Capítulos de libros

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Browsing Capítulos de libros by Subject "06 Clean water and sanitation"

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    Enhancement of Peroxidase Stability Against Oxidative Self-Inactivation by Co-immobilization with a Redox-Active Protein in Mesoporous Silicon and Silica Microparticles
    (2016) Sahare, P.; Osorio Román, Igor; Ayala, M.; Vazquez-Duhalt, R.; Pal, U.; Loni, A.; Canham, L. T.; Agarwal, V.
    Abstract The study of the stability enhancement of a peroxidase immobilized onto mesoporous silicon/silica microparticles is presented. Peroxidases tend to get inactivated in the presence of hydrogen peroxide, their essential co-substrate, following an auto-inactivation mechanism. In order to minimize this inactivation, a second protein was co-immobilized to act as an electron acceptor and thus increase the stability against self-oxidation of peroxidase. Two heme proteins were immobilized into the microparticles: a fungal commercial peroxidase and cytochrome c from equine heart. Two types of biocatalysts were prepared: one with only covalently immobilized peroxidase (one-protein system) and another based on covalent co-immobilization of peroxidase and cytochrome c (two-protein system), both immobilized by using carbodiimide chemistry. The amount of immobilized protein was estimated spectrophotometrically, and the characterization of the biocatalyst support matrix was performed using Brunauer–Emmett–Teller (BET), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared (FTIR) analyses. Stability studies show that co-immobilization with the two-protein system enhances the oxidative stability of peroxidase almost four times with respect to the one-protein system. Thermal stability analysis shows that the immobilization of peroxidase in derivatized porous silicon microparticles does not protect the protein from thermal denaturation, whereas biogenic silica microparticles confer significant thermal stabilization.Abstract The study of the stability enhancement of a peroxidase immobilized onto mesoporous silicon/silica microparticles is presented. Peroxidases tend to get inactivated in the presence of hydrogen peroxide, their essential co-substrate, following an auto-inactivation mechanism. In order to minimize this inactivation, a second protein was co-immobilized to act as an electron acceptor and thus increase the stability against self-oxidation of peroxidase. Two heme proteins were immobilized into the microparticles: a fungal commercial peroxidase and cytochrome c from equine heart. Two types of biocatalysts were prepared: one with only covalently immobilized peroxidase (one-protein system) and another based on covalent co-immobilization of peroxidase and cytochrome c (two-protein system), both immobilized by using carbodiimide chemistry. The amount of immobilized protein was estimated spectrophotometrically, and the characterization of the biocatalyst support matrix was performed using Brunauer–Emmett–Teller (BET), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and Fourier transform infrared (FTIR) analyses. Stability studies show that co-immobilization with the two-protein system enhances the oxidative stability of peroxidase almost four times with respect to the one-protein system. Thermal stability analysis shows that the immobilization of peroxidase in derivatized porous silicon microparticles does not protect the protein from thermal denaturation, whereas biogenic silica microparticles confer significant thermal stabilization.
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    Nature-Based Solutions as Critical Urban Infrastructure for Water Resilience
    (Edward Elgar Publishing, 2023) McPhillips, Lauren; Wu, Hong; Rojas Quezada, Carolina Alejandra; Rosenzweig, Bernice; Sauer, Jason R.; Winfrey, Brandon
    Nature-based solutions (NBS) are key for managing water resources, as well as providing many other benefits. While traditionally “gray” highly engineered strategies have been used to manage water in urban areas, we articulate the role that NBS can play in managing water related to flooding, drought, and water quality challenges. Specifically, NBS for water can range from hybrid ecological-technological features explicitly engineered to manage stormwater to other designed or intact natural features such as wetlands or parks that may provide water management as a co-benefit. Criteria are reviewed for choosing the best NBS for the intended goal(s), and we showcase several case examples of NBS for water resilience from around the world. Remaining knowledge gaps for NBS for water implementation include space challenges, changes in performance over time, and incorporation of NBS that are not explicitly engineered for water management into existing management and regulatory frameworks.