Aug 2026· Journal of Hazardous Materials· Vol 515, pp.
143252
· 0 citations· 48 references
Medicine
TL;DR
A theoretical basis for using substrate pre-activation and evolved biocatalysis to treat PET-contaminated alkaline industrial effluents is provided, providing a theoretical basis for using substrate pre-activation and evolved biocatalysis to treat PET-contaminated alkaline industrial effluents.
Abstract
Polyethylene terephthalate (PET) is a hazardous environmental contaminant that contributes to both plastic and microplastic pollution, with its biodegradation severely limited by the kinetic stability of ester bonds-particularly in alkaline industrial wastewater (pH 9-11) where most known biocatalysts are inactive. To overcome this, evolutionary engineering was employed to construct a whole-cell biocatalyst for alkaline environments. Through UV-LiCl mutagenesis and adaptive laboratory evolution, an alkaline-adapted Comamonas testosteroni strain F6 was developed, thriving at pH 10 with PET as sole carbon source. Strain F6 increased weight loss from 2.4% to 6.1% in 3 days and accelerated terephthalic acid release versus the wild-type under neutral conditions. This improvement arises from a synergistic mechanism: alkaline conditions chemically pre-activate ester bonds, and the released monomers fuel microbial growth and enzyme secretion, establishing a self-reinforcing degradation cycle. This feedback-driven process caused severe surface erosion, reducing fiber diameter from 20.2 to 18.1 μm. The system operates at mild pH 10 and 37 °C with a self-moderating effect that partially neutralizes alkalinity, contrasting with harsh chemical hydrolysis (pH >13, high temperature). This work provides a theoretical basis for using substrate pre-activation and evolved biocatalysis to treat PET-contaminated alkaline industrial effluents.
Integrating thermolabile enzymes into industrial melt processing remains a key challenge for achieving programmable self-degradable plastics. Here, we demonstrate a process-compatible stabilization strategy for bio-based polyesters using immobilized Alcalase. Two approaches were compared: adsorption onto zeolite (Z-En) and entrapment within a citric acid–crosslinked carboxymethyl cellulose matrix (C-En-CA). Poly(lactic acid) (PLA) masterbatches containing 10 wt% C-En-CA retained catalytic functionality after twin-screw extrusion at temperatures up to 210 °C. Hydrolytic testing in 0.05 M Tris–HCl buffer (pH 8.0) resulted in a 10.03% mass loss after 3 weeks, confirming enzyme survival following melt compounding. When incorporated into PBAT T-die films, the C-En-CA system achieved 79.5% biodegradation within 45 days under industrial composting conditions. These results demonstrate that appropriate immobilization enables enzymatic stabilization under realistic extrusion temperatures, offering a scalable pathway toward controllable end-of-life degradation in commercially relevant biodegradable plastics. Ultimately, this study establishes a new paradigm for polymer–enzyme composites by overcoming the long-standing 200 °C thermal barrier, effectively unlocking the practical deployment of biocatalytic masterbatches in industrial manufacturing.
J. Seo, In-Woo Nam, Hyojung Kim et al.· Polymers· 0 citations
Polybutylene adipate terephthalate (PBAT) is prone to incomplete degradation, leading to environmental pollution and carbon resource waste. Biodegradation and valorization of waste plastics are essential for addressing plastic pollution and promoting a circular economy. Enzymatic degradation offers advantages, but free enzymes suffer from low stability and poor recyclability. Here, surface display technology was used to construct a cutinase Tfcut-DM display system in Escherichia coli BL21(DE3). The results showed that surface display significantly enhanced the stability and reusability of Tfcut-DM. Compared with free enzymes, its thermostability and pH stability increased by 11.9-fold and 42.1-fold, respectively, and approximately 80% of initial activity was retained after seven reuse cycles. Under optimized conditions, the surface-displayed strain released 255.9 µM of terephthalic acid (TPA) from PBAT films over 5 days, with near-complete degradation. To enable TPA valorization , the tph operon was introduced to C. necator H16 (CnH16-tph) for TPA-to-PHB conversion. A co-culture system comprising the surface-displayed strain and CnH16-tph was established for proof-of-concept one-pot conversion of PBAT to PHB. PHB accumulation is indirectly attributed to the TPA derived from PBAT degradation. Under optimized conditions, the maximum PHB yield reached 0.91 g/L. While isotopic tracing would be required for definitive carbon flux assignment, this indirect evidence strongly suggests the successful conversion of PBAT-derived TPA to PHB. This study provides a novel approach for the green degradation and resource utilization of waste PBAT, facilitating the recycling of discarded resources.
Jiali Liu, Jie Yang, Xin Wang et al.· Bioresource Technology· 0 citations
Herein, a highly rigid monomer, 2-(2-hydroxyethyl)-1,3-dioxoisoindoline-5-carboxylic acid (HTI), was readily prepared from biosourced malic acid. A series of PET copolyesters were fabricated through an in situ chemical upcycling strategy, in which HTI units were inserted into the backbones of the PET waste via a depolymerization-repolycondensation process. The resulting copolyesters demonstrated outstanding thermal stability (T5% > 400 °C) and excellent optical transparency, with transmittance at 700 nm ranging from 86.8% to 90.6%. Incorporation of HTI units significantly improved the glass transition temperature and mechanical property of PET; notably, the copolyester containing 41 mol % HTI exhibited a tensile strength of 62.8 MPa and a Young’s modulus of 1.66 GPa. Furthermore, these PET copolyesters underwent complete methanolysis at 160 °C, enabling closed-loop recycling of the initial monomers in high yields. This work provides a new strategy for upcycling PET waste using biobased monomers, which incentivize both improved thermal-resistance, mechanical properties, and plastics reclamation.
In the context of a bio-based circular economy, replacing fossil raw materials with renewable alternatives has become a major trend. Platform chemicals such as itaconic acid and 2.5-furandicarboxylic acid can now be produced from sugars or lignocellulose and used to synthesize fully bio-based polyesters e.g. poly(ethylene 2.5-furandicarboxylate) with thermomechanical and barrier properties comparable to conventional polyesters. Life cycle assessments indicate that these bio-based polymers emit significantly less greenhouse gas than their fossil-derived counterparts, and thermomechanical testing and degradation studies confirm their practical suitability. Current crosslinking methods typically rely on melamine and isocyanates, which pose toxicological and ecological disadvantages. We propose using itaconic acid as a renewable crosslinking component to address these issues, with the crosslinking reaction tailored through catalyst selection. In our work, the incorporation of itaconic units into the polyester was confirmed by SEC (size-exclusion chromatography),
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H-NMR (nuclear magnetic resonance spectroscopy), ATR-FTIR (attenuated total reflectance-Fourier-transform infrared spectroscopy) analysis. Thermal/mechanical properties were characterized by DSC (differential scanning calorimetry) and DMTA (dynamic mechanical analysis). In situ ATR-FTIR and rheology reveal that network formation proceeds via two competing mechanisms: radical C–C crosslinking and oxa-Michael (C–O–C) addition. Catalyst choice dictates the dominant pathway. Brønsted acids (DBSA, MSA) reduce the apparent reaction order to ~ 0.6, whereas a radical initiator (di-tert-butyl peroxide, DTBP) enhances radical crosslinking (apparent order ~ 1.7). In contrast, Lewis acids and metal salts (e.g. AlCl
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, Zn(OAc)
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) suppress covalent gelation, favouring coordinative and supramolecular interactions over permanent covalent crosslinks. In coating tests, selected itaconate-containing formulations achieved an optimal balance of hardness, adhesion (crosscut = 0), and solvent resistance, with pendulum hardness values reaching 94–105 when catalyzed by MSA (methanesulfonic acid)/DBSA (dodecylbenzene sulfonate)/DTBP. These results demonstrate that the network architecture and thus the functional properties of itaconic acid–based renewable polyester coatings can be precisely controlled through targeted selection of catalysts and matrices. This approach offers a promising strategy for developing sustainable, high-performance bio-based coating materials.
Daniel Sandvoß, J. S. Gutmann, M. Dornbusch· Journal of Coatings Technolo...· 0 citations
Abstract In this study, a hybrid biocatalyst was developed via rapid in-situ biomineralization of laccase within a cobalt(II)-malonate framework (Lac@MOF). The novelty lies in using malonic acid as a biocompatible linker, enabling rapid enzyme encapsulation under mild conditions. Structural integrity was confirmed through SEM, TGA, EDS, and XPS analyses. Lac@MOF exhibited expanded operational pH and temperature ranges. A notable enhancement in catalytic activity (∼150%) was observed at elevated temperatures, suggesting that the framework stabilizes the enzyme’s active conformation against thermal denaturation. The hybrid material achieved ∼66% Bisphenol A (BPA) removal within 240 min and retained 60% of its initial activity after seven reuse cycles. These findings demonstrate that the Co-malonate framework effectively enhances laccase stability and reusability. The developed biocomposite offers a cost-effective and robust strategy for industrial scale-up, providing a promising platform for the efficient biocatalytic treatment of endocrine-disrupting micro-pollutants in environmental remediation.
Biocatalytic ester synthesis often encounters bottlenecks like vast substrate polarity differences and reliance on toxic solvents or activated acyl donors, severely limiting industrial expansion. To address this, a novel catalytic deep eutectic solvent (CDES) system composed of cyclohexanone, stearic acid, and N-methylimidazole (CS-NMI) was developed. This study utilized an extreme esterification, sucrose stearate synthesis, as a model reaction due to the immense substrate sizes and polarity differences. After optimization, the conversion for sucrose stearate synthesis reached 98.2± 0.7%, remaining at 90.5± 0.8% even after 10 reuses of the lipase. More crucially, enzymatic esterification of sucrose with inexpensive stearic acid was achieved, yielding 42.8± 0.5% conversion. To verify the system's broad applicability, the synthesis of vitamin E succinate, menthyl acetate, and propyl laurate were performed, all achieving yields over 85.0% without optimization. To further expand the enzymatic universality and industrial application potential of CS-NMI, an in-house Candida antarctica lipase B (CALB) mutant, X1, was employed to synthesize sucrose stearate in CS-NMI. Following scale-up in a 5 L fermenter (achieving a fermentation enzyme activity of 6.7± 1.9 U/mL without concentration) and kilogram-scale immobilization, this non-commercial enzyme X1 attained a remarkable 98.1± 1.3% conversion for sucrose stearate synthesis. Molecular dynamics (MD) simulations indicated that CS-NMI maintained the enzyme's dynamic conformation, reconstructed the hydrophobic microenvironment of the binding pocket, and enhanced mass transfer within the tunnel. Overall, the highly adaptable solvent-enzyme-substrate synergistic system constructed in this study provides a sustainable and universal strategy for complex biocatalytic esterification.
