1,395 research outputs found
Nano-Ecotoxicology of Natural and Engineered Nanomaterials for Microorganisms
No full textThe mobility of nanomaterials (NMs) varies according to their surface charges, polarity and the media properties they come into contact. When compared to bulk materials their degradability is lower and solubility is slower. These two facts result in longer bioavailability periods and increased possibility of transport to further distances. In general terms, all of NMs produce toxic effects in living organisms, again depending on the interaction with the surrounding media. Given the possibility of enhanced transport, it could be assumed that soon or later NMs will reach environmental conditions that trigger their toxic effects to the local biota. The physiological pathway they trigger is linked to the cellular production of Reactive Oxygen Species (ROS), which would further result in reduction of cellular growth and even cell death, depending on the concentrations of NMs and the sensibility of the given organism. NMs’ toxicity and transport can vary with 1) time (due to changes suffered once in the environment), 2) space (due to seasonal or other fluctuations in environmental features), and 3) the species. Therefore, a general protocol for NMs testing should be developed. In general, such a general protocol should use NMs and their aged derivates for determination of toxicity in at least three local species of different trophic levels under different conditions (e.g., temperature, light, or environmental conditions such as different dissolved organic matters, aerobic or anaerobic settings) (Blaise et al. 2008). There are a large number of standardized bioassays that can be also used for evaluating NMs toxicity. All of them use different medium conditions and different target organisms, which can produce significantly different results.This chapter focuses on nano-ecotoxicology of natural and engineering NMs for microorganisms. The chapter starts with mobility, bioavailability and degradability of NMs in the environment, and then moves into general considerations of toxicity and eco-toxicity of NMs, followed by discussions about the comet and the micronucleus assays, including the K micronuclei and Ames tests and Highthroughput screening and current status in the related areas.Fil: Cledón, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Brar, Satinder Kaur. No especifíca;Fil: Zhang, Tian C. No especifíca
An Overview on Fate, Transport, and Behavior of Nanomaterials in the Environment
No full textThis chapter presents an overview of the fate, transport, and behavior of nanomaterials (NMs) in the environment, explaining that most releases of manufactured NMs or engineered NMs originate from point or nonpoint sources. A few well-known properties are likely to be helpful in predicting the transport and separation among environmental media based on past research on contaminants (e.g., PCBs). The chapter provides examples of known chemical properties of nanoparticles in different environmental media. It then represents NM transformation in the environment with respect to NM release into air and its reaction and deposition, which leads to toxicity. NM transformation in other environment compartments may occur differently. Finally, the chapter discusses some cases of bioaccumulation in different types of organisms and overviews the current state of knowledge in this field.Fil: Shahare, Manju B.. Université du Québec a Montreal; CanadáFil: Chaabouni, Emna. Université du Québec a Montreal; CanadáFil: Negandhi, Karita. Université du Québec a Montreal; CanadáFil: Brar, Satinder Kaur. Institut national de la recherche scientifique; CanadáFil: Tyagi, Rajeshwar. Institut national de la recherche scientifique; CanadáFil: Surampalli, Rao. Global Institute for Energy, Environment and Sustainability; Estados UnidosFil: Laurion, Isabelle. Université du Québec a Montreal; CanadáFil: Zhang, Tian. Universidad de Nebraska - Lincoln; Estados UnidosFil: Cledón, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin
Biopolymers Synthesis and Application
No full textLiving organisms, namely, prokaryotes and eukaryotes, are able to synthesize a variety of polymers, such as nucleic acids, proteins, and other polyamides, polysaccharides, polyesters, polythioesters, polyanhydrides, polyisoprenoids, and lignin. Microorganisms provide a source of biopolymers and biopolysaccharides from renewable sources. Bacteria are capable of yielding biopolymers with properties comparable to plastics derived from petrochemicals, though more expensive. They have the additional advantage of being biodegradable. A wide range of microbial polysaccharides have been studied, and structure/function relationships for a number of these macromolecules have been determined. These biopolymers accomplish different essential and beneficial functions for the organisms. Among the biopolymers produced, many are used for various industrial applications. Currently, the biotechnological production of polymers has been mostly achieved by fermentation of microorganisms in stirred bioreactors. The biopolymers can be obtained as extracellular or intracellular compounds. Alternatively, biopolymers can also be produced by in vitro enzymatic processes. However, the largest amounts of biopolymers are still extracted from plant and animal sources. Biopolymers exhibit fascinating properties and play a major role in the food processing industry, e.g., modifying texture and other properties. Among the various biopolymers, polysaccharides and bioplastics are the most important in the food industry. This chapter will discuss the sources of polymers, their biosynthesis by different organisms, and their application in different fields
C3–C4 Platform Chemicals Bioproduction Using Biomass
No full textPlatform chemicals composed of 3–4 carbons are group of chemicals that can be used as important precursors for making a variety of chemicals and materials, including solvents, fuels, polymers, pharmaceuticals, perfumes, and foods. At present, most of the commercial platform chemicals composed of 3–4 carbons are produced from petroleum-based products. However, fossil-derived resources are nonrenewable and their amount is increasingly depleting. Additionally, application of these materials has number of environmental concerns. To overcome these problems, increasing interest has focused on the development of sustainable technologies for producing these platform chemicals from renewable resources. Researchers have made significant progress in biological production using metabolic of platform chemicals using engineering-modified microorganisms. However, the production efficiency still needs to be improved for it to become economically viable. Further work on engineering these strains and exploring their tolerances and the use of low-cost renewable substrate like biomass may increase the yields of green platform chemicals to an industrial scale. In this review we focused on the current status of the bio-based production of major C3–C4 platform chemicals, by direct microbial bioconversion of renewable materials
Utilization of Agro-industrial Waste for the Production of Aroma Compounds and Fragrances
No full textAgro-industrial wastes are unavoidable waste materials continuously generated in bulk quantity. Most of these materials can be used as nutrient source for industrial fermentation. However, commercial fermentation of low-value high-volume products generally suffer financial crisis. Alternatively, sustainable biotransformation of agro-industrial waste into fine biochemical, such as aroma compounds and fragrances, has been widely investigated. Significant variation of substrate quality imparts great variations in the production methodology of these processes. Further, a range of microorganisms are known to be used and different genetic engineering strategies have been applied for improved bioconversion. Moreover, novel strategies for detection, identification, and purification of the final products have been developed, and in some particular cases, successful commercialization has also been achieved. To have, however, further benefit from this potential strategy, a systematic study of the type and nature of the feedstock and their abundance should be evaluated. Similarly, presently used processes and their scale-up potential should be determined and different options for their economic competitiveness should be identified. The goal of this chapter, therefore, is to improve the basic understanding of the interesting strategy and to summarize the recent advancements in production of aroma compounds and fragrances
Antioxidants
No full textAntioxidants are a class of chemical substances naturally found in our food which can prevent or reduce the oxidative stress of the physiological system. The body is constantly producing free radicals due to regular use of oxygen. These free radicals are responsible for the cell damage in the body and contribute to various kinds of health problems, such as heart disease, diabetes, macular degeneration, and cancer. Antioxidants being fantastic free radical scavengers help in preventing and repairing the cell damage caused by these radicals
Waste Biomass: A Prospective Renewable Resource for Development of Bio-Based Economy/Processes
No full textAlthough industrial revolution is an important factor governing the development of a country’s economy, but at the same time, the industrial activities have been also accompanied by problem of waste biomass. This commensurate with the increase in industrialization, urbanization, and population growth is leading to production of enormous quantities of industrial waste biomass that may cause environmental and health hazards. However, the increased awareness and desire for a healthy environment among people leads to the need for better ways of waste minimization and pollution prevention and better use of resources in achieving the required industrial and environmental standards. The present book deals specifically with the valorization of waste biomass to small-volume high-value biochemicals only. The products which are produced in bulk quantities, such as biofuels, some organic acids, hydrolytic enzymes, biogas, and other traditional products from waste biomass, are not discussed. In this context, the current chapter discusses the different sources, types, and nature of waste biomass. The chapter also provides overview of the different management strategies applied for the value addition of different types of waste biomass. The chapter will provide insights into the role of waste biomass resources for developing bio-based economy/processes for industrial biotechnology and renewable energy in supporting sustainable development and economic competitiveness
Intertechnique comparisons for nanoparticle size measurements and shape distribution
Get PDFThere are a number of techniques for measuring and characterization of nanoparticle (NP) size. One of the main problems in the field of NP analysis is in producing reliable and reproducible characterization data for nanomaterials (NMs). There is no one technique or method that is best suited for every situation, therefore the chosen methodologies improve results from a given sample matrix to produce the needed information in the shortest time and most cost-efficient way. A straightforward monitoring method may simply detect the presence of NMs; others may quantify the size distribution, surface area, or the number of the NPs. The interest in the development of wastewater treatment procedures is growing, therefore several clean-up technologies are being proposed in wastewater treatment that apply NMs as nanosorbents and photocatalysts. This review briefly introduces and compares the fundamental principles of routinely used NP size distribution measurements using both single particle (electron and scanning probe microscopy) and particle population methods, such as dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and small angle X-ray scattering (SAXS) and outlines the latest applications of NMs, such as nano Ag, TiO2, ZnO, and iron oxide in wastewater treatment and gaps hindering their large-scale use. The outlook for potential applications as well as further challenges is discussed. Currently, DLS is not suitable for analysis of manufactured silver nanoparticles (AgNPs) in environmental samples, whereas the faster and easier to start with is NTA for TiO2 and ZnO nanomaterials in liquid matrices. Finally, an intercomparison of results between methods shows how different measurements are interpreted to give consistent results.Fil: Amini, Ramin. Université du Québec a Montreal; CanadáFil: Brar, Satinder Kaur. Université du Québec a Montreal; CanadáFil: Cledón, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Surampalli, Rao Y.. Universidad de Nebraska - Lincoln; Estados Unido
A computational fluid dynamics approach to predict the scale-up dimension of a water filter column
Get PDFA bench-scale filter consisting of sand media was tested for hydrodynamic parameters (velocity and pressure) using ANSYS-CFX (computational fluid dynamics or CFD software) to further determine the ‘subjective minimum scale-up’ (SMS) filter dimension. The purpose of this study is to relate the hydrodynamics property of the bench scale column and the scale-up column for a porous fluid flow using CFD to understand the scale-up limitations. The poor flow regime in bench-scale filter was observed because of a high variance in the pressure gradient as obtained for a plane perpendicular to the direction of fluid flow (orthogonal plane). The flow regime pattern was analyzed by structural modelling and in-built programming using the concept of CFD. Using CFD, a SMS filter dimension was obtained that was found free of high-pressure gradient (on orthogonal plane near the column exit) that might have incurred due to a ‘bad’ flow regime in case of the bench-scale filter. This could sort operational issues caused due to pressure-velocity parameters and would help researchers to step-up with scale-up dimension (from bench-scale) more confidently and credibly. The simulation was obtained for the scale-up reactor using the intrinsic properties to validate the model. An error of 4.1% was reported between the experimental velocity of the bench-scale filter vs simulated value from ANSYS-CFX. Also, a better plug flow condition was obtained for the scale-up column using CFD (Morill dispersion index or MDI = 3) as compared to that of bench-scale filter (MDI = 2.2).Fil: Kumar, Pratik. Indian Institute Of Technology; IndiaFil: Brar, Satinder Kaur. University of York; Reino Unido. Université du Québec a Montreal; CanadáFil: Cledón, Maximiliano. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; Argentin
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