Aging-Induced Physicochemical Changes in Petroleum- and Biobased Microplastics Influence Depolymerization and Gut Microbiota in Tenebrio molitor Larvae
Aug 2026· Microorganisms· Vol 14, pp. 1700· 0 citations· 59 references
Medicine
TL;DR
Overall, aging modestly facilitated larval processing and partial depolymerization of both fossil-based and bio-based plastics, as reflected by increased plastic consumption, polymer chain scission, and surface oxidation, and enhanced the functional robustness of the larval gut microbiome.
Abstract
In this study, we evaluated the influence of physicochemical aging on the biological processing and depolymerization performance of polyethylene (PE) and polylactic acid (PLA) by Tenebrio molitor larvae, with the goal of improving insect-based plastic treatment strategies. PE and PLA subjected to a sequential freezing–ultraviolet aging protocol showed modest increases in total larval consumption (approximately 11% for PE and 10% for PLA) compared with pristine materials. Aging also accelerated the processes related to chemical depolymerization, as evidenced by Fourier transform infrared spectroscopy and scanning electron microscopy showing the formation of oxidized functional groups and surface structural deterioration, respectively. Gel permeation chromatography indicated significant reductions in molecular weight. In addition, thermogravimetric analysis was used to evaluate the changes in thermal stability associated with polymer degradation. Gut microbiome analysis revealed that plastic diets and aging collectively shaped microbial structure and compositional shifts, with deterministic ecological processes dominating community assembly. PE diets enriched Proteobacteria, while PLA diets enriched Firmicutes and Desulfobacterota. Notably, aging strengthened microbial cooperation and enriched key genera, such as Spiroplasma sp. and Lactobacillus sp., which are potentially associated with plastic-associated metabolic adaptation. Overall, aging modestly facilitated larval processing and partial depolymerization of both fossil-based and bio-based plastics, as reflected by increased plastic consumption, polymer chain scission, and surface oxidation. It also enhanced the functional robustness of the larval gut microbiome. These findings provide mechanistic insights into insect-mediated plastic processing systems, offering mechanistic guidance for future, combined plastic treatment strategies rather than an immediately scalable stand-alone solution.
The release of microplastics (MPs) and additives during plastic aging poses potential ecological risks, but the mechanistic links between these release processes and polymer degradation remain unclear. In this study, polyethylene (PE), polylactic acid/polybutylene adipate-co-terephthalate (PLA/PBAT), and polyvinyl chloride (PVC) were subjected to ultraviolet (UV) aging to systematically investigate the evolution of molecular structure, surface morphology, and mechanical properties. The release of MPs (10-500 μm) and phthalate esters (PAEs) was subsequently quantified by laser direct infrared (LDIR) spectroscopy and gas chromatography-mass spectrometry (GC-MS), respectively. Results revealed a general degradation pathway of chemical oxidation-structural reconstruction-mechanical failure. Photoaging-induced structural weakening, surface hardening, and material embrittlement not only promoted the generation and detachment of MPs but also facilitated PAE migration and release by increasing diffusion pathways and exposing the internal polymer matrix. The release behaviors of MPs and PAEs exhibited distinct patterns: MP release primarily resulted from matrix fragmentation and followed a power-law model (R2 > 0.99), whereas PAE release was governed by diffusion from a finite internal reservoir and was well described by a first-order kinetic model (R2 > 0.97). The three plastics showed different release preferences. PLA/PBAT and PE exhibited higher risks of MP release, while PVC presented a more prominent risk of PAE release.
Nina Yang, Yanyan Zhang, Cong Men et al.· Environmental Pollution· 0 citations
This study evaluated the potential reciprocal effects associated with interactions between lactic acid bacteria (LAB) with probiotic potential and two common microplastics, polyethylene terephthalate (PET) and poly(vinyl alcohol) (PVA), under controlled in vitro conditions. Bacterial growth, adhesion-related properties (autoaggregation, hydrophobicity, and coaggregation), safety-related traits (hemolytic activity and mucin degradation), antioxidant activity (ABTS scavenging and oxidative hemolysis inhibition), and anti-inflammatory activity (lipoxygenase and trypsin inhibition) were analyzed, along with structural and thermal changes in microplastics. Microplastic exposure did not affect bacterial growth (p > 0.05) but reduced autoaggregation and hydrophobicity (p < 0.05). None of the strains showed hemolytic activity, although mucin degradation increased. Antioxidant and anti-inflammatory activities decreased (p < 0.05). In addition, FTIR, thermal analysis, and microscopy revealed changes in the chemical composition, thermal behavior, and morphology of PET and PVA after interaction with LAB. Overall, microplastics modulate key probiotic-associated functions in LAB without compromising bacterial viability, while selected strains remain partially resilient and induce physicochemical changes in microplastic particles.
Diana G. Hernández-Aguilar, Lourdes Santiago-López, T. Madera-Santana et al.· ACS Food Science & Techn...· 0 citations
Excessive blooms of green macroalgae of the Ulva genus can lead to severe ecological and economic burdens. Therefore, strategies to circumvent these issues are required. As ulvan, the major sulfated polysaccharide extracted from Ulva, is biocompatible, biodegradable, and possesses sulfated functional groups and intrinsic film-forming capability, it is an attractive candidate for sustainable material development. In this study, ulvan was used to fabricate films and systematically evaluated for their mechanical performance and flexibility. Ulvan-based films were fabricated using glycerol as a plasticizer and tannic acid (TA) as a naturally derived functional modifier and bioactive component. The glycerol incorporation increased chain mobility and improved the polysaccharide matrix flexibility. TA introduced abundant phenolic hydroxyl groups capable of promoting hydrogen bonding within the polymer matrix, thereby contributing to enhanced intermolecular interactions. Spectroscopic and thermal analyses suggested enhanced intermolecular interactions and changes in thermal behavior as the TA content increased. Mechanical characterization revealed concentration-dependent changes in tensile strength and elongation behavior. TA incorporation increased the radical scavenging activity of the films in a concentration-dependent manner. MTT assays demonstrated the non-cytotoxicity of the developed films in human dermal fibroblasts and keratinocytes. Intracellular reactive oxygen species levels were further measured using DCFDA staining, which resulted in reduced intracellular oxidative stress levels. These findings demonstrate that tannic acid incorporation can be utilized to design eco-friendly polymer films with composition-dependent mechanical and biofunctional properties. The developed ulvan-based films may have potential applications in biomedical materials, including wound dressings, tissue interfaces, and protective bioactive coatings.
Nam-Gyun Kim, S. Moon, Tae-Hee Kim et al.· International Journal of Bio...· 0 citations
The aging of microplastics (MPs) inevitably occurs during sludge treatment, leading to the leaching of dissolved organic matter (DOM) and associated chemical additives. However, the impact and mechanism of aged leachate on anaerobic fermentation of waste activated sludge (WAS), particularly its ecological risks and implications for sludge resource recovery, remain poorly understood. This study investigated the effects of leachates prepared from photochemically (PC) and hydrothermally (HT) aged polyethylene (PE) MPs at an initial PE-MPs concentration of 5 g/L on short-chain fatty acids (SCFAs) production during WAS anaerobic fermentation. The results showed that PC and HT leachates reduced SCFAs production by 21% and 30.6%, respectively, and shifted the product composition from acetate-dominant to a mixed-acid profile. Biochemical analyses revealed that the aged leachates induced oxidative stress and inhibited protease and α-glucosidase activities, resulting in only 2.3%-6.0% protein degradation and a 23.1%-23.8% decrease in carbohydrate hydrolysis efficiency. Microbial community analysis further demonstrated that both PC and HT leachates reduced microbial diversity and the abundance of key hydrolytic genera, thereby compromising the functions of acid-producing and nitrogen-cycling bacteria. Analysis of leachate composition indicated that HT leachates released more oxygen-containing depolymerization products and additives, leading to stronger inhibition of microbial activity and hydrolysis processes. ECOSAR predictions suggested that several phenolic antioxidants and phthalate plasticizers may pose relatively high aquatic hazards. Their presence may partly contribute to the stronger biological inhibition observed in the aged-leachate treatments. These findings provide critical insights into the toxicity mechanisms of aged MP leachates in sludge fermentation systems.
Jie Wu, Jiating Hao, Yanwei Xue et al.· Journal of Hazardous Materia...· 0 citations
Plastic additives are emerging as active agents that shape the environmental impacts of microplastics. In this study, we investigated how a polyethylene microplastic formulation containing the commonly used UV filter benzophenone-3 (BP-3) and a calcium carbonate filler affects aging and biofilm colonization in freshwater. The additive-containing formulation altered the density and crystallinity of polyethylene particles and predisposed the material for faster surface transformation and formation of pits and cracks during aging. At the same time, it suppressed biofilm formation, reduced the development of extracellular polymeric substances by microorganisms, and specifically affected phototrophic microorganisms. Microbial community profiling revealed a shift from cyanobacteria-dominated biofilms to heterotrophic, chemically more resilient taxa, accompanied by enrichment of antibiotic resistance genes. Despite comparable genetic potential for polymer degradation, microbial activity was inhibited, indicating a trade-off between abiotic and biotic degradation. These results indicated that the tested additive-containing polyethylene formulation reduces microplastics stability and alters biofilm composition, highlighting the importance of considering additives in assessments of microplastic persistence and environmental effects.
B. Klun, Živa Zidar, Anja Klančnik et al.· Environmental Pollution· 0 citations
The development of bio-based polymeric materials from renewable waste streams represents a key challenge in sustainable material science. In this work, cellulose acetate obtained from grapevine lignocellulosic residues was used as a polymer matrix for composite films incorporating exhausted microalgal biomass of a Chlamydomonas reinhardtii culture as a biofiller. Microalgal residues are proposed to modulate intermolecular interactions and microstructural organization within cellulose acetate matrices, allowing for the tuning of thermal stability and mass transport properties. Films were prepared by solvent casting using glycerol as a plasticizer and investigated to elucidate structure–property relationships. Mechanical analysis shows that microalgal incorporation increases breaking stress while maintaining Young’s modulus and elongation at break. Fourier transform infrared (FTIR) spectroscopy reveals interactions among cellulose acetate, glycerol, and microalgal biomolecules. Differential scanning calorimetry (DSC) analysis indicates enhanced thermal stability, with thermal transitions shifting by more than 50 °C. Scanning electron microscopy (SEM) observations reveal a more compact microstructure. This structural reorganization results in increased surface wettability (contact angle decrease from ∼36° to ∼20°) and a significant reduction in water absorption (–57%), alongside increased mass transport properties. In particular, water vapor permeability increases by ∼40% and oxygen permeability by ∼14%. More broadly, this work establishes a scalable strategy to upcycle complementary bio-waste streams into multifunctional materials with tunable properties. The ability to simultaneously control barrier performance, wettability, and thermal stability highlights the potential of these systems for advanced sustainable packaging and functional coatings. Overall, this approach advances the rational design of high-performance bio-based materials, contributing to the transition toward circular and low-carbon material platforms.
