Made available in DSpace on 2014-06-11T19:30:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-20Bitstream added on 2014-06-13T19:00:05Z : No. of bitstreams: 1 medeiros_jb_me_araiq.pdf: 3851893 bytes, checksum: ca39fa9d9a3d6332fa80515bbbc4edf6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A área de biocatálise está em franco desenvolvimento e fungos associados a espécies vegetais dos biomas brasileiros são biocatalisadores em potencial, praticamente inexplorados. Nesse contexto, o presente trabalho descreve a avaliação do potencial biocatalítico de 7 fungos endófitos isolados de espécies vegetais do Cerrado. Foi avaliada a capacidade dos micro-organismos Nigrospora sphaerica, Schizophyllum commune, Phomopsis sp., Tricoderma viridae, Aspergillus versicolor, Xylaria sp. e Phomopsis stipata biotransformarem ou biodegradarem os substratos ácido gálico e cassina. O estudo de tolerância dos micro-organismos aos substratos permitiu selecionar as concentrações nas quais o ácido gálico (1,0 g L-1) e a cassina (0,5 g L-1) foram adicionados ao meio reacional na etapa de biotransformação/biodegradação. Todos os micro-organismos estudados se mostraram capazes de biotransformar o substrato ácido gálico. Os 26 produtos biotransformados são mais apolares que o composto de partida e foram encontrados na fase aquosa ou no micélio microbiano. Em relação à cassina, os endófitos Schizophyllum commune, Tricoderma viridae e Xylaria sp. não a metabolizaram, mesmo após 14 dias de incubação.Os endófitos Nigrospora sphaerica e Aspergillus versicolor a biodegradaram, enquanto que Phomopsis stipata e Phomopsis sp. a biotransformaram em 6 e 3 novos compostos, respectivamente. Os produtos de biotransformação do ácido gálico e da cassina terão suas estruturas determinadas em trabalhos futuros, e a partir desses dados poderemos inferir as reações que os fungos são capazes de realizar, e consequentemente sugerir as atividades enzimáticas presentes nos fungos endófitos estudados / The area of biocatalysis is developing fast and fungi associated with plant species of Brazilian biomes are potential biocatalysts, virtually unexplored. In this context, this work describes the evaluation of biocatalytic potential of seven fungal endophytes isolated from species of the Cerrado. We evaluated the ability of the micro-organisms Nigrospora sphaerica, Schizophyllum commune, Phomopsis sp., Tricoderma viridae, Aspergillus versicolor, Xylaria sp. and Phomopsis stipata to biotransform or biodegrade the substrates gallic acid and cassine. The study of microorganisms tolerance to the substrate allowed to select the concentrations in which the gallic acid (1.0 g L-1) and cassine (0.5 g L-1) were added to the reaction medium in step biotransformation/ biodegradation. All microorganisms studied are quite capable of biotransform substrate gallic acid. The 26 biotransformed products are less polar than the starting compound and were found in the aqueous phase or microbial mycelium. In relation to the cassine, the endophytes Schizophyllum commune, Tricoderma viridae and Xylaria sp. didn´t metabolize it, even after 14 days of incubation. Endophytes Nigrospora sphaerica and Aspergillus versicolor biodegraded the cassine, while Phomopsis stipata and Phomopsis sp. biotransformed this substrat in six and three new compounds, respectively. The biotransformation products of gallic acid and cassine will have their structures determined in future studies, allowing to infer which biotransformations occurred, and therefore suggest which the enzyme activities are found in the fungal endophyte studied

Made available in DSpace on 2014-10-09T12:38:17Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:29Z (GMT). No. of bitstreams: 1 05661.pdf: 7886710 bytes, checksum: 01bc6c86dc7ee9a79099061dadc6f84a (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Os compostos BTEX (benzeno, tolueno, etilbenzeno e xilenos) são os contaminantes mais frequentemente encontrados dentre os hidrocarbonetos de petróleo. A remoção destes compostos é dependente da atividade de uma população de micro-organismos adaptados capazes de promover a biodegradação dos mesmos. Neste estudo, foram utilizadas cinco cepas isoladas de área contaminada capazes de degradar estes compostos. As concentrações de BTEX foram determinadas por análises quantitativas realizadas por cromatografia gasosa com extração por headspace. Uma série de experimentos foi realizada para investigar a capacidade destas cepas de remover os compostos BTEX de forma individual e simultânea. Os ensaios de indução de vias metabólicas mostraram que cada um dos BTEX foi capaz de induzir as vias de degradação de todos os quatro substratos, resultado que foi visualizado a partir do crescimento das cepas em cada um dos BTEX após as mesmas terem sido ambientadas em apenas um deles. Para os ensaios de degradação, Os resultados revelaram que as cinco cepas foram capazes de degradar todos os BTEX, tanto na forma de um único substrato bem como em forma de mistura. As taxas de remoção de um único substrato ficaram entre 63,9% e 97,9%. Houve um aumento da degradação dos compostos quando os mesmo foram fornecidos em forma de mistura. Com exceção do benzeno, todos os compostos foram degradados até atingirem concentrações que ficaram abaixo do limite de potabilidade estipulados, dentro de 9 horas. / BTEX (benzene, toluene, ethylbenzene and xylenes) compounds are the most frequently encountered subsurface contaminants among the various petroleum hydrocarbons. Removal of these compounds is dependent on the activity of a population of microorganisms adapted to promote biodegradation of them. In this study, five strains isolated from contaminated groundwater .able to degrade BTEX compounds were used. BTEX concentrations were determined by quantitative analysis performed by gaseous chromatography with headspace extraction. A series of batch experiments were carried out to investigate the ability of the strains for removing BTEX compounds using single and mixed substrates. The pathway induction assays showed that each one of the BTEX compounds was able to induce the degradation pathways of all four substrates, result that was visualized from the growth of the strains in each of the BTEX after they had been set in only one of them. For the degradation assays, the results revealed that the five strains were able to degrade all BTEX, both in the form of a single substrate as well as in the form of a mixture. The rates of removal of a single substrate were between 63.9% and 97.9%. There was an increased degradation of the compounds when they were provided as a mixture. With the exception of benzene, all compounds were degraded to concentrations below the stipulated drinking limit within 9 hours.

Orientador: Anita Jocelyne Marsaioli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-25T12:48:43Z (GMT). No. of bitstreams: 1 Angolini_CelioFernandoFigueiredo_D.pdf: 5315143 bytes, checksum: 8dd92777c4d60094caaa95a789eb6ae2 (MD5) Previous issue date: 2014 / Resumo: Neste trabalho avaliou-se a ação de micro-organismos em amostras de petróleo naturalmente biodegradadas e em ensaios de biodegradação realizados em laboratório, através da otimização de um protocolo que utiliza metodologias rápidas de análise da fração polar por ESI-MS. Assim sendo foi possível aferir a composição molecular dos constituintes das classes de compostos oxigenados (O, O2, O3 e O4) e nitrogenados (N, NO, NO2, NO3) presentes no petróleo e correlacioná-las ao fenômeno de biodegradação, e ambiente deposicional em óleos da Bacia de Campo e da Bacia Potiguar, respectivamente. As informações geradas nesse estudo contribuíram para o entendimento da origem dos biomarcadores ácidos através da degradação dos respectivos hidrocarbonetos. Complementando o escopo principal do trabalho foram caracterizados dos micro-organismos do petróleo por técnicas de espectrometria de massas, mostrando a importância do desenvolvimento desta técnica com construções de bibliotecas de referência e elaboração de softwares mais elaborados. Finalizando foi realizada a síntese de um biomarcador trideuterado com ampla utilização em estudos de petróleo / Abstract: In this work we were able to evaluate the action of microorganisms in naturally biodegraded samples and in biodegraded laboratory assays, by optimizing a protocol that uses fast methods of analysis of the polar fraction by ESI-MS. Which was possible to determine the molecular composition of the compounds for oxygen (O, O2, O3 and O4) and nitrogen classes (N, NO, NO2, NO3) present in petroleum. Allowing to correlate those classes with the biodegradation phenomenon, and the depositional environment for the different studied petroleum samples. Even more information is generated about the origin of biomarkers acids through degradation of the respective hydrocarbons. In addition to the main scope of work, we characterize the petroleum microorganisms by mass spectrometry techniques, showing the importance of developing this MO identification technique by the construction of reference libraries and development of more sophisticated software. Also we synthesized a trideuterated biomarker widely used in studies with petroleum / Doutorado / Quimica Organica / Doutor em Ciências

The biological degradation of lignocellulose into fermentable sugars for the production of liquid transportation fuels is feasible and sustainable, but equires a variety of enzymes working in synergy as lignocellulose is a complex and recalcitrant substrate. The cellulosome is a multi-enzyme complex (MEC) with a variety of cellulolytic and hemicellulolytic enzymes that appears to facilitate an enhanced synergy and efficiency, as compared to free enzymes, for the degradation of recalcitrant substrates such as lignocellulose and plant cell walls. Most of the studies on cellulosomes have focused on a few organisms; C. thermocellum, C. cellulovorans and C. cellulolyticum, and there is only limited knowledge vailable on similar complexes in other organisms. Some MECs have been identified in aerobic bacteria such as Bacillus circulans and Paenibacillus curdlanolyticus, but the nature of these MECs have not been fully elucidated. This study investigated the cellulolytic and emi-cellulolytic system of Bacillus licheniformis SVD1 with specific reference to the presence of a MEC, which has never been reported in the literature for B. licheniformis. A MEC of approximately 2,000 kDa in size, based on size exclusion chromatography using Sepharose 4B, was purified from a culture of B. licheniformis. When investigating the presence of enzyme activity in the total crude fraction as well as the MEC of a birchwood xylan culture, B. licheniformis was found to display a variety of enzyme activities on a range of substrates, although xylanases were by far the predominant enzyme activity present in both the crude and MEC fractions. Based on zymogram analysis there were three CMCases, seven xylanases, three mannanases and two pectinases in the crude fraction, while the MEC had two CMCases, seven xylanases, two mannanases and one pectinase. The pectinases in the crude could be identified as a pectin methyl esterase and a lyase, while the methyl esterase was absent in the MEC. Seventeen protein species could be detected in the MEC but only nine of these displayed activity on the substrates tested. The possible presence of a β-xylosidase in the crude fraction was deduced from thin layer chromatography (TLC) which demonstrated the production of xylose by the crude fraction. It was furthermore established that B. licheniformis SVD1 was able to regulate levels of enzyme expression based on the substrate the organism was cultured on. It was found that complexed xylanase activity had a pH optimum of between pH 6.0 and 7.0 and a temperature optimum of 55oC. Complexed xylanase activity was found to be slightly inhibited by CaCl2 and inhibited to a greater extent by EDTA. Complexed xylanase activity was further shown to be activated in the presence of xylose and xylobiose, both compounds which are products of enzymatic degradation. Ethanol was found to inhibit complexed xylanase activity. The kinetic parameters for complexed xylanase activity were measured and the Km value was calculated as 2.84 mg/ml while the maximal velocity (Vmax) was calculated as 0.146 U (μmol/min/ml). Binding studies, transmission electron microscopy (TEM) and a bioinformatic analysis was conducted to investigate whether the MEC in B. licheniformis SVD1 was a putative cellulosome. The MEC was found to be unable to bind to Avicel, but was able to bind to insoluble birchwood xylan, indicating the absence of a CBM3a domain common to cellulosomal scaffoldin proteins. TEM micrographs revealed the presence of cell surface structures on cells of B. licheniformis SVD1 cultured on cellobiose and birchwood xylan. However, it could not be established whether these cell surface structures could be ascribed to the presence of the MECs on the cell surface. Bioinformatic analysis was conducted on the available genome sequence of a different strain of B. licheniformis, namely DSM 13 and ATCC 14580. No sequence homology was found with cohesin and dockerin sequences from various cellulosomal species, indicating that these strains most likely do not encode for a cellulosome. This study described and characterised a MEC that was a functional enzyme complex and did not appear to be a mere aggregation of proteins. It displayed a variety of hemi-cellulolytic activities and the available evidence suggests that it is not a cellulosome, but should rather be termed a xylanosome. Further investigation should be carried out to determine the structural basis of this MEC.

Aflatoxins are highly carcinogenic secondary metabolites that can contaminate approximately 25% of crops and that cause or exacerbate multiple adverse health conditions, especially in Sub-Saharan Africa and South and Southeast Asia. Regulation and decontamination of aflatoxins in high exposure areas is lacking. Biological detoxification methods are promising because they are assumed to be cheaper and more environmentally friendly compared to chemical alternatives. White-rot fungi produce non-specific enzymes that are known to degrade aflatoxin in in situ and ex situ experiments. The aims of this study were to (1) decontaminate aflatoxin-B-1-(AFB(1)) in naturally contaminated maize with the edible, white-rot fungus Pleurotus ostreatus (oyster mushroom) using a solid-state fermentation system that followed standard cultivation techniques, and to (2) and to assess the risk of mutagenicity in the resulting breakdown products and mushrooms. Vegetative growth and yield characteristics of P. ostreatus were not inhibited by the presence of-AFB(1).-AFB(1) was degraded by up to 94% by the Blue strain. No aflatoxin could be detected in P. ostreatus mushrooms produced from-AFB(1)-contaminated maize. Moreover, the mutagenicity of breakdown products from the maize substrate, and reversion of breakdown products to the parent compound, were minimal. These results suggest that P. ostreatus significantly degrades-AFB(1) in naturally contaminated maize under standard cultivation techniques to levels that are acceptable for some livestock fodder, and that using P. ostreatus to bioconvert crops into mushrooms can reduce-AFB(1)-related losses.

M.Sc. (Chemistry) / Please refer to full text to view abstract

Plastic are a highly durable, lightweight and low cost family of polymeric materials that form an essential and integral component of today’s world. Their continued world-wide large scale manufacture has led them to be a major component of man-made waste. A large proportion of plastic waste is directed to the landfill sites, however their low degradation rates, scarcity of landfill sites and growing water and land pollution problems require alternatives to be developed. Composting is a natural process involving aerobic decomposition of organic wastes by a mixed microbial consortium that involves thermophilic microbes during the process due to the heat generated during decomposition. In this study we investigated the biodegradation of polyurethane under composting conditions. Polyurethanes are heteropolymers with a wide range of applications in the medical, automotive, construction and domestic field and in Europe account for 7% of all plastic manufacture and have been shown to be susceptible to biodegradation, particularly by fungi. In this thesis, it was found that loss in tensile strength of >70% occurs at both mesophilic (25°C) and thermophilic (45° and 50°C) temperatures under laboratory conditions and so is susceptible to degradation at all stages of the composting process. Moreover, polyester PU buried in compost piles at a commercial composting site during the maturation phase of an in silo composting process also underwent substantial degradation. Non-culture based analysis by TRFLP, DGGE and 454 pyrosequencing revealed that the fungal communities colonising the surface of PU was substantially different from the surrounding compost indicating selection of fungi on the PU surface. Pyrosequencing revealed that under laboratory conditions, at 25°C Fusarium solani, and 45°C and 50°C, Candida ethanolica was the dominant organism recovered from the PU surface, whereas at the commercial composting site an unidentified fungal clone and Arthrographis kalrae were the dominant organisms recovered. When the microparticulate polyester PU dispersion impranil was added to compost, a substantial shift in the indigenous fungal population was observed along with an increase in fungal viable numbers, however, addition of larger solid PU had no lasting effect on the surrounding compost community. This study demonstrates that polyester PU is highly susceptible to degradation in during composting and indicates a future potential for directing PU wastes to existing commercial composting processes.

The development of a "cradle-to-cradle" mindset with both material performance during utilization and end of life disposal is a critical need for both ecological and economic considerations. The main limitation to the use of the biopolymers is their mechanical properties. Reinforcements are therefore a good alternative but disposal concerns then arise. Thus the objective of this dissertation is to investigate a biopolymer nanocomposite where the filler is a synthetically prepared layer double hydroxide (inorganic interface); and a biopolymer paper (organic interface) based coating or laminate. The underlying issues driving performance are the packing density of the biopolymer and the interaction with the reinforcement. Since the polyhydroxyalkanoates or PHAs (the biopolymers used for the manufacture of the nanocomposites and coatings) are semicrystalline materials, the glass transition was investigated using dynamic mechanical analysis (DMA) and dielectric spectroscopy (DES), whereas the melt crystallization, cold crystallization and melting points were investigated using differential scanning calorimetry (DSC). Fourier transform infrared (FTIR) spectroscopy was used to estimate crystallinity in the coated material given the low thermal mass of the PHA in the PHA coating. The significant enhancement of the crystallization rate in the PHA nanocomposite was probed using DSC and polarized optical microscopy (POM) and analyzed using Avrami and Lauritzen-Hoffman models. Both composites showed a significant improvement in the mechanical performance obtained by DMA, tensile and impact testing. The degradation and decomposition of the two composites were investigated in low microbial activity soil for the cellulose paper (to slow down the degradation rate that occurs in compost) and in compost. An in-house system according to the American Society for Testing and Materials ASTM D-98 (2003) was engineered. Soil decomposition showed that PHA coating into and onto the cellulose paper can be considered to be a useful method for the assessment of the degradability of the biopolymer. PHA nanocomposite showed enhanced compostability.

M. Tech (Department of Chemistry, Faculty of Applied and Computer Sciences) Vaal University of Technology. / Water is a limited resource and pollution has become an increasing problem due to industrialization. Aromatic organic pollutants are resistant to biodegradation, and thus chemical methods like the Fenton reaction is required for degradation. The Fenton reaction is catalyzed by cobalt oxide. This study aims to investigate the effect of size and shape of cobalt oxide nanoparticles on the catalytic activity. Methylene blue (MB) was used as a model pollutant. The size and shape of nanoparticles are known to influence the activity of catalysts. The study used a precipitation method to prepare spherical and cubic-shaped cobalt oxide nanoparticles of different sizes using preparation parameters like cobalt precursor, amount and type of oxidant and time of reaction. The XRD patterns of all the prepared cobalt oxide nanoparticles showed a pure cubic Co3O4 phase. The shape of the nanoparticles changed from spherical to cubic when the cobalt precursor was changed from cobalt nitrate to cobalt acetate. The size of the nanoparticles increased when lower amounts of hydrogen peroxide and longer reaction times were used. Nanoparticles between 4.6 to 19.5 nm for spherical particles and between 6.6 and 43.3 nm for cubic particles were prepared. FTIR spectra analysis showed the presence of both nitrate and acetate ions on the surface of cobalt oxide nanoparticles. The TGA results indicated that the adsorption of the acetate ions is stronger than the nitrate ions on the surface of the cobalt oxide nanoparticles. The rate of degradation of methylene blue, the pseudo first order rate constant and the amount of leaching increased with a decrease in the nanoparticles size. The Turn Over Frequency (TOF), which is the moles of methylene blue converted per mole of surface cobalt atoms, decreased with a decrease in the size for both the spherical and cubic nanoparticles. The TOF for the spherical and cubic nanoparticles were similar indicating that the catalytic activity may not be dependent on the shape of the nanoparticles. FTIR analyses showed that degradation occurred, and that methylene blue was not just decolourised to leuco methylene blue.