestinal tracts of Taoyuan, Duroc, and Xiangcun pigs by macrogenomics, screened relevant MP degradation genes, and identified key enzymes and their mechanisms. The pig colon was enriched with abundant MP degradation-related genes, and gut microorganisms were their main hosts. The fiber diet did not significantly affect the abundance of MP degradation-related genes but significantly reduced their diversity. We identified a total of 94 functional genes for MP degradation and classified them into 27 categories by substrate type, with polystyrene (PS), polyethylene terephthalate (PET), and di(2-ethylhexyl) phthalate (DEHP) were the most predominant degradation types. The MP degradation functional genes were widely distributed in a variety of bacteria, mainly in the phylum Firmicutes and Bacteroidetes. Based on the identified functional genes for MP degradation, we proposed a hypothetical degradation mechanism for the three major MP pollutants, namely, PS, PET, and DEHP, which mainly consist of oxidoreductase, hydrolase, transferase, ligase, laccase, and isomerase. The degradation process involves the breakdown of long polymer chains, the oxidation of short-chain oligomers, the conversion of catechols, and the achievement of complete mineralization. Our findings provide insights into the function of MP degradation genes and their host microorganisms in the porcine colon.

Navigating the nexus: climate dynamics and microplastics pollution in coastal ecosystems

Microplastics (MPs) pollution is an emerging environmental health concern, impacting soil, plants, animals, and humans through their entry into the food chain via bioaccumulation. Human activities such as improper solid waste dumping are significant sources that ultimately transport MPs into the water bodies of the coastal areas. Moreover, there is a complex interplay between the coastal climate dynamics, environmental factors, the burgeoning issue of MPs pollution and the complex web of coastal pollution. We embark on a comprehensive journey, synthesizing the latest research across multiple disciplines to provide a holistic understanding of how these inter-connected factors shape and reshape the coastal ecosystems. The comprehensive review also explores the impact of the current climatic patterns on coastal regions, the intricate pathways through which MPs can infiltrate marine environments, and the cascading effects of coastal pollution on ecosystems and human societies in terms of health and socio-economic impacts in coastal regions. The novelty of this review concludes the changes in climate patterns have crucial effects on coastal regions, proceeding MPs as more prevalent, deteriorating coastal ecosystems, and hastening the transfer of MPs. The continuous rising sea levels, ocean acidification, and strong storms result in habitat loss, decline in biodiversity, and economic repercussion. Feedback mechanisms intensify pollution effects, underlying the urgent demand for environmental conservation contribution. In addition, the complex interaction between human, industry, and biodiversity demanding cutting edge strategies, innovative approaches such as remote sensing with artificial intelligence for monitoring, biobased remediation techniques, global cooperation in governance, policies to lessen the negative socioeconomic and environmental effects of coastal pollution.

Engineered biochar combined clay for microplastic biodegradation during pig manure composting

This study pursued to regulate bacterial community succession pattern and expedited biodegradation of microplastics (MP) during pig manure (PM) composting employing walnut shell biochar (WSB) and montmorillonite (M). The WSB with concentration of 0%, 2.5%, 5%, 7.5%, 10% and 12% along with 10% M participated into PM for 42 days compost to search the optimal solution. The results confirmed the most prosperous bacterial phylum consisted of Firmicutes (3.02%-91.80%), Proteobacteria (2.08%-48.54%), Chloroflexi (0-44.62%) and Bacteroidetes (0.85%-40.93%). The addition of biochar has dramatically arranged bacterial community at different stages of composting. Energy Dispersive Spectrometer (EDS) revealed that carbon element in MPs decreased since the chemical bond fracture, under the intervention of high-temperature composting and WSB, the carbon content of MPs was maximum reduced by 20.25%. Fourier transform infrared spectrum indicated that CC, C-O, C-H and -COOH abundance of MPs in 10% and 12% dose biochar addition sharply reduced, interestingly, explicating WSB and composting made MP biodegradable. This experiment possesses affirmatory practical meaning for elimination of potential hazards by composting.

Distribution patterns and environmental risk assessments of microplastics in the lake waters and sediments from eight typical wetland parks in Changsha city, China

The quality of water in urban parks is closely related to people's daily lives, but the pollution caused by microplastics in park water and sediments has not been comprehensively studied. Therefore, eight typical parks in the urban area of Changsha, China, were selected, and Raman spectroscopy was used to explore the spatial distributions and compositions of the microplastics in the water and sediments, analyze their influencing factors, and evaluate their environmental risks. The results showed that the abundances of surface water microplastics in all parks ranged from 150 to 525 n L-1, and the abundances of sediment microplastics ranged from 120 to 585 n kg-1. The microplastics in the surface water included polyethylene terephthalate (PET), chlorinated polyethylene (CPE), and fluororubber (FLU), while those in the sediments included polyvinyl chloride (PVC), wp-acrylate copolymer (ACR), and CPE. Regression analyses revealed significant positive correlations between human activities and the abundances of microplastics in the parks. Among them, the correlations of population, industrial discharge and domestic wastewater discharge with the abundance of microplastics in park water were the strongest. However, the correlations of car flow and tourists with the abundance of microplastics in park water were the weakest. Based on the potential ecological risk indices (PERI) classification assessment method, the levels of microplastics in the waters and sediments of the eight parks were all within the II-level risk zone (53-8,549), among which the risk indices for Meixi Lake and Yudai Lake were within the IV risk zone (1,365-8,549), which may have been caused by the high population density near the park. This study provides new insights into the characteristics of microplastics in urban park water and sediment.

Qualitative discrimination and quantitative prediction of microplastics in ash based on near-infrared spectroscopy

Microplastics are recognized as a new environmental pollutant. Researchers have detected their presence in waste incineration ash. However, traditional testing methods take a very long testing period. There is a lack of research on detecting microplastics in waste incineration ash. In this paper, a portable near-infrared spectra (NIRS) spectrometer was used for qualitative discrimination and quantitative prediction of microplastics in ash. A total of 84 sets of simulated ash samples containing different types (PP, PS, PE, and PVC) and contents (2.4 wt% - 20 wt%) of microplastics were used in the model. The results show the qualitative discrimination model using support vector machines (SVM) method with multiplicative scatter correction (MSC) preprocessing could effectively identify the microplastic types in the ash with 100% detection accuracy. Furthermore, the partial least squares regression (PLSR) model was effective in quantitatively predicting the content of microplastics in ash. The Rp2 of the PP, PS, PE, and PVC models are 0.95, 0.93, 0.89, and 0.95, respectively. The RPD of the PP, PS, PE, and PVC models are 3.97, 3.96, 2.89 and 5.02, respectively. This study shows that microplastics in ash can be detected rapidly and accurately using portable near-infrared spectrometers.

Closing the loop: A framework for tackling single-use plastic waste in the food and beverage industry through circular economy- a review

The escalating threat of plastic pollution necessitates urgent and immediate action, particularly within the food and beverage (F&B) industry, a significant contributor to single-use plastic waste (SUP). As the global population surges, so does the consumption of single-use plastics in the F&B sector, perpetuating a linear economy model characterized by a 'take, make, use, dispose' approach. This model significantly exacerbates plastic waste issues, with projections indicating an alarming increase in plastic outputs by 2050 if current practices continue. Against this backdrop, the circular economy presents a viable alternative, with its emphasis on resource retention, recovery, and the extension of product lifecycles. This study delves into the problems posed by single-use plastics, introduces the circular economy as a sustainable model, and explores effective strategies for the recycling and reuse of plastic waste within this framework. By examining the environmental impact of SUP in the F&B sector and advocating for the adoption of circular economy principles, this paper underscores a critical pathway towards sustainable solutions in the battle against plastic pollution. In conclusion, the transition to a circular economy, underpinned by global collaboration and the proactive implementation of supportive policies, is imperative for reducing the environmental footprint of single-use plastics and fostering a sustainable future.

Microorganism-mediated biodegradation for effective management and/or removal of micro-plastics from the environment: a comprehensive 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.

Progress in polystyrene biodegradation by insect gut microbiota

Polystyrene (PS) is frequently used in the plastics industry. However, its structural stability and difficulty to break down lead to an abundance of plastic waste in the environment, resulting in micro-nano plastics (MNPs). As MNPs are severe hazards to both human and environmental health, it is crucial to develop innovative treatment technologies to degrade plastic waste. The biodegradation of plastics by insect gut microorganisms has gained attention as it is environmentally friendly, efficient, and safe. However, our knowledge of the biodegradation of PS is still limited. This review summarizes recent research advances on PS biodegradation by gut microorganisms/enzymes from insect larvae of different species, and schematic pathways of the degradation process are discussed in depth. Additionally, the prospect of using modern biotechnology, such as genetic engineering and systems biology, to identify novel PS-degrading microbes/functional genes/enzymes and to realize new strategies for PS biodegradation is highlighted. Challenges and limitations faced by the application of genetically engineered microorganisms (GEMs) and multiomics technologies in the field of plastic pollution bioremediation are also discussed. This review encourages the further exploration of the biodegradation of PS by insect gut microbes/enzymes, offering a cutting-edge perspective to identify PS biodegradation pathways and create effective biodegradation strategies.

Catalytic Strategies for the Upcycling of Polyolefin Plastic Waste

Chemical upgrading of waste plastics is currently one of the most important methods for addressing plastic pollution. In comparison to the current methods of incineration or landfill, chemical upgrading enables the utilization of carbon and hydrogen elements in waste plastics as resources. This process strongly relies on efficient catalysts and reaction systems. Through catalyst design, waste plastics can be converted into fuels or chemicals under the optimized reaction conditions, extending their life cycles. In this review, we systematically discuss various chemical conversion methods for polyolefin waste plastics, which account for a large proportion of waste plastics. We further explore the remaining challenges and future development trends in this field, including improving product value through product engineering and shifting research perspectives to exploring the tolerance of catalysts toward impurities in practical waste plastic waste rather than using pure plastic feedstock.

Soils in distress: The impacts and ecological risks of (micro)plastic pollution in the terrestrial environment

Plastics have revolutionised human industries, thanks to their versatility and durability. However, their extensive use, coupled with inadequate waste disposal, has resulted in plastic becoming ubiquitous in every environmental compartment, posing potential risks to the economy, human health and the environment. Additionally, under natural conditions, plastic waste breaks down into microplastics (MPs<5 mm). The increasing quantity of MPs exerts a significant burden on the soil environment, particularly in agroecosystems, presenting a new stressor for soil-dwelling organisms. In this review, we delve into the effects of MP pollution on soil ecosystems, with a specific attention to (a) MP transport to soils, (b) potential changes of MPs under environmental conditions, (c) and their interaction with the physical, chemical and biological components of the soil. We aim to shed light on the alterations in the distribution, activity, physiology and growth of soil flora, fauna and microorganisms in response to MPs, offering an ecotoxicological perspective for environmental risk assessment of plastics. The effects of MPs are strongly influenced by their intrinsic traits, including polymer type, shape, size and abundance. By exploring the multifaceted interactions between MPs and the soil environment, we provide critical insights into the consequences of plastic contamination. Despite the growing body of research, there remain substantial knowledge gaps regarding the long-term impact of MPs on the soil. Our work underscores the importance of continued research efforts and the adoption of standardised approaches to address plastic pollution and ensure a sustainable future for our planet.