199 resultados para Biodegradação


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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In this study nanocomposites of PLA and organoclays Cloisite 20A and Cloisite 30B were prepared by melt intercalation. The influence from the organoclays on the biodegradation of PLA was evaluated based on the respirometry method. The incorporation of clay Cloisite 20A did not change the mineralization curve of PLA. The nanocomposite with Cloisite 30B, on the other hand, presented a different behavior, indicating a delay in the polymer biodegradation. The materials were characterized by X-ray Diffraction, Thermogravimetric Analysis and Differential Scanning Calorimetry. The materials characterization indicated nanocomposites with an intercalated structure as well as reduced thermal stability and a slight increase in the degree of crystallinity compared to the pure polymer.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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This work intends to investigate the biodegradation of the polymers and blend films of polypropylene (PP) and poly(hidroxybutirate-valerate) (PHBV), after UV radiation to facilitate the PP degradation, which is a polymer with long chains difficult to degrade by biological agents present in the environment. This polymer is outstanding by its mechanical properties and versatility of industrial and commercial use and the PHBV by its quick biodegradability in the environment. Blends of these materials could to present a commitment between mechanical properties and biodegradability to execute its function and after the discard to have lesser lifetime in the garbage landfills. Another aspect of this work is the controlling effect of PP on PHBV, influencing its degradation time

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The State of São Paulo is responsible for the largest sugar cane production in Brazil, as well as the largest production of ethanol made of this raw material – which is widely used as fuel for automobiles. This utilization began in the 1970’s, with the institution by the Brazilian government of the National Alcohol Program (PRO-ÁLCOOL), as a consequence of the petroleum crisis, rising again five years ago, with the development of flex fuel cars. The obtaining process of ethanol originates residues; amongst them, vinasse is the one that’s generated in the largest amount (an average of 10 to 13 litres/litre of ethanol produced). The disposal of this residue in waters was only forbidden in 1978, but before that, researchers had already been investigating its utilization as raw material. This paper had the objective of accompany the biodegradation of vinasse by evaluating the oxygen comsumption during it until the ultimate Biochemical Oxygen Demand (uBOD), performed in twenty days; another objective was to analyse the biomass production of Saccharomyces cerevisae in this residue. Physical and chemical analyses of the residue were also performed, as well as acute toxicity essays using Daphnia similis and Dugesia tigrina, before and after its biodegradation. The physical and chemical analyses pointed elevated acidness (pH = 3,98), conductivity (8,30 mS/cm) and COD (25.693,43 mg O2/L) and mean quantity of suspended solids (5.246 mg/L). The toxicity essays indicated absence of toxic potential in vinasse after biodegradation for both species. The uBOD degradated until 88,22% of the COD, demonstrating the possibility of biodegradation of most of the residue’s organic load in a relatively short period of time. S. cerevisae caused a 37,03% COD diminution in vinasse, diminished its conductivity and promoted a slight elevation of the pH; it obtained low biomass...(Complete abstract click electronic access below)

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The use of polymeric materials has grown in recent years due to its high durability features, atoxicity, shaping versatility and environment resistance. However, while these features represent good advantages to several industry sectors, it results in one of the most serious environmental problems of contemporary society: the rising accumulation of these material, mainly due to the inadequate disposal of waste. Meanwhile, in order to minimize this problem, some mitigation techniques comes up (arises), among which the use of biodegradable polymers has been gaining attention. Because of their easily action of microorganisms, such material degrade more rapidly, becoming integrated to nature. Furthermore, due to the fact of biodegradation is a natural process, occurring through the action if micro-organisms in the environment itself, it is considered the “cleaner” alternative found so far to plastic components reincorporation in the nature. Among the micro-organisms capable of biodegradation process are the filamentous fungi. These micro-organisms have many advantages over the others, the major one being the capacity to produce a range of enzymes capable of degrading different materials. In this context, the present review made it possible to see the importance of this process as an agent of environmental preservation, suggest the use of blends to minimize the problems of cost and flexibility of biodegradable polymeric materials, as well as noting the lack of studies related to this subject nowadays

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A grande quantidade de resíduos plásticos sintéticos descartada diariamente no meio ambiente tem preocupado governantes do mundo todo. No sentido de minimizar este problema várias soluções estão sendo propostas. Uma delas é a busca de materiais potencialmente biodegradáveis no solo. Neste trabalho desenvolveu-se blendas de poli(3-hidroxibutirato) PHB, um polímero biodegradável, com polietileno de baixa densidade PEBD, um polímero convencional e avaliou-se os efeitos do termotratamento em estufa e do fototratamento em câmara de envelhecimento acelerado sobre a biodegradação destes filmes em coluna de solo. As blendas de PEBD/PHB foram preparadas em composições de 90/10, 80/20 e 70/30, utilizando prensa sob aquecimento e os filmes foram analisados por Espectroscopia de Absorção no Infravermelho (FTIR), Microscopia de Luz Polarizada (MLP), perda de massa e ângulo de contato.

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The oil and biodiesel are oily substances which, if spilled or thrown out in the environment, can cause serious damages. In this context, bioremediation techniques can be used to the recovering of sites degradated by mineral or vegetable oil, besides them, the biodegradation. However, it is necessary that there are microorganism strains used to degradate the contaminant, previously selected for the fast, efficient and minimum impact remediation. The main objective of this study was to isolate microorganism strains coming from different ecological recesses and verify their potentiality on biodegradating oil and biodiesel. Strains of bacteria, fungi and yeasts were isolated from soils contaminated by hydrocarbons (diesel, gasoline, grease) before, by doing striations on culture plates. On the biodegradation tests, it was used the redox indicator, 2,6-dichlorophenol indophenol (DCPIP), then, after the indicador’s discoloration, the absorbance of the suspension obtained was measured. 46 different microorganism strains were isolated, and the oil, when it was used as a carbon resource, it was degradate easier than the biodiesel. The experiments showed that, in a period, the site impacted by oil spills recovers itself by the biodegradation, in aerobic conditions, by the redox activity.

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Polímeros são macromoléculas de alta massa molecular cada vez mais presentes nas atividades humanas. Estas moléculas são utilizadas com frequência para sintetizar plásticos, elastômeros e fibras. Os polímeros podem ser divididos em naturais e sintéticos. Os polímeros de origem natural são aqueles encontrados na natureza, como por exemplo: celulose, hemicelulose, glicogênio, proteínas, amido, lignina, entre outros. Os polímeros sintéticos são aqueles produzidos pela síntese química induzida pelo ser humano, como os diferentes tipos de plásticos. Contudo, alguns destes materiais sintéticos possuem alta durabilidade acarretando grande acúmulo de resíduos que contaminam o meio ambiente. O poliacrilato de sódio (PAS) é uma destas moléculas sintéticas que funciona como superabsorvente utilizado em grande escala nas fraldas descartáveis. A aplicação do PAS nas fraldas permitiu diminuir o volume deste material sem perda da eficácia. Cerca de 136 milhões de quilos de polímeros de poliacrilato são utilizados anualmente. Buscando diminuir a quantidade deste material no meio ambiente, são necessários estudos que viabilizem alternativas de sua decomposição. Dentre as opções viáveis está o processo de biodegradação, que é caracterizado pela ação de seres vivos, sobretudo os pertencentes ao grupo dos microrganismos (bactérias e fungos), que utilizam o material para retirar a energia para o seu desenvolvimento. Este projeto tem como objetivo avaliar a biodegradabilidade do poliacrilato de sódio (PAS) e modificar sua estrutura via degradação microbiana. Análises descritivas e comparativas são as bases para o estudo e compreensão da biodegradação do PAS. Para os testes de biodegradação serão utilizados microrganismos do solo e o fungo Aspergillus niger. Após 8 meses de biodegradação do composto enterrado pôde-se concluir através... (Resumo completo, clicar acesso eletrônico abaixo)