Resumo: O desenvolvimento de novos materiais com fonte renovável, baixo custo, melhores propriedades físico-mecânicas e biodegradáveis tem se tornado o principal objetivo de muitas empresas e grupos de pesquisa. O principal objetivo deste trabalho foiestudare desenvolver materiais a partir de uma matriz de poliuretano (PU) derivada do óleo de mamona utilizando como reforço a fibra da celulose bacteriana (CB). O trabalho foi dividido em duas etapas, a primeira direcionada a escolher o melhor estado da fibra (úmida, seca ou liofilizada) e a melhor resina para a formação da matriz. Na segunda etapa, desenvolveram-se as condições de moldagem e compressão para a matriz e compósito. A formação dos compósitos na primeira etapa utilizou a fibra da CB em três estados diferentes, seca, úmida em pedaço, úmida triturada e liofilizada, e duas matrizes de resinas PU monocomponente com diferentes porcentagens de NCO livre para cada uma, na proporção de 80% de fibra CB e 20% da matriz PU. A partir dos resultados obtidos optouse por utilizar a fibra úmida e seca e a matriz para a moldagem foi desenvolvida como bicomponente, pois a monocomponente apresentou formação de bolhas devido à reação com a umidade e a presença de muito solvente. Na segunda etapa foram obtidos os compósitos com 10% de fibra seca com uma pequena porcentagem de água (7%) e 90% da matriz PU bicomponente. As condições de moldagem foram a 6 ton a 70ºC por 7h. Para a fibra úmida foi desenvolvido um processo de troca de solvente para diminuir a porcentagem de água com o objetivo de aumentar a interação com a matriz. Esse processo possibilita utilizar a fibra revestida com a resina em forma de tiras, fios ou manta como reforço na matriz PU ou em outras matrizes. A caracterização foi feita por Raio-X, Infravermelho, Termogravimetria, Calorimetria Exploratória Diferencial, Análise Dinâmico Mecânico e ensaios... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The development of new materials with renewable source, low cost, better physicsmechanical properties and biodegradable, has become the main objective of many companies and research groups. The main goal of this work was to study and to develop material from polyurethane matrix (PU) derivative from castor oil added to bacterial cellulose (BC) fiber as reinforcement. The present work was divided in two parts: first, a selection of adequate fiber (humid, dry or lyophilized) and adequate resin have been explored to prepare the matrix. In the second part, the conditions of molding and compression for the matrix and composite have been studied. The first stage of the composites were formed with different types of BC fiber, dry and humid like continuum, discontinue and lyophilized, the matrix used was PU monocomponent resin with different percentages of free NCO for each one, with the ratio 80% of BC fiber and 20% of PU matrix. From these results, it was possible to select the humid and dry fiber. The molding PU matrix was developed as bicomponent, because the monocomponent resin had several bubbles due to the high amount of solvent and reaction with humid. The second stage of the composites had 10% of dry fiber containing (7%) of water and 90% of bicomponent PU. The molding condition was 6 ton at 70ºC during 7h. To increase the interaction of the matrix and CB fiber, a process has been developed based on solvent exchange. The characterization was made by X-Ray Diffraction, Infrared, Thermogravimetry, Differential Scanning Calorimetry, Dynamic Mechanical Analysis and mechanical test of the tension and creep. The bicomponent matrix present viscoelastic properties and the reinforcement with BC enhanced some of the properties as: increases of the glass transition temperature; 5 times increment of elastic modulus, reduction of the storage module, low yield region and better behavior on creep. Therefore, these results are interesting and show that the dry. / Orientador: Younès Messaddeq / Coorientador: Wagner Luis Polito / Banca: Clóvis Augusto Ribeiro / Banca: Ana Maria de Guzzi Plépis / Mestre

An improved method to evaluate Young's modulus of bacterial cellulose (BC) nanofibrils is presented. This estimation takes into account polarisation configurations, nanofibril orientation and tensile deformation axis direction. A range of 79 - 88 GPa has been obtained showing their great potential to be used as reinforcement in composite materials. BC bio-composites, constituted of a BC layer embedded in-between two matrix layers, have been prepared by compression moulding. The stress-transfer from the matrix to the reinforcement has been quantified using Raman spectroscopy. This has been carried out by following the shift of the Raman band initially located at a wavenumber position of ~1095 cm-1. Polylactide (PLA) was chosen as matrix material due to its biodegradability and bio-sourced origin. Transparent polylactide films were obtained in specific processing conditions to suppress crystallisation. This allowed the laser to penetrate the matrix and interact with the upper layer of BC networks. Several factors that could affect the interface in these composites have been studied. The influence of the culturing time of BC networks on the composite interfaces has been investigated. Higher Raman band shift rates with respect to strain and stress have been measured for composites manufactured using BC networks having a low culturing time. This led to enhanced coupling between PLA and the upper layer of BC networks. Scanning electron microscopy imaging of the tensile fracture surface of these composites revealed that delamination between the BC layers was occurring rather than failure at the BC/PLA interface. Cross-linking of BC networks using glyoxal was performed to consolidate their layered structure. Raman spectroscopy was used to probe the stress-transfer of unmodified and cross-linked BC networks. These data revealed that cross-linked materials exhibit an enhanced stress-transfer both in the dry and wet states compared to unmodified BC networks. Cross-linked BC networks were used to design composites but no significant stress-transfer improvement was observed. As a result, maleated polylactide (MAPLA) was produced and used as a matrix material in order to consolidate the interface between PLA and both the upper and lower layer of cross-linked BC networks. Composites designed using cross-linked BC networks and MAPLA showed a significant stress-transfer improvement over composites designed using unmodified BC networks and PLA. Also the determination of the bulk tensile mechanical properties of the composites revealed a significant increase of relative Young's modulus. This increase is thought to be due to reduced molecular mobility at both the cross-linked BC/MAPLA interface and between cross-linked BC layers. This is further supported by scanning electron imaging of the tensile fracture surfaces.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21795号 / 工博第4612号 / 新制||工||1718(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 辻井 敬亘, 教授 山子 茂, 教授 渡辺 宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Electrokinetics is a family of effects that induces motion of a liquid or a particle within a liquid in response to an external electric field. Using the intrinsic electrical properties of bacteria and of breast cancer cells, electrokinetics can be used to manipulate these particles for two different types of applications: tissue engineering and breast cancer detection. The first application studied the effects of electric fields on bacteria cells as well as calcium ions to potentially create a meniscus scaffold with hydroxyapatite ends for anchoring. In response to the electric field, calcium ions were able to deposit locally and simultaneously with cellulose growth. Bacteria cells were also studied to determine their response under an AC field. At low frequencies, bacteria demonstrated controlled movement caused by electroosmosis and dielectrophoresis with a net motion caused by a dielectrophoretic force. In the second application, the separation capabilities of different stages of breast cancer cells from the same cell line were tested using contactless dielectrophoretic (cDEP) devices. The electric field gradients in cDEP devices were altered to optimize selectivity and to determine an estimated membrane capacitance for each. From the results, the membrane capacitance of the early to intermediate stages proved to be very similar; however, late stage breast cancer cells have potential in being separated from early and intermediate stages. / Master of Science

In strongly acidic soils (pH <4.5) aluminium (Al) becomes soluble in quantities that can lead to Al phytotoxicity. It is estimated that approximately 30 % of the worlds’ potentially arable lands are acidic, with Al toxicity the most limiting factor for plant growth on acid soils. With increasing use of marginal land in cropping systems, this area could reach 70 %. Cell wall pectin provides up to 70 % of the root cation exchange capacity. Pectin is suggested to control a number of physiological properties of the plant cell wall such as porosity, charge density, microfibril spacing and pH. The ability of pectin to bind cations is not only important for the uptake of nutrients but is implicated in metal toxicity, in particular Al. Despite over a century of research, the mechanisms of Al toxicity are yet to be fully elucidated or agreed upon. Gluconacetobacter xylinus is a gram-negative, soil dwelling bacterium which produces extracellular cellulose. It is an established archetype for the study of cellulose biogenesis. In the presence of pectin in the growth medium, the bacterium can form cellulose-pectin composites. Recently, the bacterium has been used to form composites as model cell walls to understand plant cell wall deposition. Additionally, bacterial cellulose composites in their natural hydrated state mimic the hydration state of primary plant cell walls. The aim of this project was to attempt to incorporate this novel cell wall analog into laboratory investigations into metal interactions with plant cell walls. Preliminary work was undertaken to optimise the bacterial culture medium, growth conditions, analysis of the composites and developing an overall general methodology. The medium buffering system was altered, growth under non-optimal pH conditions was evaluated and Al was successfully incorporated into the composites. Appropriate sample preparation for scanning electron microscopy (SEM) of the composites was determined. This work resulted in the successful production of bacterial cellulose-pectin composites with 30 % w/w pectin incorporation. The effect of Al on the tensile properties of the composites was examined. Aluminium had no effect on the stress/strain profiles, confirming the hypothesis that pectin is not the main load bearing component of the cell wall. The composites were used to investigate the effects of Al and other trace metals (copper (Cu), gadolinium (Gd), lanthanum (La), ruthenium (Ru) and scandium (Sc)) on the hydraulic conductivity of the composites. Hydraulic conductivity was reduced to ≈ 30 % of the initial flow rate by 39 μM Al and 0.6 Cu μM, ≈ 40 % by 4.6 μM La, 3 μM Sc and 4.4 μM Ru, and ≈ 55 % by 3.4 μM Gd. These metal concentrations were selected based on the concentrations causing a 50 % reduction in root elongation in cowpea (Vigna unguiculata L.). This study demonstrated that all the trace metals caused a similar decrease of hydraulic conductivity, despite the different concentrations of the metals used. Scanning electron microscopy showed changes in pectin porosity with metal binding which may account for the decreases in hydraulic conductivity observed. As the composites could not be used as a model material in all investigations, pectin-only systems were employed in a rheological study to investigate the effect of increasing concentrations of Al, Ca, Cu or La at pH 4 on pectin (degree of esterification 30 %, 1 % w/v) gel physical strength. Comparing similar saturation levels, La formed the weakest gel, followed by Ca, which was similar to Al, while the strength of Cu gels was almost an order of magnitude stronger than the other cations. This study was the first to investigate Al and La pectate gel strength. The swelling of the gels also varied, with Ca gels being the most swollen. Pectin was also used to determine the exchange selectivity of Al, Cu, Gd, La, Ru and Sc toward Ca pectate. The order of selectivity was found to be Sc>Gd>La>Cu>Ru>Al. There were some parallels between this sequence and the rhizotoxicity data of the metals, suggesting that the strength with which metals bind to pectin is an indication of their rhizotoxicity. Through the use of synthetic pectate gel systems new information was discovered about the strength of pectin gels and the selectivity of trace metals towards pectin. These findings were in keeping with those of a number of related studies, as well as with studies of plant root tissue. Overall, the novel bacterial cellulose-pectin cell wall analog was successfully integrated into research into Al and other metal toxicity in plants, and offers a useful system that can overcome some of the difficulties encountered when using plant cell wall tissue. Further research may be warranted on manipulating the growth system to produce composites in the presence of the metal (ie. metal added to the growth medium), as opposed to post-formation treatments. Moreover, the production of a three way composite of cellulose, hemicellulose and pectin would likely be another useful analog for plant cell wall material.

Orientador: Younés Messaddeq / Coorientador: Agnieszka Joanna Pawlicka Maule / Banca: Caio Eduardo de Campos Tambelli / Banca: Rogéria Rocha Gonçalves / Resumo: Esta dissertação apresenta a preparação e caracterização de membranas condutoras iônicas baseadas em celulose produzida pela bactéria Gluconacetobacter xylinus. Estas membranas foram preparadas a partir da imersão de membranas de celulose bacteriana (CB) em soluções aquosas de ácidos (ácido acético e ácido trifluoroacético) e/ou plastificantes (trietanolamina e glicerol). Estrutura e perfil térmico destas membranas condutoras foram investigados por difração de raios X (DRX), microscopia eletrônica de varredura (MEV), termogravimetria (TG), calorimetria exploratória diferencial (DSC), espectroscopia vibracional na região do infravermelho (FTIR) e espectroscopia de espalhamento Raman. As propriedades elétricas foram avaliadas utilizando-se espectroscopia de impedância eletroquímica (EIE). As análises de DRX mostram o aumento de plastificante diminui a cristalinidade das amostras, cujo recobrimento das microfibrilas pelo plastificante pode ser visualizado por análise de MEV, e os valores de condutividade iônica obtidos são maiores em comparação aos da CB seca. A condutividade na membrana é dependente do conteúdo de umidade e o plastificante age impedindo a desidratação da membrana. Foi observado também que combinações de ácido e plastificante resultaram em membranas com maiores condutividades do que aquelas em que houve apenas adição do plastificante, uma vez que a adição de ácidos pode aumentar a condutividade protônica / Abstract: This dissertation presents the preparation and characterization of ionic conducting membranes based on cellulose produced by bacteria Gluconacetobacter xylinus. These membranes have been prepared from bacterial cellulose membranes (BC) soaked in acids (acetic and trifluoroacetic acids) and/or plasticizer (triethanolamine and glycerol) aqueous solutions. The structure and thermal behavior of the conducting membranes were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), differential scanning calorymetry (DSC), infrared spectroscopy (FTIR) and Raman spectroscopy. Electrical properties were performed utilizing electrochemical impedance spectroscopy (EIS). From XRD analyses the amorphous phase becomes larger after increasing the amount of plasticizer that covers the cellulose microfibrils as revealed by SEM, and the obtained conductivity values were high in comparison to dried BC. The conductivity in the membrane is dependent on the moisture content and the plasticizer acts avoiding complete membrane dryness. It was also observed that the combination of acid and plasticizer resulted in membranes with higher ionic conductivity than plasticized ones, once the addition of acids may improve protonic conductivity / Mestre

Made available in DSpace on 2014-06-11T19:29:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2006Bitstream added on 2014-06-13T18:58:40Z : No. of bitstreams: 1 barud_hs_me_araiq.pdf: 4450763 bytes, checksum: 49a71a8b0b75c57b23a31bd5778f16f0 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A celulose bacteriana obtida pela cultura de Acetobacter xylinum apresenta alta massa molecular e alta cristalinidade quando comparada à celulose vegetal. Devido à auto-organização, microcristalinidade e estrutura tridimensional tem gerado um grande número de produtos comerciais. Eles incluem membranas para autofalantes e fones de ouvido, Biofill® (usado como pele artificial), fibras dietéticas (nata-de-coco), membranas para celas de combustível, e outros . Nesse trabalho, novos compósitos celulose/fosfato de sódio e celulose bacteriana/sílica foram preparados a partir de celulose bacteriana. Para os compósitos celulose/polifosfato de sódio, a difratometria de raios X apresentou contribuição das fases Ia e Iß da celulose e de fosfato recobrindo as fibras da estrutura da celulose. Alterações nas propriedades mecânicas e térmicas foram evidenciadas através das análises térmicas e mecânicas. Compósitos de celulose bacteriana e sílica foram preparados pela hidrólise de tetraetoxisilano (TEOS) na presença da celulose. Observou-se o depósito de nanopartículas de sílica sobre as microfibrilas de celulose. A presença de fase inorgânica contribui para a melhora das estabilidades térmicas e mecânicas da celulose bacteriana. / Bacterial cellulose obtained from cultures of Acetobacter xylinum presents higher molecular weight and higher crystallinity than plant cellulose. The selfassembled, microcrystalline and three dimensional network structures have lead to a number of commercial products. These include headphone membranes, paper, Biofill® (to be used as a temporary skin substitute), dietary fiber (nata-de-coco), fuel cells, and others 2. In this work, new composites based on bacterial cellulose/sodium phosphate and bacterial cellulose/silica were prepared. In the bacterial cellulose/polyphosphate composite DRX analyses presents Ia and Iß cellulose phases and adsorbed phosphate covering the cellulose microfibrils. Important changes in mechanical and thermal properties were evidenced for thermal and mechanics analyses. Composites on bacterial cellulose and silica were prepared from the hydrolysis/condensation of tetraethoxysilane (TEOS) on the cellulose microfibrils. The inorganic phase improves cellulose thermal stability and mechanical properties.

Made available in DSpace on 2014-06-11T19:29:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-07-10Bitstream added on 2014-06-13T19:58:52Z : No. of bitstreams: 1 pinto_erp_me_araiq.pdf: 5569467 bytes, checksum: 2f595227d3dc3f1b9f4455d7803afae6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O desenvolvimento de novos materiais com fonte renovável, baixo custo, melhores propriedades físico-mecânicas e biodegradáveis tem se tornado o principal objetivo de muitas empresas e grupos de pesquisa. O principal objetivo deste trabalho foiestudare desenvolver materiais a partir de uma matriz de poliuretano (PU) derivada do óleo de mamona utilizando como reforço a fibra da celulose bacteriana (CB). O trabalho foi dividido em duas etapas, a primeira direcionada a escolher o melhor estado da fibra (úmida, seca ou liofilizada) e a melhor resina para a formação da matriz. Na segunda etapa, desenvolveram-se as condições de moldagem e compressão para a matriz e compósito. A formação dos compósitos na primeira etapa utilizou a fibra da CB em três estados diferentes, seca, úmida em pedaço, úmida triturada e liofilizada, e duas matrizes de resinas PU monocomponente com diferentes porcentagens de NCO livre para cada uma, na proporção de 80% de fibra CB e 20% da matriz PU. A partir dos resultados obtidos optouse por utilizar a fibra úmida e seca e a matriz para a moldagem foi desenvolvida como bicomponente, pois a monocomponente apresentou formação de bolhas devido à reação com a umidade e a presença de muito solvente. Na segunda etapa foram obtidos os compósitos com 10% de fibra seca com uma pequena porcentagem de água (7%) e 90% da matriz PU bicomponente. As condições de moldagem foram a 6 ton a 70ºC por 7h. Para a fibra úmida foi desenvolvido um processo de troca de solvente para diminuir a porcentagem de água com o objetivo de aumentar a interação com a matriz. Esse processo possibilita utilizar a fibra revestida com a resina em forma de tiras, fios ou manta como reforço na matriz PU ou em outras matrizes. A caracterização foi feita por Raio-X, Infravermelho, Termogravimetria, Calorimetria Exploratória Diferencial, Análise Dinâmico Mecânico e ensaios... / The development of new materials with renewable source, low cost, better physicsmechanical properties and biodegradable, has become the main objective of many companies and research groups. The main goal of this work was to study and to develop material from polyurethane matrix (PU) derivative from castor oil added to bacterial cellulose (BC) fiber as reinforcement. The present work was divided in two parts: first, a selection of adequate fiber (humid, dry or lyophilized) and adequate resin have been explored to prepare the matrix. In the second part, the conditions of molding and compression for the matrix and composite have been studied. The first stage of the composites were formed with different types of BC fiber, dry and humid like continuum, discontinue and lyophilized, the matrix used was PU monocomponent resin with different percentages of free NCO for each one, with the ratio 80% of BC fiber and 20% of PU matrix. From these results, it was possible to select the humid and dry fiber. The molding PU matrix was developed as bicomponent, because the monocomponent resin had several bubbles due to the high amount of solvent and reaction with humid. The second stage of the composites had 10% of dry fiber containing (7%) of water and 90% of bicomponent PU. The molding condition was 6 ton at 70ºC during 7h. To increase the interaction of the matrix and CB fiber, a process has been developed based on solvent exchange. The characterization was made by X-Ray Diffraction, Infrared, Thermogravimetry, Differential Scanning Calorimetry, Dynamic Mechanical Analysis and mechanical test of the tension and creep. The bicomponent matrix present viscoelastic properties and the reinforcement with BC enhanced some of the properties as: increases of the glass transition temperature; 5 times increment of elastic modulus, reduction of the storage module, low yield region and better behavior on creep. Therefore, these results are interesting and show that the dry.

Made available in DSpace on 2017-07-21T20:43:45Z (GMT). No. of bitstreams: 1 Raysa Frankievicz.pdf: 2669303 bytes, checksum: 9e7cf92368c675d33a730546ebb1fccc (MD5) Previous issue date: 2014-08-13 / Due to environments problems caused by synthetic plastic, there is currently a search for replacing these materials with biodegradable materials. The study related to composites and nanocomposites formed from biodegradable materials and synthetic matrices has increased last years, and it has shown that these materials are very promising respect to biodegradation processes, besides presenting better properties than their pure components. In this work, it has been emphasized the production of nanofibers bacterial cellulose composite in a polypropylene matrix. The production of nanofibers from bacterial cellulose (BC) has been made in colloid mill. The material has been processed in a twin screw extruder in proportions of 1 %, 3% and 5% (w/w) of bacterial cellulose and coupling agent has been used as graphitized PP with maleic anhydride. The samples have been characterized by thermogravimetric analysis (TGA), x-ray diffraction (XRD), rheological characterization, infrared spectroscopy (FTIR), colorimetry, scanning electron microscopy (SEM), and tensile strength and impact. The TGA results have shown a single stage of mass loss for all samples, and thermal stability increase with filler concentration increase, which can be associated with the fiber-matrix interactions. In the XRD results, the PP has showed only the α phase remaining in the samples containing CB. In the rheological analysis, the complex viscosity has been maintained for samples containing 1% and 3% CB and pure PP, decreasing only for the 5% CB. In additional, It has been observed an enlargement of the molar mass distribution through a tendency reduction in the intersection point of G' and G". In the tensile strength, the elastic modulus has not undergone significant changes, the yield stress has decreased according to the load increasing, however it there have been significant changes with the load concentration increment. The impact strength has decreased for all samples with CB compared to pure PP. The microscopy has showed a good adhesion between fiber and matrix with bacterial cellulose clusters formation. By colorimetry process, it has been found caramelization of bacterial cellulose during the process of extrusion and injection, which causes browning of the samples. / Devido aos problemas ambientes causados pelos plásticos sintéticos, existe atualmente uma busca pela substituição desses materiais por materiais biodegradáveis. O estudo em relação a compósitos e nanocompósitos formados por materiais biodegradáveis e matrizes sintéticas vem crescendo nos últimos anos. Tem-se demostrado que esses materiais são muito promissores em relação aos processos de biodegradação, além de apresentarem propriedades melhores do que seus componentes puros. Neste trabalho foi visada a produção de um compósito com celulose bacteriana nanofibrilada em uma matriz de polipropileno. A produção das nanofibras de celulose bacteriana (CB) foi realizada em moinho coloidal. O material foi processado em extrusora dupla rosca nas proporções de 1%, 3% e 5% (p/p) de celulose bacteriana e como agente compatibilizante foi utilizado PP grafitizado com anidrido maleico. As amostras foram caracterizadas por análise termogravimétrica (TGA), difratometria de raio-x (DRX), espectroscopia de infravermelho (FTIR), análise reológica, resistência a tração e impacto, microscopia eletrônica de varredura (MEV) e colorimetria. Os resultados de TGA demostraram um único estágio de perda de massa para todas as amostras, e um aumento da estabilidade térmica conforme aumenta a concentração de carga, que pode estar associado com as interações fibra-matriz. Nos resultados de raio-x o PP apresentou apenas a fase α, mantendo-se para as amostras contendo CB. Nas análises reológicas, a viscosidade complexa manteve-se para as amostras de 1% e 3% de CB e para o PP puro, diminuindo apenas para a amostra com 5% de CB. Também observou-se um alargamento da distribuição da massa molar através de uma tendência na redução do ponto de cruzamento de G’ e G”. Na resistência à tração, o módulo elástico não sofreu alterações significativas, a tensão de escoamento reduziu com a inserção de carga, porém, não houve variação significativas com o aumento da concentração da carga. A resistência ao impacto reduziu para todas as amostras contendo celulose bacteriana em relação ao PP puro. A microscopia revelou uma boa adesão entre a fibra e a matriz com a formação de aglomerados de celulose bacteriana. Através da colorimetria verificou-se o processo de caramelização da celulose bacteriana durante o processo de extrusão e injeção, o que provoca o escurecimento das amostras.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / A celulose bacteriana (CB) desperta grande interesse por parte dos pesquisadores por apresentar estrutura nanomÃtrica, alto Ãndice de cristalinidade, alta porosidade, biocompatibilidade e elevado potencial tecnolÃgico. Diversas fontes de carbono alternativas tÃm sido estudadas para a produÃÃo de CB obtendo-se resultados satisfatÃrios quando compara-se com mÃtodos tradicionais que utilizam meio sintÃticos. O objetivo do presente trabalho consistiu em avaliar a produÃÃo de CB utilizando fontes agroindustriais (lÃquido de sisal e suco de caju) como substrato, no cultivo de Gluconacetobacter hansenii ATCC 23769 sob condiÃÃes estÃticas. Para tal, avaliou-se o efeito da concentraÃÃo de aÃÃcares, pH e suplementaÃÃo do meio com fontes de nitrogÃnio na produÃÃo de CB. Avaliou-se tambÃm a eficiÃncia da purificaÃÃo e o grau de cristalinidade da CB obtida. A maior produÃÃo de CB foi obtida apÃs cultivo da bactÃria por 10 dias utilizando meio obtido atravÃs da diluiÃÃo do lÃquido de sisal para 15 g/L de aÃÃcares, com ajuste de pH em 5 e suplementaÃÃo do meio com 7,5 g/L de extrato de levedura. Para o suco de caju a maior produÃÃo obtida foi de 0,34 g/L, apÃs 5 dias de cultivo e com meio ajustado para 50 g/L de aÃÃcares. Quanto Ãs caracterizaÃÃes tÃrmicas (TGA e DSC), Raio X e FTIR, a CB obtida a partir do lÃquido do sisal apresenta perfis semelhantes à CB obtida em meio padrÃo. Conclui-se que o lÃquido do sisal à o substrato mais promissor para a produÃÃo de CB. / Bacterial cellulose (BC) is an interesting biomaterial for researchers because it presents structure in nanoscale dimensions, high crystallinity degree, high porosity, biocompatibility, and high technological potential. Alternative carbon sources have been studied to replace traditional synthetic medium as a substrate for BC production, achieving satisfactory results. The aim of this work was to evaluate BC production using agro-industrial sources (sisal juice and cashew apple juice) as substrates in Gluconacetobacter hansenii ATCC 23769 cultivation under static conditions. The effects of sugars concentration, pH, and nitrogen sources supplementation were evaluated on the BC yield production. The efficiency of the BC purification process and the crystallinity degree of BC were also evaluated. The higher yield of BC was obtained after 10 days of cultivation in the medium based on sisal juice with the following parameters: 15 g/L of sugars, pH 5, and nitrogen supplementation with 7.5 g/L of yeast extract. When use cashew apple juice, the higher yield of BC was obtained after 5 days of cultivation in the medium with 50 g/L of sugars. The BC from the sisal juice medium presented similar TG, DSC, XRD, and FTIR characteristics to the BC from the standard medium. Thus, the sisal juice is a suitable substrate for BC production.