Capítulos de libros

Permanent URI for this collection

https://repositorio.uc.cl/handle/11534/22991

Browse

Browsing Capítulos de libros by browse.metadata.categoriaods "06 Agua limpia y saneamiento"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    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.
  • No Thumbnail Available
    Item
    Regulation and Protection of Urban Wetlands: A Comparative Analysis in Chile, Colombia, and Peru
    (Springer, 2024) Moschella, Paola; Rojas Quezada, Carolina Alejandra; Aldana-Domínguez, Juanita; Stamm, Caroline Andre; Velásquez, Carlos Javier; Capera, Ingrid
    Latin American countries have a set of legal instruments and public policies that contribute to the protection of urban wetlands against the pressure of city expansion that threatens their extent and quality. With the aim of discussing the role of public policies and regulations in the protection of urban wetlands, the situation in Chile, Colombia, and Peru is analyzed in a comparative manner. These countries are examples of diverse regulations and wetland biodiversity in urban environments. Legal instruments for environmental protection and conservation, spatial planning, and urban planning relevant to the management of urban wetlands are analyzed. In addition, advances in regulation and protection of urban wetlands are evaluated and contrasted based on national-level indicators. The lack of effective protection measures is demonstrated. The three countries have adhered to the Ramsar Convention to protect their wetlands and have established Ramsar sites; however, their existence does not stop the pressures and threats to the wetlands. It is identified that Peru has a larger surface area of Ramsar sites and that Colombia has the most extensive Ramsar urban wetland. It is highlighted that Chile has a recent urban wetlands law, while in Colombia and Peru the category of urban wetland does not exist in legislation. Meanwhile, in the protected natural areas, urban wetlands practically have no presence. Among the main weaknesses are the disarticulation between sectors and planning scales; in addition to outdated planning instruments regarding current challenges such as climate change, the water crisis, and the loss of biodiversity.
  • No Thumbnail Available
    Item
    Urban Wetland Losses and Land-Use Conservation Challenges in Three Latin American Cities
    (Springer, 2024) Aldana-Domínguez, Juanita; Rojas Quezada, Carolina Alejandra; Munizaga, Juan; Moschella, Paola; Stamm, Caroline Andre; Martínez, Carolina
    Wetlands are valuable and threatened ecosystems throughout the world. They are essential for the maintenance of life and ecological balance, in addition to providing a larger number of benefits to human societies. Wetlands reduce the risk of flooding by regulating the flow of water, being essential to reduce the impacts of climate change, especially along the coasts and coastal cities of the world. Urban growth poses a risk to wetlands in and around urban areas. In this work, we quantify the loss trends of wetlands in urban areas in three Latin American countries between the years 2002 and 2019. We selected as case studies the wetlands of Aconcagua in Chile, Ciénaga de Mallorquín in Colombia, and Pantanos de Villa in Peru. Through multitemporal analysis of Quickbird satellite imagery collections, we classify land covers at 2.5-m resolution and identify areas covered by wetland. We quantify the losses and gains of the wetland areas and the areas surrounding them. We found that the three wetlands analyzed lost area, confirming the worldwide trend of loss. The Ciénaga de Mallorquín wetland was the one that decreased the most due to coastal dynamics and urbanization. The Pantanos de Villa wetland reduced its area due to the increase in urban areas that grew filling the wetland under the pressure of informal settlements and beach condominiums. Lastly, the Aconcagua wetland was reduced due to the increase in grasslands together with the increase in bare soil, also affecting the beaches and dunes. In all three case studies, urban wetlands decreased due to urban growth. For this reason, we call attention to the urgency of improving urban planning to ensure the maintenance of these key ecosystems to ensure more sustainable and resilient cities, as proposed by Sustainable Development Goal 11.