Gotowa bibliografia na temat „MICRO CELLULOSE PRODUCTION”

Cellulose is the most abundant and renewable natural semi-crystalline polysaccharide. This biopolymer is an inexhaustible source of natural fibers (NFs), and valuable raw material for the production of microparticles of microcrystalline (MCC) and powdered cellulose (PC), as well as other cellulose micro-products, which are widely used in biomedicine, production of food additives, plastics, and other materials. In addition, cellulose has a nano-fibrillar architecture that promotes the release of free cellulose nanofibers (CNFs) and nanocrystals (CNCs). This review article describes the preparation methods, structural characteristics, properties, and applications of different types of micro- (NFs, MCC, and PC) and nano-cellulose (CNFs, CNCs). Two main shortcomings hindering the wide application of various types of Nano cellulose (NC) were discovered, such as high production expenses and the difficulty of competing with commercial types of micro-cellulose. To reduce the production cost of NC, a waste-free technology can be used, which allows completely utilize materials and chemicals, and produce cheap nanocrystalline aggregates (NCA) with zero emission of liquid and solid waste. Due to the low cost, such a nanostructured product, NCA, will be quite competitive with commercial micro-celluloses (MCC, PC, etc.) and can be used, e.g., as filler and thickener.

Abstract This review aims to present cellulose as a versatile resource for the production of a variety of materials, other than pulp and paper. These products include fibers, nonwovens, films, composites, and novel derivatized materials. This article will briefly introduce the structure of cellulose and some common cellulose derivatives, as well as the formation of cellulosic materials in the micro- and nanoscale range. The challenge with dissolution of cellulose will be discussed and both derivatizing and nonderivatizing solvents for cellulose will be described. The focus of the article is the critical discussion of different shaping processes to obtain a variety of cellulose products, from commercially available viscose fibers to advanced and functionalized materials still at the research level.

Vegetable fibers produced from agroindustrial resources in the macro, micro and nanometric scales have been used as reinforcement in cementitious materials. The cellulosic pulp, besides being used as the reinforcing element, is also the processing fiber that is responsible for the filtration system in the Hatcheck method. On the other hand, the nanofibrillated cellulose has the advantage of having good mechanical performance and high specific surface, which contributes to improve the adhesion between fiber and matrix. In the hybrid reinforcement, with micro and nanofibers, the cellulose performs bonding elements with the matrix and acts as stress transfer bridges in the micro and nano-cracking network with the corresponding strengthening and toughening of the cementitious composite. Some strategies are studied to mitigate the degradation of the vegetable fibers used in cost-effective and non-conventional fiber cement, as well as to reach a sustainable fiber cement production. As a practical example, the accelerated carbonation curing at early age is a developing technology to increase the durability of composite materials: it decreases porosity, promotes a higher density in the interface generating a good fiber–matrix adhesion and a better mechanical behavior. Thus, the vegetable fibers are potentially applicable to produce high mechanical performance and sustainable cementitious materials for use in the Civil Construction.

This study was aimed to examine the production of microcrystalline cellulose (MCC) from tapioca solid waste (TSW), using HCl hydrolysis with various concentrations, i.e., 2 N, 2.5 N, 3 N, and 3.5 N. MCC was produced by delignifying the TSW with NaOH 20%, and bleaching with NaOCl 3.5% to produce α-cellulose, and subsequently hydrolyzing α-cellulose with three different HCl concentrations to produce MCC. The physicochemical properties of MCC were then analyzed, including Scanning Electron Micrograph (SEM), X-ray diffraction (XRD), and FTIR spectra. The results showed that hydrolysis with 2.0 N HCl resulted in a higher yield of 61.28%, α-cellulose content of 56.33%, moisture 6.25%, pH of 6.54; ash 0.23%, and water solubility 0.34%. SEM analysis showed the morphology and size of the MCC produced were like those of a commercial MCC (Avicel PH101), while the XRD analysis showed the higher concentration of HCl gave rise to an increased crystalline index. FT-IR spectrum analysis indicated that TSW, MCC produced, and commercial MCC had similar functional groups.

Incorporation studies of particles in different substrates with herbal assets growing. The objective of this work was the preparation and characterization of micro/nanoparticles containing cymbopogon nardus essential oil; and the incorporation of them on bacterial cellulose. For the development of the membranes was used the static culture medium and for the preparation of micro/nanoparticles was used the nanoprecipitation methodology. The incorporation of micro/nanoparticles was performed on samples of bacterial cellulose in wet and dry form. For the characterization of micro/nanoparticles were carried out analysis of SEM, zeta potential and particle size. For the verification of the incorporation of particulate matter in cellulose, analyses were conducted of SEM and FTIR. The results showed that it is possible the production and incorporation of micro/nanoparticles containing essential oil in bacterial cellulose membranes in wet form with ethanol.

Optimization have been done on the media for the growth of the isolated thermophiles bacteria from hot springs Rimbo Panti, the nutrients comprising variety of carbon sources such as CMC (carboxymethyl cellulose), avicell (micro crystalline cellulose), and cellobiose, with a variety of sources organic nitrogen, peptone, extracts yeast, tryptone, and urea, as well as variations consist of inorganic nitrogen sources, KNO3, NaNO3, (NH4)2SO4, and (NH4)NO3. Determination of cellulase activity performed using DNS reagent (3,5-dinitro salicylic acid). Maximum cellulase production with high activity based on the results of this research, the best of carbon source is CMC with optimum concentration 0.125%, inorganic nitrogen source is peptone with the optimum concentration of 0.3 to 0.4% and the inorganic nitrogen source is (NH4)2SO4 with optimum concentration of 0.2 - 0.25%. Optimization of size of inoculums obtained the optimum amount of inoculums 2%. Keywords: Optimization, thermophiles bacteria, cellulose, carbon sources, nitrogen sources

Aliphatic polyesters/cellulose composites have attracted a lot attention due to the perspectives of their application in biomedicine and the production of disposable materials, food packaging, etc. Both aliphatic polyesters and cellulose are biocompatible and biodegradable polymers, which makes them highly promising for the production of “green” composite materials. However, the main challenge in obtaining composites with favorable properties is the poor compatibility of these polymers. Unlike cellulose, which is very hydrophilic, aliphatic polyesters exhibit strong hydrophobic properties. In recent times, the modification of cellulose micro- and nanomaterials is widely considered as a tool to enhance interfacial biocompatibility with aliphatic polyesters and, consequently, improve the properties of composites. This review summarizes the main types and properties of cellulose micro- and nanomaterials as well as aliphatic polyesters used to produce composites with cellulose. In addition, the methods for noncovalent and covalent modification of cellulose materials with small molecules, polymers and nanoparticles have been comprehensively overviewed and discussed. Composite fabrication techniques, as well as the effect of cellulose modification on the mechanical and thermal properties, rate of degradation, and biological compatibility have been also analyzed.

Over the last decades, the negative impacts of fossil fuel on the environment and increasing demand for energy due to the unavoidable depletion of fossil fuels, has transformed the world’s interests towards alternative fuels. In particular, bioethanol production from cellulosic biomass for the transportation sector has been incrementing since the last decade. The bacterial pathway for bioethanol production is a relatively novel concept and the present study focused on the isolation of potential “cellulase-producing” bacteria from cow dung, compost soil, and termite gut and isolating sugar fermenting bacteria from palm wine. To select potential candidates for cellulase enzyme production, primary and secondary assays were conducted using the Gram’s iodine stain in Carboxy Methyl Cellulose (CMC) medium and the Dinitrosalicylic acid (DNS) assays, respectively. Durham tube assay and Solid-Phase Micro-Extraction (SPME) coupled with Gas Chromatography-Mass Spectrometry (GC-MS) was used to evaluate the sugar fermenting efficiency of the isolated bacteria. Out of 48 bacterial isolates, 27 showed cellulase activity where Nocardiopsis sp. (S-6) demonstrated the highest extracellular crude enzyme activity of endoglucanase (1.56±0.021 U) and total cellulase activity (0.93±0.012 U). The second-highest extracellular crude enzyme activity of endoglucanase (0.21±0.021 U) and total cellulase activity (0.35±0.021 U) was recorded by Bacillus sp. (T-4). Out of a total of 8 bacterial isolates, Achromobacter sp. (PW-7) was positive for sugar fermentation resulting in 3.07% of ethanol in broth medium at 48 h incubation. The results of the study revealed that Nocardiopsis sp. (S-6) had the highest cellulase enzyme activity. However, the highest ethanol percentage was achieved with by having both Bacillus sp. (T-4) and Achromobacter sp. (PW-7) for the simultaneous saccharification and fermentation (SSF) method, as compared to separate hydrolysis and fermentation (SHF) methodologies.

Multifunctional materials and devices with captivating properties can be assembled from cellulose and cellulose-based composite materials combining functionality with structural performance. Cellulose is one of the most abundant renewable materials with captivating properties, such as mechanical robustness, biocompatibility, and biodegradability. Cellulose is a low-cost and abundant biodegradable resource, CO2 neutral, with a wide variety of fibers available all over the world. Over thousands of years, nature has perfected cellulose-based materials according to their needs, such as function vs. structure. Mimicking molecular structures at the nano-, micro-, and macroscales existing in nature is a great strategy to produce synthetic cellulose-based active materials. A concise background of cellulose and its structural organization, as well as the nomenclature of cellulose nanomaterials, are first addressed. Key examples of nature-designed materials with unique characteristics, such as “eternal” coloration and water-induced movement are presented. The production of biomimetic fiber and 2D fiber-based cellulosic materials that have attracted significant attention within the scientific community are represented. Nature-inspired materials with a focus on functionality and response to an external stimulus are reported. Some examples of 3D-printed cellulosic materials bioinspired, reported recently in the literature, are addressed. Finally, printed cellulosic materials that morph from a 1D strand or 2D surface into a 3D shape, in response to an external stimulus, are reported. The purpose of this review is to discuss the most recent developments in the field of “nature-inspired” cellulose-based active materials regarding design, manufacturing, and inspirational sources that feature existing tendencies.

Les métalloprotéinases (MMPs) jouent un rôle crucial dans la migration des cellules souches hématopoïétiques saines (CSH) et malignes (LAL pré-B). La production de ces enzymes est régulée par de nombreux facteurs tels que les cytokines, les chémokines et d'autres éléments de la matrice extracellulaire (MEC). Dans ce travail, nous avons tout d'abord montré que l'acide hyaluronique (AH) comme la chimiokine SDF-1 induisait la production des MMPs par les progéniteurs CD34+ sains. Cette production est associée à une augmentation du calcium cytosolique. Contrairement à l'effet stimulateur de l'AH, celui du SDF-1 est dose dépendante. Nous avons également montré que les cellules CD34+ exprimaient la protéine membranaire Syndecan-4, un nouveau récepteur sélectif de SDF-1. D'autre part, nous avons étudié l'activité sécrétoire des cellules leucémiques pré-B LAL provenant de la moelle osseuse (MO) et du sang périphérique (SP) d'enfants malades. La production basale des MMPs ainsi celle stimulé par les cytokines (SDF-1, GM-CSF, b-FGF et VEGF) a été évaluée. Parallèlement l'expression génétique de ces gélatinases au niveau transcriptionnel a également été étudiée. Une large hétérogénéité a été observée parmi les patients étudiés. Les cytokines b-FGF et VEGF se sont révélées comme des stimulateurs de la production des MMPs, avec une préférence pour la MMP-2 tandis que le GM-CSF induisait essentiellement la production de la MMP-9, notamment dans les cellules du SP. Nous nous sommes intéressés aux mécanismes moléculaires de ces réponses cellulaires en utilisant des inhibiteurs spécifiques des trois voies de signalisation (NFkB, MEK1 et PI3K). L'expression de la MMP9 empruntait la voie de MEK1/PI3K tandis que celle de la MMP2 semblait être indépendante des voies étudiées. Nous avons mis en évidence que tous ces effets stimulateurs étaient calcium dépendants. De plus, b-FGF semblait favoriser la prolifération des cellules leucémiques en augmentant leur survie. A la suite de ces résultats, nous avons recherché si les cellules LAL pouvaient elles-mêmes produire ces cytokines stimulatrices de façon autocrine. Nous avons détecté la présence de l'ARNm de VEFG dans les cellules pré-B chez la majorité des patients étudiés. L'ARNm de VEGF-R1 a été observé pour tous les patients, alors que ceux de VEGF-R2 et VEGF-R3 ont été détectés chez une partie des patients. L'ensemble de ces résultats indique que les différents éléments de la MEC étudiés dans ce travail (AH, SDF-1, GM-CSF, b-FGF et VEGF) jouerait un rôle important dans la migration des cellules souches saines et leucémiques via leur action régulatrice sur la production des MMPs. Ce travail constitue une base pour suggérer de nouvelles stratégies thérapeutiques
The metalloproteinases (MMPs) play a key role in the migration of haematopoietic stem cells. The production of these enzymes is regulated by different components of the extracellular matrix (ECM). In this study, we have shown that in normal CD34+ cells hyaluronic acid (HA) as well as SDF-1, induces MMPs secretion. This stimulatory effect is associated with an increase of cytosolic calcium. In contrast to HA induced-effect, SDF-1-induced MMPs secretion appears to be dose-dependent. We have also shown that CD34+ cells express syndecan-4, a selective membrane receptor of SDF-1. Besides, we have studied the secretory activity of pre-B acute lymphoblastic (ALL) cells derived from bone marrow (BM) or peripheral blood (PB) of leukaemic children. The MMPs secretion has been evaluated at basal and stimulated (by SDF-1, GM-CSF, b-FGF and VEGF) levels. A large heterogeneity has been observed among the studied patients. VEGF and b-FGF are found to be able to provoke predominantly MMP-2 secretion while GM-CSF mainly induces MMP-9 production, more particularly in SP cells. The molecular mechanisms involved in these responses have been investigated by using specific inhibitors of NFB, MEK1 and PI3K pathways. The expression of MMP-9 has appeared to be mediated through MEK1/PI3K pathways. It has been shown that all stimulatory effects observed in the present work are calcium-dependent. In addition, b-FGF favours the leukaemia proliferation by strengthening cell survival. Thereafter, we have investigated whether the pre-ALL cells themselves could produce through an autocrine loop these stimulating cytokines. The presence of mRNA of VEGF in pre-B ALL cells has been detected in most of studied patients, while the presence of mRNA of VEGF-R1 has been observed in all patients. Altogether, the present findings strongly suggest that different ECM components studied in this work (HA, SDF-1, GM-CSF, b-FGF and VEGF) would play a crucial role in the migration of leukaemic and normal haematopoietic stem cells by regulating the MMPs secretion. These data constitute a basis to consider new strategies of therapies

L'interleukine-12 (IL-12), principalement produite par les cellules dendritiques (CD) activées, tient une place centrale au sein du système immunitaire, en établissant un lien entre la réponse immune innée et la réponse adaptative. Les CD sont présentes dans la majorité des tissus et sont en constante interaction avec leur environnement cellulaire. L'objectif de ce travail de thèse est d'analyser le rôle de certains facteurs cellulaires environnementaux, sur le développement et la fonctionnalité des CD murines. Nous montrons que les CD issues de souris déficitaires en lymphocytes T ne produisent pas d'IL-12 après stimulation. La reconstitution lymphocytaire T de ces souris induit une augmentation de l'hématopoi͏̈èse mais surtout restaure la capacité des CD à sécréter de lIL-12 en réponse à une activation. Les lymphocytes T potentialisent donc la production d'IL-12, principalement en régulant la transcription du gène codant pour la sous-unité IL-12p35. A l'inverse, nous mettons en évidence que les fibroblastes, quelle que soit leur origine tissulaire, inhibent de façon spécifique, via un(des) facteur(s) soluble(s), la production d'IL-12 par les CD spléniques murines en culture ou fraîchement purifiées. Ce(s) facteur(s) inhibe(nt) également la maturation phénotypique des CD ainsi que la transcription du gène IL-12p35. L'ensemble de ces résultats montre que la production d'IL-12 par les CD est régulée par plusieurs facteurs cellulaires du micro-environnement dans lequel baignent les CD et souligne le rôle fondamental de la coopération cellulaire au cours du développement d'une réponse immune appropriée.

L'approvisionnement en énergie et le changement climatique représentent aujourd'hui deux problèmes remarquables qui doivent être surmontés par la société dans un contexte de croissance de la demande d'énergie. La reconnaissance de ces problèmes par l'opinion publique encourage la volonté politique de prendre différentes actions pour les surmonter de façon aussi rapide qu'efficace. Ces actions se basent sur l'augmentation de l'efficacité énergétique, la diminution de la dépendance sur les énergies fossiles et la réduction des émissions de gaz à effet de serre. Dans ce contexte, les systèmes électriques subissent des changements importants au niveau de leur planification et de leur gestion. D'une part, les structures verticalement intégrées sont en train d'être remplacées par des structures de marché d'électricité donnant naissance à plusieurs acteurs au niveau du fonctionnement des marchés et de la production, distribution et commercialisation d'électricité. D'autre part, les systèmes électriques qui se basaient sur la production d'énergie issue de grandes centrales génératrices voient arriver aujourd'hui la fin de vie de ces grandes centrales. Le rôle de la production répartie d'électricité à partir de technologies telles que l'éolien et le solaire devient de plus en plus important dans ce contexte. Cependant, l'intégration à grande échelle de ces types de ressources réparties pose plusieurs défis liés, par exemple, aux incertitudes associées à la variabilité de la production de ces ressources. Toutefois, des systèmes combinant des outils avancés de prédiction de l'éolien ou du solaire peuvent être combinés avec des éléments contrôlables tels que des moyens de stockage d'énergie, des turbines à gaz ou de la demande électrique contrôlable, peuvent être créés dans le but de réduire les impacts associés à ces incertitudes. Ce travail de thèse traite de la gestion, sous conditions de marché libéralisé d'électricité, de ce type de systèmes qui fonctionnent comme des sociétés indépendantes qui sont ici nommées cellules des systèmes électriques. À partir de la bibliographie existante, une vision unifiée des problèmes de gestion des systèmes électriques est proposée comme un premier pas vers la gestion d'ensembles de cellules des systèmes électriques dans un cadre de gestion multi-cellule. Des méthodologies pour la gestion journalière et optimale de ce type de cellules sont proposées, discutées et évaluées dans un cadre à la fois déterministe et stochastique, ce dernier intégrant dans le processus de gestion les incertitudes liées au problème. Les résultats obtenus montrent que l'utilisation des approches proposées peut conduire à des avantages importants pour les opérateurs chargés de la gestion de cellules des systèmes électriques.

Orientadores: Francisco Maugeri Filho, Gonçalo Amarante Guimarães Pereira
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O etanol vem novamente despertando de modo crescente a atenção de pesquisadores, empresas e governo, devido ao aumento do preço do petróleo e perspectivas de esgotamento das fontes não-renováveis de combustíveis fósseis, bem como, preocupações de natureza ambiental, relacionadas à emissão de substâncias que comprometem o meio ambiente. O estabelecimento de metas extremamente ambiciosas para aumento do consumo do etanol nos próximos anos requer um aumento substancial da produção de etanol e, nesse sentido, estimula a pesquisa e o desenvolvimento de tecnologias que permitem o uso de novas matérias-primas na produção de etanol, como a biomassa lignocelulósica. No entanto a ampliação desta tecnologia é limitante devido ao alto custo das enzimas, indicando desta forma a importância da busca por novas fontes de enzimas capazes de contribuir para este processo. Em face disto, este trabalho teve como objetivo estudar as propriedades lignocelulolíticas de micro-organismos silvestres isolados de diversas regiões brasileiras, bem como realizar um estudo genético visando à produção de bioetanol. Inicialmente foi realizada uma seleção das cepas que apresentaram capacidade de produção de celulases, a partir de micro-organismos silvestres isolados de diversas regiões do país. Após a seleção, a cepa nomeada AAJ6 foi selecionada como potencial produtor de celulases e identificada molecularmente como Acremonium strictum. Posteriormente, foram realizados estudos de recuperação, purificação e caracterização enzimática das enzimas produzidas pelo microorganismo em estudo. A precipitação com acetona 60% foi o método que resultou em melhores porcentagens de recuperação, registrando 80,67% de recuperação para as endoglucanases (CMCase), 65% para a atividade de papel de filtro (FPase) e 25% para celobiase. Em relação à purificação, a resina Q-Sepharose foi selecionada como mais eficiente para a purificação das enzimas do complexo celulase produzidas por Acremonium strictum. Quanto à caracterização enzimática, as faixas de temperatura e pH estudadas não tiveram diferença significativa (p<0,05) em relação à atividade de endoglucanase (CMCase). Já para a atividade de FPase e celobiase, a faixa temperatura ótima foi de 54 a 57 °C e o pH ótimo foi de 4,7. Para a b-glicosidase, apenas a temperatura foi significativa, favorecendo temperaturas mais elevadas (54 a 57 °C) para a atividade enzimática. Paralelamente conduziram-se fermentações para produção de celulases empregando diferentes substratos, tanto substratos comerciais (carboximetilcelulose, SERVACEL® e AVICEL®) como bagaços de cana-de-açúcar pré¿tratados com diferentes intensidades. O bagaço de cana submetido a um pré-tratamento leve (12 kgf/cm²; 188,5°C) foi o que melhor induziu o micro-organismo em estudo a produzir as maiores atividades celulolíticas em comparação aos demais substratos estudados, registrando valores máximos de CMCase de 134,42 U/L em 240 horas de fermentação, 10,82 U/L de FPase em 192 horas, 27,72 U/L de celobiase em 96 horas e 3,48 U/L de b-glicosidase em 240 horas. Com o avanço da biotecnologia e da biologia molecular, a identificação de genes presentes num determinado micro-organismo já se tornou essencial. Em face disto, foi realizado o sequenciamento 454 do genoma do Acremonium strictum e dois genes de celulases foram identificados, sendo um gene de endoglucanase da família 74a e um gene de b-glicosidase. Estas enzimas foram isoladas, sequenciadas e clonadas em E.coli através do vetor pGEM-T Easy de forma que futuros trabalhos possam abordar os produtos de expressão destas enzimas em Saccharomyces cerevisiae visando à produção de bioetanol de segunda geração
Abstract: Ethanol has increasingly attracted the attention of researchers, companies and governments due to the increase in oil prices and prospects of depletion of nonrenewable fossil fuels, as well as environmental concerns related to emissions of substances that compromise the environment. Excessively ambitious goals for the increased consumption of ethanol in the for the years ahead requires a substantial increase in ethanol production and, accordingly, encourages research and development of technologies that allow the use of new raw materials for ethanol production, such as lignocellulosic biomass. However the expansion of this technology is limited due to the high cost of enzymes, thus indicating the importance of searching for new sources of enzymes able to contribute to this process. In the face of this, the present work intended to study the lignocellulolytic properties of wild microorganisms isolated from various regions of Brazil as well as conducting a genetic study aimed at producing bioethanol. Initially a selection of strains that were capable of producing cellulases was carried out. Than, the the selected strain, named AAJ6 and molecularly identified as Acremonium strictum, was shown to be a potential producer of cellulases. Subsequently, studies were performed for recovery, purification and characterization of the enzymes produced by this microorganism. Precipitation with 60% acetone was the method that led to improved recovery percentages, about 80%, for the endoglucanases (CMCase), 65% for filter paper activity (FPase) and 25% for cellobiase. With regard to purification, choromatographic column with Q-Sepharose resin was selected as the most efficient for the purification of the cellulase enzyme complex produced by Acremonium strictum. As enzymatic characterization, the temperature and pH ranges studied did not differ significantly (p<0.05) compared to the activity of endoglucanase (CMCase). As for the cellobiase and FPase activity, the optimum temperature range was 54 to 57 °C and optimum pH was 4.7. For the b-glucosidase, only temperature was significant, favoring higher temperatures (54 to 57 °C) for enzyme activity. Parallel fermentations were conducted for cellulase production using different cellulosic substrates (carboxymethylcellulose, SERVACEL® and AVICEL ®) and sugarcane bagasse pretreated with different intensities. Bagasse that underwent t mild pretreatment (12 kgf/cm², 188.5 °C) was the best inducer for microorganism under study, and led to the highest cellulolytic activities, being the maximum values 134.42 U/L U/L for CMCase after 240 hours of fermentation, 10.82 U/L for FPase after 192 hours, 27.72 U/L for cellobiase after 96 hours and 3.48 U/L for b-glucosidase after 240 hours. At the current stage of biotechnology and molecular biology, the identification of genes present in a given micro-organism has become essential. In view of this, the 454 sequencing of the genome of Acremonium strictum was carried out and two cellulase genes were identified, being an endoglucanase of the family 74a gene and b-glucosidase gene. These enzymes were isolated, sequenced and cloned into E. coli using the pGEM-T Easy vector so that future work can address the expression products of these enzymes in Saccharomyces cerevisiae in order to produce second generation bioethanol
Doutorado
Engenharia de Alimentos
Doutora em Engenharia de Alimentos

La mise au point d'un système pour la sélection in vitro de deux solanacées diploïdes et autogames résistantes a l'atrazine, au chlortoluron et au terbutryne, est décrite. Les effets de ces produits ont été détermines sur des cultures d'organes (explants différencies) et sur des cals (tissus indifférencies). Aucune sélection n'est possible a partir de disques foliaires, entre-nœuds, anthères et cals non chlorophylliens. On procede ensuite au repiquage des tissus sur un milieu organogène. On réalise le micro greffage des apex des tiges ainsi formées sur de jeunes plantes issues de germination. On met en évidence que le caractère de résistance est transmis a certains des embryons produits par les plantes greffées

Micro cellulose, the versatile biopolymer derived from cellulose, which is flexible and numerous, has a lot of potential for use in a variety of industrial applications. The isolation, treatment and cellulose characterization produced from organic waste sources are the main topics of this study. Establishing a sustainable and effective process for extracting micro cellulose from waste materials will help protect the environment and open up new waste management opportunities. The research methodology has a number of steps. Initially, organic waste products (Apple peels, Potato peels) are collected and processed. Advanced analytical methods, such as Fourier transform infrared spectroscopy (FTIR), Particle Size Distribution are used to characterize the resultant micro cellulose. The produced micro cellulose can be used in a variety of industries, including the textile industry, biomedical equipment, packaging materials and the creation of renewable energy. Overall, this research helps to provide a sustainable method for harvesting micro cellulose from organic waste sources. It encourages waste management procedures while lowering reliance on non-renewable resources by turning garbage into a useful resource. The final results of the micro cellulose characterization will enable the production process to be optimized and new uses to be investigated, promoting circular economy and more sustainable.

The theoretical foundations for identifying the main determinants of the development of the woodworking industry in the countries of the world have been deepened. Based on the results of bibliometric analysis, promising areas of scientific research on the development of the world woodworking industry have been identified: production of biomass, cellulose and other wood materials; preservation of forests and ensuring sustainable development; development of Industry 4.0 and innovative technologies; development of a circular and green economy; improving product quality and optimizing production processes. The structure of the woodworking industry in Ukraine and countries of the world has been analyzed. Using the matrix approach, positioning of Ukraine and the countries of the world in the plane of coordinates of the volume of output of the woodworking industry by type of economic activity and their share in the volume of production of the woodworking industry has been carried out. The methodological approach to the integral assessment of the progressive structure of the country’s woodworking industry has been improved. It is based on the classification of the levels of production and technological redistribution of the woodworking 83industry and includes the following types of economic activities of the woodworking industry: production of lumber; veneer production; production of wood-based panels, for each of which the coefficient of progressivity is set.

Biofuels are emerging as integral and necessary research areas towards clean, next generation energy production, while providing alternative sources of sustainability. In addition to advancements in nanotechnology, many obstacles remain on the way for producing economically viable biofuels such as the challenges involved in the breakdown of cellulose, hemicelluloses, and lignin found in woody biomass. The use of micro-algae as a feedstock in biofuel has already been impacted by the advancements of nanotechnology. However, interdisciplinary breakthroughs are needed to make biofuels viable contenders as replacements for traditional fossil fuels. The authors discuss recent advances, benefits, and challenges facing nanotechnology in accordance with furthering our understanding and improving the state of biofuel manufacturing, including the implementation of nanotechnology in other aspects of biofuels production, such as cracking catalyst design, carbon nanotube electrodes for fuel cells, and enzymatic production of biofuels.

Biological structures such as termite nests, silk worm cocoons and honey bee combs integrate material, structure and form to produce biodegradable polymers and composites. Synthetic production of biomaterials through additive or woven processes has failed to achieve comparable material properties to their natural counterparts. For example, cellulose-based biocomposites have markedly less strength and toughness than cellulose micro and nanofibers found in nature. Termites produce a cellulose-based composite called “Carton” which serves as construction material for their nests. The process by which termites produce Carton is similar to the manufacturing process for electrospun cellulose fibers. Studying how termites produce Carton, a functionally driven material, can inform a design methodology for synthetic production of biomaterials. Here we characterize material composition of Carton by conducting Raman spectroscopy on samples produced by two termite varieties. By leveraging the knowledge accumulated from millenia of evolution we can use nature as a design template for novel material production.

In this paper, we present a novel design of bilayer polydimethylsiloxane (PDMS) microchannel formed by bifurcated junction, from which each curved branch lies on the upper and lower layer, respectively. With this 3D platform, we aim to investigate droplet formation and subsequent fission in a multiphase system using non-Newtonian fluids, which are ubiquitous in daily life and have been widely used in industrial applications including biomedical engineering, food production, personal care and cosmetics, and material synthesis. Numerical model has been established to characterize the non-Newtonian effect to droplet fission and associated breakup dynamics when droplet flows through 3D bifurcated junction, where droplets can deform significantly on account of the confining geometric boundaries, and the flow of the surrounding non-Newtonian liquid, both of which control the deformation and breakup of each mother droplet into two daughter droplets. Dispersions of sodium carboxymethyl cellulose in water, and dispersions of polyvinylchloride in dioctylphthalate have been used as model fluids in the study, with the former one possessing shear-thinning behaviour, while the latter one possessing shear-thickening behaviour. The understanding of the droplet fission in the novel microstructure will enable more versatile control over the emulsion formation when non-Newtonian fluids are involved. The model systems in the study can be further developed to investigate the mechanical property of emulsion templated particles such as drug encapsulated microcapsules when they flow through complex media structures, such as blood capillaries or the porous tissue structure, which feature with bifurcated junction.

MICROWAVE WOOD CHIP TREATMENT USE IN CHEMICAL PULP MANUFACTURING (TECHNICAL-ECONOMIC ASSESMENT) A. Leshchinskaya Plekhanov Russian University of Economics. 36 Stremyannyy Pereulok, 115093 Moscow, Russia, e-mail: alixfl@mail.ru] Keywords: chemical pulping, microwave wood modification, pulp, softwood, wood chips. Large volumes of cellulose are produced from wood chips by chemical methods. Low permeability of many wood species causes problems in the chemical pulp industry. These include: very long cooking times, high chemical consumption, large material losses, high energy consumption, and environmental pollution. New microwave (MW) wood modification technology can provide an increase in wood permeability for liquids and gases, which solves many of these problems. The technology works by applying intensive MW power to green wood, which generates steam pressure within wood cells. High internal pressure destroys weak elements of wood structure, opens pores and forms micro and macro cracks. A several thousand-fold increase in wood permeability can be achieved in species previously found to be impermeable to liquids and gases. It allows a significant increase in the speed of pulp cooking and improves a production processes. The study of the technology showed radical potential improvements in the pulp industry through: increase in mill throughput significant reduction of chemical consumptionreduction of energy consumption • increase in pulp quality and yield improvement of environmental performance. Pulp manufacturing process includs timber chipping, microwave chip treatment, steaming, cooking, washing, and pulp making. The use of MW wood chip treatment in pulp mills with outputs of 50,000 to 500,000 air dry tons (ADT) per year requires MW equipment with power from 1000 to 10,000 kW. Economic modelling of this technology used in different pulp mill conditions allowed assessment of the effect of capital costs, electricity costs, labour costs and other cost components to specific total costs of MW chip processing. Economic assessment of MW technology application showed that specific costs of softwood chip processing at electricity costs of 0.08 - 0.12 US$/kWh are 25.4 -33.7 US$/ADT of pulp. Electricity costs form the most significant part of the total specific costs of MW processing and form 51-69% shear in the total specific costs. Under the same conditions capital costs form 15-20% shear, and labour costs form 5-18% shear of the total specific costs. The electricity cost increase from $0.04 to $0.24/kWh provides specific MW processing cost rise by 2.7 to 3.1 times at pulp mill output range 50,000 to 500,000 ADT/year. New technology use allows benefits up to 7 – 22 Mil US$ per year for pulp mills with output of more than 200,000 ADT/year. The technology can be used by pulp mills with batch and continuous digesting and is not limited by mill throughput. Ecological impacts and high economic advantages of this MW technology application in pulp and paper industry provide good opportunity for commercialisation.

Solid particle erosion is a mechanical process in which material is removed from a surface due to impacts of solid particles transported within a fluid. It is a common problem faced by the petroleum industry, as solid particles are also produced along with oil and gas. The erosion not only causes economic losses resulting from repairs and decreased production but also causes safety and environmental concerns. Therefore, the metal losses occurring in different multiphase flow regimes need to be studied and understood in order to develop protective guidelines for oil and gas production equipment. In the current study, a novel non-invasive ultrasonic (UT) device has been developed and implemented to measure the metal loss at 16 different locations inside an elbow. Initially, experiments were performed with a single-phase carrier fluid (gas-sand) moving in the pipeline, and the erosion magnitudes are compared with Computational Fluid Dynamics (CFD) results and found to be in good agreement. Next, experiments were extended to the multiphase slug flow regime. Influence of particle diameter and liquid viscosity were also studied. Two different particle sizes (150 and 300 micron sand) were used for performing tests. The shapes of the sand are also different with the 300 micron sand being sharper than the 150 micron sand. Three different liquid viscosities were used for the present study (1 cP, 10 cP and 40 cP). Carboxymethyl Cellulose (CMC) was used to increase the viscosity of the liquid without significantly altering the density of the liquid. While performing the UT experiments, simultaneous metal loss measurements were also made using an intrusive Electrical Resistance (ER) probe in a section of straight pipe. The probe in the straight pipe is an angle-head probe which protrudes into the flow with the face placed in the center of the pipe. The UT erosion measurements in a bend are also compared with experimental data obtained placing an intrusive flat head ER probe flush in a bend, and the results were found to be in good agreement. Finally, the non-invasive NanoUT permanent placement temperature compensated ultrasonic wall thickness device developed for this work has the capability of measuring metal loss at many locations and also identifying the maximum erosive location on the pipe bend.

Solid particle erosion is a mechanical process in which material is removed from a surface due to impacts of solid particles transported within a fluid. It is a common problem faced by the petroleum industry, as solid particles are also produced along with oil and gas. The erosion not only causes losses resulting from repairs and decreased production but also causes safety and environmental concerns. Therefore, the metal losses occurring in different multiphase flow patterns need to be studied and understood in order to develop protective guidelines for oil and gas production equipment. A large scale boom loop, which is capable of generating a wide variety of multiphase flow regimes was used for conducting experiments. Specifically, this work examines erosion measurements in multiphase slug and annular flow regimes. These flow regimes are selected since they produce higher metal losses than other flow regimes, and they also occur for a wide variety of operating conditions. Experiments are performed on a horizontal 0.0762 m (3-inch) diameter pipe, with superficial gas velocities ranging from 15.2 m/s (50 ft/s) to 45.7 m/s (150 ft/s) and superficial liquid velocities ranging from 0.46 m/s (1.5 ft/s) to 0.76 m/s (2.5 ft/s), for liquid viscosities of 1 cP and 10 cP. Carboxymethyl Cellulose (CMC) was used to increase the viscosity of the liquid without significantly altering the density of the liquid. Three different sand sizes (20, 150 and 300 micron sand) were used for performing tests. The shapes of the sand are also different with the 20 and 300 micron sand being sharper than the 150 micron sand. Erosion measurements are taken using Electrical Resistance (ER) probes which relate the change in electrical resistance to the change in the thickness of an exposed element resulting from erosion. Two probes are placed in a bend and another probe is placed in a straight section of pipe. The probes in the bend are flat-head probes, and they are placed flush with the outer wall in the 45 and 90 degree positions. The probe in the straight pipe is an angle-head probe which protrudes into the flow with the face placed in the center of the pipe. Under the flow conditions investigated, the angle-head probe measures the maximum erosion due to its placement. Results demonstrate a significant increase in the metal loss occurs when increasing the superficial gas velocity and decreasing the superficial liquid velocity. The effect of changing the viscosity of the liquid is not as clear. Results suggest a slight increase in metal loss by increasing the viscosity from 1cP to 10 cP in slug flow. However, for annular flow, higher erosion occurs for the lower liquid viscosity considered.