Magnetic silica-coated cutinase immobilized via ELPs biomimetic mineralization for efficient nano-PET degradation.

The proliferation of nano-plastic particles (NPs) poses severe environmental hazards, urgently requiring effective biodegradation methods. Herein, a novel method was developed for degrading nano-PET (polyethylene terephthalate) using immobilized cutinases. Nano-PET particles were prepared using a straightforward method, and biocompatible elastin-like polypeptide-magnetic nanoparticles (ELPs-MNPs) were obtained as magnetic cores via biomimetic mineralization. Using one-pot synthesis with the cost-effective precursor tetraethoxysilane (TEOS), silica-coated magnetically immobilized ELPs-tagged cutinase (ET-C@SiO2@MNPs) were produced. ET-C@SiO2@MNPs showed rapid magnetic separation within 30 s, simplifying recovery and reuse. ET-C@SiO2@MNPs retained 86 % of their initial activity after 11 cycles and exhibited superior hydrolytic capabilities for nano-PET, producing 0.515 mM TPA after 2 h of hydrolysis, which was 96.6 % that of free enzymes. Leveraging ELPs biomimetic mineralization, this approach offers a sustainable and eco-friendly solution for PET-nanoplastic degradation, highlighting the potential of ET-C@SiO2@MNPs in effective nanoplastic waste management and contributing to environmental protection and sustainable development.

An antifouling epoxy coated metal surface containing silica-immobilized carbonic anhydrase supraparticles for CO2 capture through microalgae.

Carbonic anhydrase (CA) has a promising application as a green and efficient biocatalyst for CO2 capture, and many successful cases of immobilizing CA have been reported. However, CA antifouling coatings on metal for CO2 sequestration have rarely been reported. Herein, dimeric CA from Sulfurihydrogenibium azorense (SazCA) with a ferritin tag, which was prepared by low-speed centrifugation with high yield, was adopted as a free enzyme and encapsulated in the sol-gel silica. The silica-immobilized CAs were dispersed into the commercialized metal-antifouling epoxy resin paint to obtain CA coated nickel foams, which had excellent stability, with 90 % and 67 % residual activity after 28 days of incubation at 30 °C and 60 °C, respectively. The CA coated nickel foams remained 60 % original activity after 6 cycles of use within 28 days. Then, a CA-microalgae carbon capture device was constructed using the CA coated nickel foams and Chlorella. The growth rate of Chlorella was significantly increased and the biomass of Chlorella increased by 29 % compared with control after 7 days of incubation. Due to the simple and cost-effective preparation process, sustainable and efficient CO2 absorption, this easy-to-scale up CA coated nickel foam has great potential in CA assisted microalgae-based CO2 capture and carbon neutrality.

A versatile tag for simple preparation of cutinase towards enhanced biodegradation of polyethylene terephthalate.

Enzymatic degradation of polyethylene terephthalate (PET) suffered from challenges such as complex and costly enzyme preparation, difficult access to PET substrates, poor reusability of free enzymes and sometimes MHET inhibitions. Herein, we propose an "all-in-one" strategy to address these issues with a well-designed elastin-like polypeptides (ELPs) tag. The preparation of the ELPs-tagged cutinase (ET-C) was efficient and easy to scale up by centrifugation, with an activity recovery of 57.55 % and a yield of 160 mg/L. Besides, the activity of the ET-C was 1.3 and 1.66-fold higher in degrading PET micro- and macro-plastics compared to wild-type cutinase. The self-immobilized cutinase (ET-C@SiO2) obtained by the ELPs-mediated biosilicification exhibited high loading capacity, activity, and thermostability and maintained 77.65 % of the original activity after 10 reuses. Interestingly, the product of the ET-C was TPA, whereas the wild-type was TPA and MHET. This is a simple way to release the intermediates inhibition compared with the existing methods. Our results demonstrated the feasibility of the versatile ELPs tag, which will pave an alternative economic way for scalable PET biodegradation.