Chem & Bio Engineering最新文献

The worldwide accumulation of plastic waste in the environment, along with its lifespan of hundreds of years, represents a serious threat to ecosystems. Enzymatic recycling of plastic waste offers a promising solution, but the high chemical inertness and hydrophobicity of plastics pose several challenges to enzymes. In nature, lytic polysaccharide monooxygenases (LPMOs) can act at the surface of recalcitrant biopolymers, taking advantage of their solvent-exposed active sites and appended carbohydrate-binding modules (CBMs). LPMOs can disrupt the densely packed chains of polysaccharides (e.g., cellulose) by the oxidation of C–H bonds. Given the similarities between these natural and artificial polymers, we aimed here at promoting plastic-binding properties to LPMOs, by swapping their CBM with three natural, surface-active accessory modules displaying different amphipathic properties. The polymer binding capacity of the resulting LPMO chimeras was assessed on a library of synthetic polymers, including polyester, polyamide, and polyolefin substrates. We demonstrated that the plastic binding properties of these engineered LPMOs are polymer-dependent and can be tuned by playing on the nature of the accessory module and reaction conditions. Remarkably, we gained full binding for some chimera LPMOs with striking results for polyhydroxyalkanoates (PHA). In the long term perspective of harnessing the unique copper chemistry of LPMOs to degrade plastics, we also provided the first evidence of LPMO-dependent modification of the PHA polymer, as supported by enzyme assays, gel permeation chromatography, and scanning electron microscopy. Altogether, our study provides the first roadmap for engineering plastic-binding ability in LPMOs, constituting a crucial first step on the evolutionary path toward efficient interfacial catalysis of plastic-active enzymes.

The worldwide accumulation of plastic waste in the environment, along with its lifespan of hundreds of years, represents a serious threat to ecosystems. Enzymatic recycling of plastic waste offers a promising solution, but the high chemical inertness and hydrophobicity of plastics pose several challenges to enzymes. In nature, lytic polysaccharide monooxygenases (LPMOs) can act at the surface of recalcitrant biopolymers, taking advantage of their solvent-exposed active sites and appended carbohydrate-binding modules (CBMs). LPMOs can disrupt the densely packed chains of polysaccharides (e.g., cellulose) by the oxidation of C-H bonds. Given the similarities between these natural and artificial polymers, we aimed here at promoting plastic-binding properties to LPMOs, by swapping their CBM with three natural, surface-active accessory modules displaying different amphipathic properties. The polymer binding capacity of the resulting LPMO chimeras was assessed on a library of synthetic polymers, including polyester, polyamide, and polyolefin substrates. We demonstrated that the plastic binding properties of these engineered LPMOs are polymer-dependent and can be tuned by playing on the nature of the accessory module and reaction conditions. Remarkably, we gained full binding for some chimera LPMOs with striking results for polyhydroxyalkanoates (PHA). In the long term perspective of harnessing the unique copper chemistry of LPMOs to degrade plastics, we also provided the first evidence of LPMO-dependent modification of the PHA polymer, as supported by enzyme assays, gel permeation chromatography, and scanning electron microscopy. Altogether, our study provides the first roadmap for engineering plastic-binding ability in LPMOs, constituting a crucial first step on the evolutionary path toward efficient interfacial catalysis of plastic-active enzymes.

The liver's role in metabolism, detoxification, and immune regulation underscores the urgency of addressing liver diseases, which claim millions of lives annually. Due to donor shortages in liver transplantation, liver tissue engineering (LTE) offers a promising alternative. Hydrogels, with their biocompatibility and ability to mimic the liver's extracellular matrix (ECM), support cell survival and function in LTE. This review analyzes recent advances in hydrogel-based strategies for LTE, including decellularized liver tissue hydrogels, natural polymer-based hydrogels, and synthetic polymer-based hydrogels. These materials are ideal for in vitro cell culture and obtaining functional hepatocytes. Hydrogels' tunable properties facilitate creating artificial liver models, such as organoids, 3D bioprinting, and liver-on-a-chip technologies. These developments demonstrate hydrogels' versatility in advancing LTE's applications, including hepatotoxicity testing, liver tissue regeneration, and treating acute liver failure. This review highlights the transformative potential of hydrogels in LTE and their implications for future research and clinical practice.

The liver’s role in metabolism, detoxification, and immune regulation underscores the urgency of addressing liver diseases, which claim millions of lives annually. Due to donor shortages in liver transplantation, liver tissue engineering (LTE) offers a promising alternative. Hydrogels, with their biocompatibility and ability to mimic the liver’s extracellular matrix (ECM), support cell survival and function in LTE. This review analyzes recent advances in hydrogel-based strategies for LTE, including decellularized liver tissue hydrogels, natural polymer-based hydrogels, and synthetic polymer-based hydrogels. These materials are ideal for in vitro cell culture and obtaining functional hepatocytes. Hydrogels’ tunable properties facilitate creating artificial liver models, such as organoids, 3D bioprinting, and liver-on-a-chip technologies. These developments demonstrate hydrogels’ versatility in advancing LTE’s applications, including hepatotoxicity testing, liver tissue regeneration, and treating acute liver failure. This review highlights the transformative potential of hydrogels in LTE and their implications for future research and clinical practice.

Enhancing the performance of non-noble-metal catalysts would facilitate the economic feasibility of the chemical conversion process. Through strategies involving metal nanoparticles (MNPs) size control and support functionalization modification, Ni2Fe6/UiO-66-X-y catalysts (X stands for H, OH, CH₃, and NH₂, and y stands for the concentration of NaBH₄ solution) were prepared for the efficiently selective hydrogenation of methyl laurate (ML) to 1-dodecanol. High-concentration NaBH₄ solution facilitated the preparation of smaller-sized MNPs, while support functionalization could alter the chemical microenvironment of the support, thereby promoting electron transfer between appropriately sized MNPs and the support. In particular, the Ni2Fe6/UiO-66-NH₂-0.4 M catalyst could achieve 99.9% conversion of ML and 98.6% selectivity for 1-dodecanol when it was reacted at 220 °C and 3 MPa H₂ for 8 h. The probable catalytic mechanism based on the η²(C, O)-aldehyde conformation was discussed, and reaction kinetics were calculated. Furthermore, the catalyst achieved five stable recycling runs and demonstrated catalytic versatility for other fatty acid methyl esters, including methyl stearate, methyl palmitate, and methyl valerate.

Enhancing the performance of non-noble-metal catalysts would facilitate the economic feasibility of the chemical conversion process. Through strategies involving metal nanoparticles (MNPs) size control and support functionalization modification, Ni2Fe6/UiO-66-X-y catalysts (X stands for H, OH, CH₃, and NH₂, and y stands for the concentration of NaBH₄ solution) were prepared for the efficiently selective hydrogenation of methyl laurate (ML) to 1-dodecanol. High-concentration NaBH₄ solution facilitated the preparation of smaller-sized MNPs, while support functionalization could alter the chemical microenvironment of the support, thereby promoting electron transfer between appropriately sized MNPs and the support. In particular, the Ni2Fe6/UiO-66-NH₂-0.4 M catalyst could achieve 99.9% conversion of ML and 98.6% selectivity for 1-dodecanol when it was reacted at 220 °C and 3 MPa H₂ for 8 h. The probable catalytic mechanism based on the η²(C, O)-aldehyde conformation was discussed, and reaction kinetics were calculated. Furthermore, the catalyst achieved five stable recycling runs and demonstrated catalytic versatility for other fatty acid methyl esters, including methyl stearate, methyl palmitate, and methyl valerate.

With the increasing development of electric cars and portable electronic devices, the demand for advanced batteries with high energy density, long cycling lifespan, and enhanced safety is growing rapidly. In closed battery systems, a number of complex dynamic behaviors occur during cycling processes, such as chemical and structural changes of electrode particles, formation of solid electrolyte interphase (SEI), evolution of conducting electrode networks and distribution of electrolytes, all of which collectively impact the battery performance markedly. Conventional postcycling and bulk-level, ensemble-averaged electrochemical characterization techniques encounter challenges in establishing clear relationships between the micro/mesoscale structures of battery materials and the overall macroscopic device performance. In this review, we provide a timely overview of recent developments in operando imaging for multiscale characterization of batteries, spanning from sub/single-particle levels and interfaces to the electrode network and full battery levels. Operando imaging techniques shed light on the multiscale dynamic evolution mechanisms within closed battery systems, uncovering deeper understandings of the key factors that govern overall battery performance.

With the increasing development of electric cars and portable electronic devices, the demand for advanced batteries with high energy density, long cycling lifespan, and enhanced safety is growing rapidly. In closed battery systems, a number of complex dynamic behaviors occur during cycling processes, such as chemical and structural changes of electrode particles, formation of solid electrolyte interphase (SEI), evolution of conducting electrode networks and distribution of electrolytes, all of which collectively impact the battery performance markedly. Conventional postcycling and bulk-level, ensemble-averaged electrochemical characterization techniques encounter challenges in establishing clear relationships between the micro/mesoscale structures of battery materials and the overall macroscopic device performance. In this review, we provide a timely overview of recent developments in operando imaging for multiscale characterization of batteries, spanning from sub/single-particle levels and interfaces to the electrode network and full battery levels. Operando imaging techniques shed light on the multiscale dynamic evolution mechanisms within closed battery systems, uncovering deeper understandings of the key factors that govern overall battery performance.

The degradation and recycling of plastics, such as poly(ethylene terephthalate) (PET), often require energy-intensive processes with significant waste generation. Moreover, prevalent methods primarily entail physical recycling, yielding subpar materials. In contrast, upcycling involves breaking down polymers into monomers, generating valuable chemicals and materials for alternative products. Enzyme-catalyzed depolymerization presents a promising approach to break down PET without the need for extreme conditions and unstable or toxic metal catalysts, which are typical of traditional recycling methods. However, the practical application of enzymes has been hindered by their high cost and low stability. In this study, we stabilized the enzyme Humicola insolens cutinase (HiC) by encapsulating it within a mesoporous zirconium-based metal-organic framework, NU-1000. HiC@NU-1000 exhibited a quantitative degradation of the PET surrogate, ethylene glycol dibenzoate (EGDB), with greater selectivity than native HiC in producing the fully hydrolyzed product benzoic acid in partial organic solvent. Additionally, the heterogeneous catalyst is also active toward the hydrolysis of PET and has demonstrated recyclability for at least four catalytic cycles. The HiC@NU-1000 model system represents a promising approach to stabilize industrially relevant enzymes under conditions involving elevated temperatures and organic solvents, offering a potential solution for relevant protein-related applications.

The degradation and recycling of plastics, such as poly(ethylene terephthalate) (PET), often require energy-intensive processes with significant waste generation. Moreover, prevalent methods primarily entail physical recycling, yielding subpar materials. In contrast, upcycling involves breaking down polymers into monomers, generating valuable chemicals and materials for alternative products. Enzyme-catalyzed depolymerization presents a promising approach to break down PET without the need for extreme conditions and unstable or toxic metal catalysts, which are typical of traditional recycling methods. However, the practical application of enzymes has been hindered by their high cost and low stability. In this study, we stabilized the enzyme Humicola insolens cutinase (HiC) by encapsulating it within a mesoporous zirconium-based metal–organic framework, NU-1000. HiC@NU-1000 exhibited a quantitative degradation of the PET surrogate, ethylene glycol dibenzoate (EGDB), with greater selectivity than native HiC in producing the fully hydrolyzed product benzoic acid in partial organic solvent. Additionally, the heterogeneous catalyst is also active toward the hydrolysis of PET and has demonstrated recyclability for at least four catalytic cycles. The HiC@NU-1000 model system represents a promising approach to stabilize industrially relevant enzymes under conditions involving elevated temperatures and organic solvents, offering a potential solution for relevant protein-related applications.