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. 2026 Apr 25;17:5716. doi: 10.1038/s41467-026-72354-3

Spontaneous efficient degradation of polyesters in soil by an enzyme@MOF platform

Jiaxin Cui 1,2, Xuan Gao 1, Jiangyue Yu 1, Shaochun Wu 1, Chaonan Jin 3, Min Jiang 4, Weiliang Dong 4, He Huang 5,✉, Michael J Zaworotko 6,✉, Zhenjie Zhang 7,8, Yao Chen 1,2,7,✉
PMCID: PMC13323979  PMID: 42034609

Abstract

Waste plastics represent a serious and growing environmental problem. Whereas biodegradable polyesters such as polycaprolactone (PCL) and polylactic acid (PLA) offer a potential solution, their spontaneous degradation takes up to 3 years in the field. Industrial composting, an alternative approach, is labor and energy intensive as well as being prone to cross-contamination by other plastics. In recent years, exploitation of bespoke enzyme systems has been shown to accelerate composting but these innovative approaches are thus far unsuitable for field deployment. We address this challenge by developing an enzyme@MOF platform to fabricate composite plastics through multiple industry-compatible processing techniques, including screw extrusion, 3D printing, and solution casting. The top performing enzyme@MOF, lipase@MIL-88A, degrades PCL and is fast (<10 days), low cost ($11/kg) and acid-responsive. The latter feature enables controlled degradation of the MOF to release lipase in the field upon exposure to weakly acidic rainwater, entirely avoiding the need for collection and composting. Further, the degradation products of lipase@MIL-88A are biocompatible and were found to fertilize plant growth. The broad utility of the enzyme@MOF approach is further demonstrated by its successful application to multiple polyester plastics, such as PLA, PET, PBAT, PBS, and PEF.

Subject terms: Pollution remediation, Polymers

Waste plastics pose an escalating environmental challenge, and existing disposal solutions remain inadequate. Industrial composting is labor and energy intensive, while engineered enzyme systems have yet to be deployable outside controlled facilities. In this study, the authors introduce an enzyme@MOF platform that can be incorporated into biodegradable plastics using industry-compatible processes. This strategy enables controlled, rain-triggered degradation under weakly acidic conditions, eliminating the need for collection or specialized composting. Notably, the resulting degradation products are biocompatible and even promote plant growth, highlighting the platform’s potential for sustainable, field-scale plastic remediation

Introduction

More than 400 million tons of plastic are produced annually, but less than 10% are suitable for recycling, resulting in “white pollution” that causes environmental contamination and endangers human health1–4. Biodegradable plastics such as polyesters, which can be degraded by microorganisms or enzymes, have emerged as a promising solution5,6 and are expected to account for 40% of the global plastics market by 20307. Notably, polycaprolactone (PCL) and polylactic acid (PLA), which exhibit excellent processability and water resistance, are widely used in biomaterials and sustainable packaging, with > 800,000 tons produced annually8,9. However, spontaneous degradation of polyesters is slow in the field (1–3 years), and accumulation of plastic debris can lead to reduced soil fertility or enter the human body through the food chain10,11. Although industrial composting can facilitate polyester degradation, it requires harsh degradation conditions, is labor-consuming, and has cross-contamination issues12,13. Further, the global composting infrastructure, even in the United States, is infit for purpose14,15. Consequently, the preponderance of biodegradable products are ultimately diverted to landfill, exacerbating their environmental footprint. In this context, the development of bioplastic composites that can be degraded in the natural environment would represent a disruptive new technology.

It has been reported that the use of enzyme systems can accelerate composting of plastics. The state-of-art approaches to produce enzyme-containing plastics include engineering enzymes or adding enzyme protectants (Fig. 1a, b), which can enhance enzyme stability and processability and promote degradation of composite plastics under composting conditions16,17. Nevertheless, significant challenges remain, in particular ensuring that the enzyme is leak-free during the lifetime of the plastic and that it is released after the plastic is discarded to achieve rapid degradation in the field. Enzyme immobilization can enhance enzyme stability and modulate reaction processes, providing new opportunities for biodegradable plastics18,19. Metal-organic frameworks (MOFs) have been exploited for enzyme immobilization and used as high-performance enzyme carriers for biocatalysis20,21. Further, several MOFs can be prepared on a large scale at relatively low cost. In addition, thanks to the dynamic nature of coordination bonds, MOFs can be designed to respond to environmental conditions, thereby adjusting enzyme release rates and enabling control over the biodegradation of plastics. For instance, natural rainwater contains dissolved atmospheric carbon dioxide (pH = 5.6–7.0)22, and, after it infiltrates soil, the pH value of topsoil, where most plastic waste will be located, is acidic. Therefore, MOFs that exhibit acid-responsive degradation are, in principle, ideal enzyme carriers to degrade plastics upon exposure to rainwater, entirely avoiding the need for collection and composting. Moreover, some metal ions (e.g., Fe3+, Zn2+, Ca2+) released by decomposition of MOF carriers might be beneficial as enzyme activators to boost activities and will ultimately be absorbed by plants to promote plant growth23,24.

Fig. 1. Strategies for enhancing enzymatic plastic degradation.

Fig. 1

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Illustration of a enzyme engineering, b enzyme protectant addition, and c the enzyme@MOFs approach reported herein for plastic degradation.

To address this matter, we report herein a biocompatible MOF-based enzyme immobilization platform (enzyme@MOFs) and the results of our study on its efficacy for polyester degradation, its ability to stabilize lipase, and its acid-responsiveness to rainwater. Figure 1c illustrates the difference between the approach detailed herein and conventional enzyme-assisted approaches.

Results

Design of enzyme@MOF platform for polyester depolymerization

Lipase is one of the most widely used enzyme families in industry and can catalyze hydrolysis, transesterification, and ester synthesis reactions25,26. To select a biocatalyst to degrade PCL, we first screened the activity of five lipases through a standard enzyme activity evaluation assay using p-NPA as a substrate under varying pH and temperature conditions. The results revealed that PS lipase (PS) and FM-10 lipase (FM-10) exhibited the best catalytic and hydrolytic activity with optimal reaction conditions of T = 40-55 °C and pH = 6.8 (Supplementary Figs. 1–4). Considering the much lower cost of commercial FM-10 (9100 $/t) vs. PS (2.766 million $/t), FM-10 was chosen for use in a lipase@MOF platform to enable biodegradable plastic fabrication (Fig. 2a).

Fig. 2. Characterization and process optimization of FM-10@MIL-88A&PCL.

Fig. 2

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a Preparation of FM-10@MIL-88A&PCL. b Catalytic rate (bar chart) and enzyme loading amount (line chart) of FM-10@MIL-88A at different initial enzyme concentrations. c SEM image of FM-10@MIL-88A. d FT-IR spectra of FM-10, MIL-88A, and FM-10@MIL-88A. e PXRD patterns of PCL, FM-10@MIL-88A, and FM-10@MIL-88A&PCL. f Cross-sectional fractured-surface SEM images of FM-10@MIL-88A&PCL. g A magnified image of the fractured region, showing the presence of FM-10@MIL-88A particles. h Cross-sectional CLSM image of FM-10@MIL-88A&PCL, showing FITC-labeled FM-10@MIL-88A (green) within the PCL matrix. i Stress-strain curves of PCL and FM-10@MIL-88A&PCL. The error bar of the sample refers to the standard deviation of three groups prepared at different times (n  =  3). Source data are provided as a Source Data file.

With respect to a suitable MOF, we selected MIL-88A as it is comprised of the earth-friendly components fumaric acid, which is pharmaceutically approved for use in drug products, and Fe(III), which is an essential nutrient for plant growth and involved in important chemical reactions such as photosynthesis and respiration27. Moreover, both fumaric acid and Fe(III) can be absorbed by plants to promote plant growth28,29. MIL-88A can be prepared at room temperature in water, facilitating large-scale, low-cost manufacture of the MOF and enzyme@MOF30. The biocompatibility of MIL-88A was evaluated by a methyl thiazolyl tetrazolium (MTT) assay, which revealed that even at a concentration of 600 μg/mL of MIL-88A, cell survival rate was still greater than 99% (Supplementary Fig. 5). Importantly, MIL-88A was also found to undergo acid-triggered degradation (5.6–6.8), suggesting the possibility of controlled release by rainwater in the field (Supplementary Figs. 6 and 7). Meanwhile, MIL-88A was found to be stable in neutral water and common organic solvents (Supplementary Figs. 8 and 9). The latter enables its utility to hybridize and shape polymers (e.g., PCL).

Employing a one-pot in-situ encapsulation method at an initial enzyme concentration of 8 mg/mL, we successfully immobilized FM-10 into MIL-88A, achieving both a high enzyme loading of 0.43 g/g and optimal catalytic activity (Fig. 2b). Scanning electron microscopy (SEM), powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM) (Fig. 2c and Supplementary Figs. 10 and 11) revealed that crystallinity and morphology of MIL-88A was retained in FM-10@MIL-88A31. Compared to pristine MIL-88A, the new absorption peaks observed at 3250 cm⁻¹ and 2920 cm⁻¹ in the Fourier transform infrared (FT-IR) spectrum of FM-10@MIL-88A can be attributed to the presence of FM-10 (Fig. 2d). In addition, confocal laser scanning microscope (CLSM) images demonstrated that fluorescein isothiocyanate (FITC)-labeled FM-10 (green) was uniformly dispersed in MIL-88A (Supplementary Fig. 12). It was also found that FM-10@MIL-88A maintained excellent catalytic activity after treatment with various organic solvents (Supplementary Fig. 13). Additionally, the degradation profile and enzyme release kinetics of the composite were evaluated. The composite exhibited a degradation rate of 65% within 24 h, accompanied by 75% enzyme release (Supplementary Fig. 14). Notably, the overall catalytic activity progressively increased with the cumulative enzyme release (Supplementary Fig. 15). Therefore, MIL-88A was deemed suitable for use as a functionalized enzyme carrier to enhance FM-10 in terms of both stability and activity.

Subsequently, we embedded FM-10@MIL-88A into PCL, forming the composite FM-10@MIL-88A&PCL as verified by several tests. PXRD patterns indicated that FM-10@MIL-88A&PCL had distinct peaks at 21.2° and 23.5° corresponding to the (110) and (200) planes of PCL32 as well as peaks corresponding to MIL-88A (Fig. 2e). Cross-sectional SEM analysis revealed embedding of FM-10@MIL-88A within the PCL matrix (Fig. 2f, g and Supplementary Figs. 16–18). CLSM images further confirm the distribution of FM-10@MIL-88A within PCL (Fig. 2h). Stress‑strain measurements showed that the mechanical properties of the composites varied with FM‑10@MIL‑88 A content, displaying an initial enhancement followed by a decline. While a 4 wt% loading induced a negligible change (<5%) relative to pure PCL, increasing the filler to 6 wt% resulted in a significant deterioration of mechanical performance, with key parameters decreasing by more than 10%. (Fig. 2i). To explore the generality of enzyme-embedded polyesters of other rainwater-responsive carriers, such as earth-friendly Zn- or Ca-based MOFs, we selected NKMOF-101 (Zn), ZPF-2 (Zn), ZIF-8 (Zn), Ca-BDC (Ca), and ZIF-L (Zn) to immobilize enzymes via our in-situ one-pot reaction under mild conditions (room temperature and water). It was found that ZIF-8 degraded in neutral water (pH = 7.0). The remaining MOFs exhibited acid responsiveness (Supplementary Figs. 19–23), indicating that MOFs can be utilized to develop a range of composite plastics that can be degraded in various pH environments. PXRD and CLSM data verified the successful construction of FM-10@MOFs24,33–35 (Supplementary Figs. 24 and 25). The FM-10@MOFs exhibited excellent catalytic activities for the hydrolysis of esters, except for FM-10@NKMOF-101 and FM-10@ZIF-8 (Supplementary Fig. 26). These FM-10@MOFs composites were also resistant to organic solvents (Supplementary Figs. 27–29), facilitating polymer composite formation as above. We selected Ca-BDC, ZPF-2, and ZIF-L for subsequent studies. PXRD patterns confirmed that the FM-10@MOFs were successfully embedded into PCL (Supplementary Fig. 30). In addition, in vitro studies addressed the cytotoxicity of FM-10@MOFs&PCL. The relative cell survival rates (Supplementary Fig. 31) of all four types of composite materials after co-cultivation with cells were higher than 90%, comparable to commercial food packaging.

Biodegradability of enzyme-embedded polyesters

The mass changes of the composite plastic before and after hydrolysis were determined, as well as the relationship between the amount of FM-10@MIL-88A and the degradation rate of the composite plastic. When the doping of the composite biocatalyst reached 4 wt%, FM-10@MIL-88A&PCL achieved over 98% hydrolysis within 24 h (Supplementary Fig. 32). By contrast, MIL-88A&PCL (without FM‑10) showed minimal degradation of approximately 2.5% under identical conditions, attributable to the acid-induced decomposition of the MOF framework itself (Supplementary Figs. 33 and 34). However, further increasing the loading to 6 wt% failed to enhance the 24‑h degradation efficiency while significantly deteriorating the composite’s mechanical properties, establishing 4 wt% as the optimal loading that balances high catalytic performance with mechanical properties. Subsequent thermal characterization of the composite film at this optimal loading confirmed that the incorporation of the biocatalyst did not significantly alter the intrinsic properties of the PCL matrix. Thermogravimetric analysis (TGA) showed nearly identical curves for the composite and pure PCL, with the main decomposition step for both commencing at approximately 350 °C, indicating no substantial effect on thermal stability (Supplementary Fig. 35). Furthermore, differential scanning calorimetry (DSC) revealed that the melting point (Tm) and melting enthalpy (ΔHm) of the composite closely matched those of pure PCL (Supplementary Fig. 36). This result confirms that the addition of the biocatalyst had no significant influence on the crystallinity or crystalline structure of PCL. Other composite plastics also showed > 95% hydrolysis within 24 h (Fig. 3a). In addition, we tested the effect of solution pH on the degradation efficiency of the composite plastic. At pH 5.6–6.8, the degradation of FM-10@MIL-88A&PCL remained constant (Supplementary Fig. 37). In addition, to further confirm the necessity of encapsulation, we also investigated the degradation efficiency of composite plastics prepared by different production methods: direct addition of FM-10 (FM-10&PCL), physical mixing of FM-10 and MIL-88A (FM-10-MIL-88A&PCL), and FM-10@MIL-88A (FM-10@MIL-88A&PCL) fabricated via 3D printing, hot-melt molding, and solvent casting. To ensure the melting and printability of the PCL composite, a mixture of PCL and FM-10@MIL-88A was heated in a nozzle (90 °C) for 15 min and then extruded to obtain the 3D printed composite plastic (Fig. 3b). We found that the degradation efficiency of FM-10@MIL-88A&PCL was unaffected by the preparation method. In contrast, the degradation efficiencies of both FM-10&PCL and FM-10-MIL-88 A&PCL were significantly reduced when prepared by 3D printing, which is directly attributed to enzyme deactivation caused by the high processing temperatures (Fig. 3c–e). These results demonstrate that encapsulation within MIL‑88 A is essential to preserve the enzymatic activity during high‑temperature fabrication processes. Additionally, the other composite materials also exhibited excellent thermal stability (Supplementary Fig. 38). To validate the potential for industrial-scale production applications, we conducted an amplification test of FM-10@MIL-88A. The crystallinity and morphology of batch-produced FM-10@MIL-88A remained consistent with the original material, as confirmed by XRD and SEM characterization (Fig. 3f, g and Supplementary Figs. 39 and 40). Subsequently, we successfully embedded FM-10@MIL-88A into the PCL matrix to fabricate the composite plastic using screw extrusion processing (Fig. 3h and Supplementary Fig. 41). Notably, while achieving over 98% hydrolysis within 72 h (Fig. 3i), the composite plastic maintained near-cost parity with pure PCL (only a 4.8% cost increase). To further validate the generality of the enzyme@MOF platform, we investigated another commonly used biodegradable plastic, PLA, which also suffers from slow degradation. We incorporated proteinase K (prok), a well‑established enzyme for PLA degradation16 with superior performance to lipase FM‑10 (Supplementary Fig. 42), into the PLA matrix to generate prok@MIL‑88 A&PLA using conventional solvent casting techniques. The composite achieved > 96 % depolymerization after 48 h in buffer at 45 °C (Supplementary Fig. 43). Directly preparing this composite plastic by hot-melting processing (160 °C) resulted in a significant loss of degradability due to alterations in the enzyme’s secondary structure (Supplementary Fig. 44), so we developed a masterbatch approach using sodium alginate, a natural polysaccharide soluble in aqueous solutions and FDA-approved food additives, to improve the enzyme’s thermal tolerance (Supplementary Fig. 45). After 160 °C treatment, prok@MIL-88A@SA&PLA demonstrated significantly enhanced degradation relative to other composite plastics containing embedded additives, with approximately 96.0% degradation efficiency within 48 h (Supplementary Fig. 46). This high efficiency is enzyme‑specific, as a control sample containing only MIL‑88 A@SA in PLA showed merely 3.4 % mass loss under the same conditions, attributable to the acidic decomposition of the MIL-88A@SA (Supplementary Fig. 47). Importantly, the incorporation of prok@MIL‑88 A@SA (5 wt %) largely maintained the mechanical and thermal properties of the PLA matrix. Tensile testing revealed a marginal increase of ~4.4% in tensile strength and a slight decrease of ~8.2% in elongation at break. (Supplementary Fig. 48). Thermally, the complete suppression of the cold‑crystallization peak in the composite indicates that the filler acts as an efficient nucleating agent, promoting crystallization during cooling. Nevertheless, the melting temperature and melting enthalpy remained comparable to those of neat PLA, confirming that the overall crystallinity was largely preserved despite the accelerated crystallization kinetics (Supplementary Fig. 49). Furthermore, TGA confirmed that the thermal decomposition behavior of the composite was largely similar to that of neat PLA, with both exhibiting a major decomposition step starting around 350 °C (Supplementary Fig. 50). Having successfully demonstrated the efficacy of the enzyme@MOF strategy for PLA, we next explored its generalizability to other major commercial polyesters. We constructed four composite plastics using cutinases with distinct substrate specificities. Specifically, leaf-branch compost cutinase (LCC) was used to degrade Polyethylene Terephthalate (PET) and Poly(butylene adipate-co-terephthalate) (PBAT), while Humicola insolens cutinase (HiC) was used to degrade Polybutylene Succinate (PBS) and Polyethylene Furanoate (PEF)36–39. The resulting composites, LCC@MIL‑88 A&PET, LCC@MIL‑88 A&PBAT, HiC@MIL‑88 A&PBS, and HiC@MIL‑88 A&PEF, all achieved degradation efficiencies exceeding > 95% within 36 h (Supplementary Figs. 51 and 52). These consistent results across different polyester–enzyme pairs confirm that the enzyme@MOF encapsulation approach offers general utility for developing programmable, degradable plastic materials.

Fig. 3. Evaluation of the degradation of composite plastics prepared using different production methods.

Fig. 3

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a Degradation efficiency of FM-10@MOFs&PCL. All composite plastics were degraded by over 95% within 24 h (40 °C, pH = 6.8). b Composite plastics containing FM-10@MIL-88A were fabricated by a 3D printer. c The 3D-printed composite plastic degrades at 40 °C (pH = 6.8 buffer, 48 h). d Effect of preparation method on degradation of FM-10&PCL, FM-10-MIL-88A&PCL, and FM-10@MIL-88A&PCL. e The impact of temperature on the catalytic activity of FM-10, FM-10-MIL-88A, and FM-10@MIL-88A. f PXRD pattern and g image of FM-10@MIL-88A synthesized in 42.6 g scale. h Manufacturing of composite plastics through single-screw extrusion and pelletizing. i Hydrolysis testing of pelletized composite plastics. The error bars for the sample represent the standard deviation across three groups prepared at different times (n  =  3). Source data are provided as a Source Data file.

The water stability of plastics is relevant to practical applications and to enabling its ultimate degradation. The ideal scenario would be a PCL variant that is stable under everyday usage but readily degrades in the field. We therefore studied the effect of embedded FM-10 on promoting the degradation of PCL by conducting hydrolysis experiments upon PCL, FM-10&PCL, and FM-10@MIL-88A&PCL. The photographs and mass change curves after hydrolysis at different time intervals revealed significantly enhanced degradation of the composite plastics (embedded with enzyme) vs. PCL (Fig. 4a–c). Hydrolysis testing showed that the mass loss of FM-10&PCL was up to 39.5%, while the mass of FM-10@MIL-88A&PCL remained nearly unchanged after 7 days (Fig. 4d and Supplementary Fig. 53a, b). Notably, the degradability of FM-10@MIL-88A&PCL in buffer (40 °C, pH = 6.8) was unchanged after 7 days of immersion in water (Supplementary Fig. 53c). In addition, the stress-strain curves confirmed that the mechanical properties of FM-10&PCL decreased significantly after 7 days of immersion in water (Fig. 4e), while FM-10@MIL-88A&PCL remained nearly unchanged. The premature depolymerization of FM-10&PCL can be attributed to the accessibility of the polymer chains to the enzyme’s active site during material use. By encapsulating the enzyme with MIL-88A, controllable degradation of the composite plastic was achieved (Fig. 4f, g). The storage stability of the composite was then tested under realistic ambient conditions (room temperature, 30–65% RH) for five weeks, and the results showed no measurable mass loss and well‑maintained mechanical properties (Supplementary Figs. 54 and 55). Notably, even under extreme humidity (> 95% RH) for five days, the composite exhibited excellent stability (Supplementary Fig. 56). Furthermore, the degradation ability of FM-10@MIL-88A&PCL upon hydrolysis remained > 95% after 3 months of storage in air, whereas the performance of FM-10&PCL decreased dramatically after 2 weeks of storage under the same conditions (Supplementary Fig. 57), indicating excellent daily use stability of FM-10@MIL-88A&PCL.

Fig. 4. Comparison of degradation of plastic films in buffers.

Fig. 4

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Hydrolysis of a FM-10&PCL and b FM-10@MIL-88A&PCL (40 °C, pH = 6.8 buffer). FM-10@MIL-88A&PCL degrade > 98% in 24 h. c Weight loss rates of PCL, FM-10&PCL, and FM-10@MIL-88A&PCL (40 °C, pH = 6.8 buffer). d Mass change rates for FM-10&PCL and FM-10@MIL-88A&PCL immersed in water (room temperature, pH = 7.0). e Stress-strain curves of FM-10&PCL and FM-10@MIL-88A&PCL after being immersed in water for 7 days. The hydrolysis mechanisms in f FM-10&PCL and g FM-10@MIL-88A&PCL. h FT-IR spectra of FM-10@MIL-88A &PCL at different hydrolysis times. i GPC chromatogram of PCL and FM-10@MIL-88A&PCL hydrolyzed products. The main peak of PCL disappeared, and the molecular weight of the hydrolyzed product was <1000 g/mol. j HPLC chromatogram of hydrolysis products and 6-hydroxyhexanoic acid standard sample. The error bars for the sample represent the standard deviation across three groups prepared at different times (n  =  3). Source data are provided as a Source Data file.

The properties of composite plastic after decomposition were next explored. First, Fourier Transform Infrared (FT-IR) Spectrophotometer spectra of FM-10@MIL-88A&PCL were collected after different degradation times (Fig. 4h). Peaks corresponding to asymmetric and symmetric stretching vibrations of methyl groups were detected at 2956 cm−1 and 2873 cm−1, respectively. The 1220 cm−1 peak can be attributed to C-O-C symmetric elongation. Absorption peaks within the 3500-3250 cm−1 range observed in degraded FM-10@MIL-88A&PCL are attributed to the hydroxyl group of -COOH and -OH moieties. Additionally, all films displayed a peak at 1723 cm−1 from the C = O stretching vibration of ester groups. After degradation for 18 h, a new peak emerged at 1698 cm−1, suggesting degradation to generate carboxyl end groups40–42. The relative molecular weight of FM-10@MIL-88A&PCL degradation products was assessed by gel permeation chromatography (GPC). The results revealed that the composite plastic was nearly completely degraded after 24 h, and the molecular weight of the hydrolyzed products was reduced to <1,000 Da (Fig. 4i). The water-soluble products of FM-10@MIL-88A&PCL degradation were analyzed using ultraviolet–visible (UV-Vis) spectroscopy (Supplementary Fig. 58). The hydrolysis product had an absorption peak close to 202 nm, consistent with 6-hydroxyhexanoic acid. High-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) testing verified the presence of 6-hydroxyhexanoic acid in the hydrolysis product (Fig. 4j and Supplementary Fig. 59), indicating that the hydrolysis products of FM-10@MIL-88A&PCL were 6-hydroxyhexanoic acid and its oligomers.

Beyond the significant costs involved, the enzymatic degradation of recycled plastics is further constrained by multiple factors. For instance, the hydrolysis efficiency of PCL was significantly limited by film thickness in an enzymatic solution (PCL-FM-10), whereas it was unaffected with FM-10@MIL-88A&PCL (Supplementary Fig. 60). This thickness-dependent inhibition stemmed from restricted enzyme diffusion within the polymer matrix. Moreover, the hydrolysis efficiency of PCL decreased by over 68% when the buffer volume was increased from 30 mL to 900 mL, which further highlights the volume-dependent degradation effect inherent in the free enzyme system (Supplementary Fig. 61). The observed reduction in degradation efficiency occurred because enzyme-substrate interactions relied entirely on random collisions mediated by Brownian motion. In contrast to free enzyme degradation, the embedded degradation approach overcame challenges in plastic waste recovery, maintaining consistent degradation efficiency irrespective of buffer volume or film thickness (Supplementary Fig. 62).

Overall, these results indicate that the degradation efficiency of composite plastic prepared by embedding the enzyme directly in polyester is severely limited by the external environment due to poor enzyme stability. In addition, due to direct enzyme contact with the polyester, FM-10&PCL undergoes premature depolymerization during its service life. In contrast, MIL-88A encapsulation not only significantly enhanced enzyme stability against external environments but also effectively controlled enzyme-polymer interaction, preventing premature degradation. Therefore, FM‑10@MIL‑88 A&PCL is a biodegradable plastic suitable for a wide range of non-acidic ambient conditions, offering a controlled life cycle that ensures stability in use and enables rapid depolymerization in acidic environments after disposal.

Field depolymerization of FM-10@MIL-88A&PCL

While PCL can be fully degraded by soil microorganisms, its semi-crystalline nature results in a prolonged degradation cycle43. The best-performing composite, FM-10@MIL-88A&PCL, was found to rapidly depolymerize due to the synergistic effect of microorganisms and enzymes (Fig. 5a). In outdoor soil degradation tests (short periods of precipitation were present during the test), PCL plastic degrades slowly, while the composite plastic degraded by > 90% in just 7 days, and almost completely degraded within 10 days (Fig. 5b, c). We noted that the degradation rate of the composite plastic accelerated significantly on the third day promoted by continuous decomposition of MIL-88A and the consequent release of enzyme molecules and enzyme activator Fe3+ (Supplementary Figs. 63–65). Additionally, we found that FM-10@MIL-88A&PCL was nearly completely degraded within 18 h in a simulated industrial composting environment, while PCL only degraded ~5% under the same conditions (Supplementary Fig. 66). Similarly, PLA degradation tests under realistic conditions showed equally promising results. Soil burial tests over 30 days demonstrated > 95% degradation for prok@MIL-88A@SA&PLA, compared to only less than 6% degradation of pure PLA (Supplementary Fig. 67). Under composting conditions over 48 h, the composite material achieved near-complete degradation, whereas pure PLA showed minimal degradation below 3% (Supplementary Fig. 68). Further, we studied the effects of decomposition products on soil. Considering that both Fe3+ and fumaric acid can be absorbed by plants to promote plant growth, we evaluated the degradation products of FM-10@MIL-88A&PCL through a maize growth experiment. The results revealed that after 2 weeks of cultivation, compared to the control group, the experimental group had increased fresh weight, dry weight, root length, stem height and leaf length by approximately 43.5%, 52.2%, 18.1%, 26.2%, and 28.3%, respectively (Fig. 5d–f and Supplementary Fig. 69). The chlorophyll content in the seedlings of the test group rose by approximately 15.0% compared to the control group (Fig. 5g). These results demonstrate that the products of composite film degradation can enhance nutrient uptake and stimulate plant growth.

Fig. 5. PCL and FM-10@MIL-88A&PCL degradation in the field.

Fig. 5

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a Schematic diagram of PCL and FM-10@MIL-88A&PCL degradation in outdoor soil. Images of b PCL and c FM-10@MIL-88A&PCL degradation in soil at 0, 3, 7, and 10 days. Undegraded plastics were collected from the soil using 35-mesh for observation. FM-10@MIL-88A&PCL achieved near-complete degradation in an outdoor soil environment within 10 days. d Digital images of maize seedlings after 2 weeks of growth in the control group and soil containing FM-10@MIL-88A&PCL degradation products. Quantitative analysis of maize seedling parameters including e weight, f length, and g chlorophyll content. Student’s t-test (two-sided) was used for statistical analysis. No adjustments were made for multiple comparisons. P-values are indicated in the figures, significance levels are denoted as follows: P < 0.05 (*), P < 0.01 (**), P < 0.001 (***). Source data are provided as a Source Data file.

Discussion

In conclusion, we introduce herein a new class of composite plastic comprising polyesters and enzymes@MOFs platform, which combines ease of fabrication, cost-effectiveness (4.8% cost increase), and environmental tolerance to enable spontaneous degradation. We demonstrate that MOFs can preserve enzyme activity during diverse industry-compatible processing techniques (screw extrusion, 3D printing, and solution casting) and enable pH-responsive enzyme release in environmental conditions (e.g., rainwater, soil), thereby promoting the degradation of waste plastics in the field. The composite plastics exhibited mechanical properties, stability, and cytocompatibility consistent with PCL itself. Further, whereas the composite variant of PCL was determined to be stable in daily use (excellent storage and water stability), it spontaneously degraded in the field after disposal (near complete degradation within 10 days), entirely avoiding the need for collection, sorting, and composting. The organic compounds and metal ions produced during degradation were beneficial for plant growth. For high-melting-point PLA plastics, the incorporation of SA as a cofactor significantly enhanced enzymatic tolerance, facilitating efficient plastic degradation. Further, our approach offers a wide scope for bulk manufacture, lower cost of ingredients, and better degradation efficiency.

Methods

Materials

Aspergillus niger Lipase (AS), Porcine pancreatic Lipase (PP), Lipase from Burkholderia cepacia (PS), Candida antarctica Lipase B (CA), proteinase K (prok), and PCL (30–80 kDa) were purchased from Sigma-Aldrich. PLA (80–150 kDa) was purchased from Guangdong Zhen Tai Biotechnology Co., Ltd. FM-10 was purchased from VLAND BIOTECH INC. The LCC and HiC cutinases were obtained and prepared as described in refs. 36,37. Except for the special description, all materials, including solvents throughout the experiments, were purchased from commercial sources and used as received without further purification.

Synthesis Method for MIL-88A and FM-10@MIL-88A

The ferric chloride hexahydrate solution (12.5 mg, 1 mL) was mixed with 3 mL of aqueous solution that included monosodium fumarate (25.5 mg) and FM-10 (0 mg/mL, 2 mg/mL, 4 mg/mL, 6 mg/mL, 8 mg/mL, 10 mg/mL). The mixture was kept still for 60 min at room temperature. The MIL-88A and FM-10@MIL-88A were obtained by centrifugation and washed with water.

Preparation of PCL membrane

100 mg ± 0.5 mg of PCL was dissolved in toluene at a concentration of 3 wt% and stirred for 60 min until completely dissolved. The solution was then directly cast into glass culture dishes (d = 60 mm), and the PCL membrane was obtained after the solvent completely evaporated.

Preparation of FM-10@MOFs&PCL sample or FM-10&PCL membrane

FM-10@MOFs or FM-10 were added to PCL (dissolved in toluene or heated to 90 °C to melt), stirred for 60 min, and poured directly into culture dishes (d = 60 mm). Allow the solvent to evaporate completely or the melt to cool naturally to obtain a membrane of FM-10@MOFs&PCL or FM-10&PCL.

3D printing of FM-10@MOFs&PCL

Composite plastics were prepared using the Regenovo 3D Bio-Architect®WS 3D printing instrument (equipped with an ultra-high-temperature nozzle). Printing temperature 90 °C, advance speed 3 mm/s, needle size (0.6 mm).

Hydrolysis experiment

PCL-based plastics, including neat PCL, FM-10&PCL, FM-10-MIL-88A&PCL, and FM-10@MIL-88A&PCL, were degraded in sodium phosphate buffer (30 mL, 50 mM, pH 6.8) at 40 °C for 24 h, while the other five types of plastics were degraded at 45 °C.

Effect of solution volume on degradation efficiency

With the same amount of enzyme, PCL-FM-10 and FM-10@MIL-88A&PCL were placed in 30 mL, 90 mL, and 900 mL of buffer and degraded at 40 °C for 24 h. The degradation efficiency was determined by weighing the remaining sample.

Effect of film thickness on degradation efficiency

100 mg ± 0.5 mg of PCL or FM-10@MIL-88A&PCL was dissolved in toluene at a concentration of 3 wt% and stirred for 60 min until completely dissolved. The solution was then poured into glass petri dishes of different diameters (d = 45, 60, and 75mm) and the films of different thicknesses were obtained after complete evaporation of the solvent. With the same amount of enzyme, the different diameters of PCL-FM-10 and FM-10@MIL-88A&PCL were placed in buffer (30 mL, 50 mM, pH = 6.8) and degraded at 40 °C for 24 h. The degradation efficiency was determined by weighing the remaining sample.

Soil degradation experiment

100 ± 0.5 mg of PCL or FM-10@MIL-88A&PCL was placed in a glass petri dish containing 200 g of soil, which was subsequently placed outdoors (Number of samples per test ≥ 3. Rainfall was present during the test. Test dates: 2024.08.04-08.14; 9.07-9.17; 09.20-09.30. Location: Nankai University, Tianjin, China). The morphological change of the samples at different degradation times was recorded. Undegraded samples were collected from the soil using a 35-standard mesh screen. The collected samples were excessively washed with deionized water and dried under vacuum. The weight of undegraded samples was measured.

Soil toxicity test

The potting experiments were as follows: 500 g of soil from the experimental group contained 2 g of FM-10@MIL-88A&PCL degradation product, and the soil from the blank group was left untreated. The soil was filled into square plastic pots (45 cm × 31 cm × 16 cm), followed by the addition of 24 corn seeds (depth: 3 cm) and 300 mL of water per pot. The plastic pots were placed outdoors after the corn germinated, and 200 mL of distilled water was added daily. After two weeks, the corn plants were examined for wet weight, dry weight, height, root length, and chlorophyll content. The experiment was repeated three times for each group. P < 0.01 was statistically significant.

Statistics and reproducibility

No statistical methods were used to predetermine sample size. No data were excluded from the analyses. The experiments were not randomized. The investigators were not blinded to allocation during experiments and outcome assessments. Statistical significance between two groups was determined by a two-sided, unpaired Student’s t-test, unless otherwise noted in the figure legends. All experiments were performed at least three times with similar results.

Reporting summary

Further information on research design is available in the Nature Portfolio Reporting Summary linked to this article.

Supplementary information

Supplementary Information (3.7MB, pdf)
Reporting Summary (2.4MB, pdf)
Transparent Peer Review file (1.5MB, pdf)

Source data

Source Data (5.1MB, xlsx)

Acknowledgements

The authors acknowledge the financial support from the National Natural Science Foundation of China (22578462 and 22371136), the European Research Council (ADG 885695), Haihe Laboratory of Synthetic Biology (22HHSWSS00008), and the Autonomous Deployment Project of State Key Laboratory of Biopharmaceutical Preparation and Delivery (grant no. 2024ZZ-03, 2024-SJK-01, and 2024-FX-A-04).

Author contributions

Y.C. initiated and directed the project; J.C. performed the major experiments, X.G. performed cellular experiments, 3D printing experiments, and degradation experiments; J.Y. participated in CLSM and LC-MS testing, M.J. and W.D. provided the critical enzymatic reagents (LCC and HiC), S.W. participated in plant growth experiments, C.J. assisted in the preparation of composite membrane materials and testing of their mechanical properties; Y.C., Z.Z., M.Z., X.G. H.H., and J.C. wrote the paper, and all authors contributed to revising the paper.

Peer review

Peer review information

Nature Communications thanks Fenghuan Wang and the other anonymous reviewers for their contribution to the peer review of this work. [A peer review file is available.]

Data availability

All data generated or analysed during this study are included in this published article (and its supplementary information files). Source data are provided with this paper.

Competing interests

The authors declare no competing interests.

Footnotes

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Contributor Information

He Huang, Email: huangh@njnu.edu.cn.

Michael J. Zaworotko, Email: michael.zaworotko@ul.ie

Yao Chen, Email: chenyao@nankai.edu.cn.

Supplementary information

The online version contains supplementary material available at 10.1038/s41467-026-72354-3.

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Supplementary Information (3.7MB, pdf)
Reporting Summary (2.4MB, pdf)
Transparent Peer Review file (1.5MB, pdf)
Source Data (5.1MB, xlsx)

Data Availability Statement

All data generated or analysed during this study are included in this published article (and its supplementary information files). Source data are provided with this paper.

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