In this study, a sustainable packaging system was developed to provide food safety and security. Soy protein isolate (SPI) was enzymatically modified by transglutaminase under different conditions to ensure desirable and optimized enzyme crosslinking activity before film preparation. Physicochemical properties including viscosity and molecular weight distribution of the modified proteins and films were measured. Results confirmed the enzymatic treatment is an effective way to modify the SPI based biopolymeric film. Modified films with the enzyme had significant increases in tensile strength (TS), percent elongation (%E), initial contact angle, and a reduction in swelling and protein solubility properties compared to the control films. FTIR and XRD spectra revealed that the enzyme treatment modified the structure of SPI film matrix. The optimal film preparation conditions achieved in this part were protein denaturation temperature 80 °C, and enzyme incubation time 2hr. We attempted to enhance antioxidant activity of enzymatically modified SPI film with the addition of two types of lignin, alkali lignin (AL) and lignosulphonate (LSS), at different concentrations. Results indicated that AL carried higher radical scavenging ability than LSS. Films containing AL showed high absorption in the UV region, and this UV-blocking ability increased with increasing lignin concentration. Deconvoluted FTIR spectra and XRD results suggested that the addition of lignin caused some changes in secondary structure of the protein matrix. The addition of lignin improved TS and thermal stability of films, but reduced %E as a function of lignin concentration. Radical scavenging activity and UV-blocking ability alongside improvement in physicochemical properties of enzymatic modified SPI film with lignin motivated us to apply this bioplastic in two types of oil, soy oil and fish oil. Results revealed that applying enzymatically modified SPI film with AL and LSS in the inner layer of a soy oil packaging system, decreased oxidation rate to around 75%, and pentanal production to about 40% of control. UV-blocking ability of AL caused reduction in oxidation rate for more than 75% compared with the normal packaging system. The effectiveness of this active packaging system in soy oil was greater than fish oil. Thus, the developed biopolymeric materials may have application to food packaging. / Ph. D.

Microtubules are cytoskeletal protein polymers relevant to a wide range of cell functions. In order to polymerize, the constituent tubulin subunits need to bind the nucleotide GTP, but its subsequent hydrolysis to GDP in the microtubule lattice induces depolymerization. The resulting behaviour of stochastic switching between growth and shrinkage is called dynamic instability. Both dynamic instability and microtubule mechanical properties are integral to many cell functions, yet are poorly understood. The present study uses thermal fluctuation measurements of grafted microtubules with different nucleotide contents to extract stiffnesses, relaxation times, and drag coefficients with an unprecedented precision. Both the stiffness and the relaxation time data indicate that stiffness is a function of length for GDP microtubules stabilized with the chemotherapy drug taxol. By contrast, measurements on microtubules polymerized with the non-hydrolizable GTP-analogue GMPCPP show a significantly higher, but constant, stiffness. The addition of taxol is shown to not significantly affect the properties of these microtubules, but a lowering of the GMPCPP content restores the length-dependent stiffness seen for taxol microtubules. The data are interpreted on the basis of a recent biopolymer model that takes into account the anisotropic architecture of microtubules which consist of loosely coupled protofilaments arranged in a tube. Using taxol microtubules and GMPCPP microtubules as the respective analogues of the GDP and GTP state of microtubules, evidence is presented that shear coupling between neighbouring protofilaments is at least two orders of magnitude stiffer in the GTP state than in the GDP state. Previous studies of nucleotide effects on tubulin have focussed on protofilament bending, and the present study is the first to be able to show a dramatic effect on interprotofilament bonds. The finding’s profound implications for dynamic instability are discussed. In addition, internal friction is found to dominate over hydrodynamic drag for microtubules shorter than ∼ 4 μm and, like stiffness, to be affected by the bound nucleotide, but not by taxol. Furthermore, the thermal shape fluctuations of free microtubules are imaged, and the intrinsic curvatures of microtubules are shown for the first time to follow a spectrum reminiscent of thermal bending. Regarding the extraction of mechanical data, this assay, though previously described in the literature, is shown to suffer from systematic flaws.

The presented dissertation thesis deals with the polymer polyhydroxybutyrate and other biopolymers as a basic building block for the construction of micro- and nanoscopic structures and materials used in food and cosmetics. In the theoretical part, current literary review is prepared to introduce the basics of this application field. The practical part of the work is composed of three blocks developed during the doctoral study. In the first and most important part are summarized comments to the academic and patent outputs, where among the academic ones it is possible to find two peer-reviewed articles dealing with the electrostatic and wet spinning of PHB and properties of prepared materials. The patent outputs consist of several accepted and applied projects, which summarize results on both PHB spinning methods, but also on general approaches enabling the processing of PHB into forms enabling many applications in food and cosmetics. Second part was focused on the patented composition of the UV protection cream based on the prepared nanoscopic and micro- morphologies of PHB. The third block summarizes results focused predominantly on the electrostatic spinning of PHB and other biopolymers. Finally, a short chapter containing a brief description of projects that were in a way related to the dissertation topic, but rather practical development work in Central Tanzania and West Africa, which draw on knowledge and contacts gained during studies at FCH BUT Brno.

A quitosana é um biopolímero funcional com grande potencial de desenvolvimento, podendo gerar diferentes tipos de materiais com variadas funções. Conforme modificações na sua estrutura, a quitosana tem encontrado aplicações nas mais diversas áreas, possuindo um grande leque de aplicações. Apesar do crescente uso da quitosana e do aumento das pesquisas por novas aplicações, a prospecção de outras opções de fontes (que não crustáceos) de quitosana não têm sido consistentemente apresentadas. O objetivo do presente projeto é realizar a prospecção quantitativa e qualitativa de uma nova fonte renovável de quitosana. Temos como uma fonte alternativa para a produção de quitosana, os blatódeos que são comumente conhecidos como baratas. Eles são organismos terrestres que apresentam uma reprodução consideravelmente rápida, se adaptam aos mais variados ambientes e tem o custo de criação baixíssimo devido à sua fácil adaptação ao ambiente e alimentação. Além disso, os blatódeos não possuem sazonalidade, e ainda realizam ecdises, podendo-se utilizar as exúvias para a produção de quitosana. Foram determinados o processo e o rendimento do processo de obtenção de quitosana a partir de blatódeos (Phoetalia pallida). Os blatódeos foram submetidos a tratamento com solução de hidróxido de sódio 50% (p/v) em temperatura de 120 ºC por sete tempos diferentes (1, 2, 3, 6, 10 e 20 horas). As quitosanas obtidas foram caracterizadas mediante técnicas de espectroscopia no Infravermelho (FTIR), comportamento térmico (TG/DTG e DSC), difração de raios-x, viscosimetria e teste de solubilidade. A obtenção de quitosana a partir de blatódeos apresentou vantagens em relação à produção a partir de crustáceos: reduzido número de etapas do processo e dispensa o tratamento com HCl, que é um poluente. O processo de obtenção de quitosana teve rendimento de aproximadamente 15%, variando de acordo com o tempo de reação. De uma maneira geral, as quitosanas de barata apresentaram características semelhantes à quitosana de camarão. / Chitosan is a functional biopolymer with great development potential, which can generate different types of materials with several purposes. Depending on changes in its structure, chitosan has found applications in several areas, having a wide range of applications. Despite the increasing use of chitosan and the increase in research for new applications, the exploration of other options as sources of chitosan (other than shellfish) have not been consistently shown. The goal of this project is to conduct a quantitative and qualitative exploration of a new renewable source of chitosan. Blattaria, commonly known as cockroaches, are an alternative source for the production of chitosan. They are terrestrial organisms that present a considerably fast reproduction, adapt to many different environments and have a very low cost of growing, due to its easy adaptation to the environment and food. Moreover, the cockroaches don´t present seasonality and still perform ecdysis, where the exuvia can be used to produce chitosan. The process and the efficiency of the process of obtaining chitosan from the cockroaches, Phoetalia pallida, were determined: they were treated with a solution of sodium hydroxide 50% (w / v) at a temperature of 120 °C for seven different time periods (1, 2, 3, 6, 10 and 20 hours). Chitosans obtained therefrom were characterized by Infrared spectroscopy (FTIR), thermal behavior (TG / DTG and DSC), x-ray diffraction, viscosimetry and solubility test. Obtaining chitosan from cockroaches showed advantages over the production from shellfish: reduced number of process steps and not requiring treatment with HCl, which is a pollutant. The process of obtaining chitosan showed an efficiency of approximately 15%, depending upon the reaction time. In general, the cockroach chitosan showed characteristics similar to shrimp chitosan.

Orientador: Clóvis Augusto Ribeiro / Coorientador: Mary Rosa Rodrigues de Marchi / Banca: Mirabel Cerqueira Rezende / Banca: Ana Maria de Guzzi Plepis / Banca: Roselena Faez / Banca: Sandra Mara Martins Franchetti / Resumo: O PHB (poli 3-hidroxibutirato), um homopolímero importante pelas suas propriedades de biodegradabilidade e biocompatibilidade, que quando submetido aos processamentos reológicos tradicionais de extrusão e injeção o PHB sofre degradação térmica e com isso os materiais produzidos possuem propriedades mecânicas que limitam seu uso. Considerando o monômero do PHB, ácido 3- hidroxibutírico, foi proposto o estudo da interação dos ácidos málico, glicólico, tartárico e mandélico que possuem os grupos funcionais hidroxila e carboxila em suas estruturas. Estes hidroxiácidos podem ser obtidos a partir de fontes naturais e assim pode-se obter um novo material polimérico com as mesmas propriedades de biodegradabilidade e biocompatibilidade do PHB4V% (poli 3-hidroxibutirato contendo 4% do monômero 3-hidroxivalerato), porém com maior potencial de aplicação. Por meio de estudo de comportamento térmico empregando as técnicas de TG-DTA e DSC foi possível definir qual das amostras de filmes apresentaram menor temperatura de fusão cristalina, transição vítrea e por outro lado maior temperatura de cristalização e maior estabilidade térmica. A partir de estudo cinético foi determinado o fator pre exponencial de Arrhenius (A) e energia de ativacao (E) da reação de cristalizacao analisada por DSC, no qual foi observado que o ácido tartárico interagiu com as cadeias do PHBV4%, enquanto que o ácido málico apresentou-se como um aditivo no filme. Amostras dos filmes de PHBV4% com hidroxiácidos derivatizados com álcool isoamílico foram analisadas por GC-FID para identificação e quantificação monomérica. Aplicando a metodologia validada foi possível analisar amostras dos filmes com segurança analítica simultaneamente os derivados dos ácidos 3-hidroxibutírico, málico, glicólico, mandélico e tartárico, nos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: PHB (poly 3-hydroxybutyrate) homopolymer is an important biocompatible and biodegradable material, however when it is processed using the typical extrusion and injection rheological techniques the PHB is thermally unstable and thus the obtained materials have limited mechanical properties. Considering the monomer in the PHB chain, the 3-hydroxybutyric acid it has been proposed to study the interaction with malic, glycolic, tartaric and mandelic acid with PHB. Those hydroxyacids have hydroxyl and carboxyl functional groups in their structures, so it was expected some physical and chemical interactions. The hydroxyacids production is based on natural process and then a new polymeric material will maintain the same properties of biodegradability and biocompatibility presented by PHB4V% (poly 3-hydroxybutyrate containing 4% of 3-hydroxyvalerate monomer), nevertheless with better potential for its applications. The thermal behavior study, using the TG-DTA and DSC techniques were important to define which of the sample films showed lower melting point, glass transition and on the other hand higher crystallization temperature with higher thermal stability. From the kinetic study we determined the Arrhenius's ... (Complete abstract click electronic access below) / Doutor

Neste trabalho, investigamos o microambiente da amilopectina na ausência e presença de tensoativos não-iônicos como o éter dodecil (7 e 23)-polioxietilênico (Unitol L-70 e L-230) e o nonilfenol (9,5)-polioxietilênico (Renex 95), por meio das propriedades físico-químicas de sondas de polaridade: pireno, xantona e Reichardt. Os estudos foram realizados através de técnicas espectroscópicas em estado estacionário (absorção de luz ultravioleta-visível e fluorescência) e resolvidas no tempo (baseadas na contagem de fótons únicos da emissão de fluorescência e na absorção triplete-triplete (T-T) e de intermediários reativos formados após a fotólise da amostra por pulso de laser). Estas técnicas forneceram os valores de: concentração de agregação crítica (cac), concentração micelar crítica (cmc), número de agregação (Nag) e polaridade (escala py e ET30) para os sistemas avaliados. Os dados obtidos foram comparados com as soluções contendo a presença ou não dos tensoativos não-iônicos e a carboximetil celulose (CMC) e 2-hidroxietilamido (2-HEAM). Por fim, a estabilidade do cátion 2-fenilbenzopirílio foi avaliada em diferentes solventes orgânicos, nas micelas dos tensoativos estudados, nos biopolímeros e nos complexos biopolímero-tensoativo. Dois procedimentos experimentais diferentes foram adotados para o preparo das soluções de amilopectina. As diferenças na preparação das soluções de amilopectina tornaram evidente que este biopolímero possui diferentes ambientes para a localização das sondas. Estas diferenças não foram observadas na presença de CMC e de 2-HEAM. Os resultados experimentais confirmaram a interação cooperativa entre a amilopectina e os tensoativos Unitol L-70 e L-230. Esta interação é menos pronunciada para os sistemas formados entre os tensoativos e 2-HEAM e desfavorecidos na presença de CMC. Nos experimentos onde foi avaliado o equilíbrio monômero-excímero do pireno, verificou-se que os complexos amilopectina-tensoativo agrupam um número maior de moléculas de pireno do que os clusters de amilopectina sozinhos. Estes ambientes favoreceram ambos os movimentos de rotação e translação entre as moléculas, para a formação do excímero. Os estudos resolvidos no tempo, utilizando a xantona como sonda fotofísica para as técnicas de fluorescência resolvida no tempo ou de fotólise por pulso de laser, demonstraram que na amilopectina, a sonda ocupa preferencialmente o ambiente aquoso, ao invés dos microambientes internos do polímero. Isto possivelmente é uma decorrência da proteção das cadeias ramificadas do seu esqueleto polimérico. Estes mesmos estudos indicaram que na presença de concentrações mais elevadas de CMC, a xantona migra do seio da solução aquosa para ambientes próximos à cadeia polimérica onde podem ocorrer sua protonação ou associação em sítios não protonados. Em relação à estabilização do cátion 2-fenilbenzopirílio, nas condições estudadas envolvendo tanto os biopolímeros quanto os sistemas biopolímero tensoativo, predominaram os isômeros da chalcona. Os maiores tempos de meia-vida foram observados em CMC, o que pode ser justificado pela maior viscosidade do meio. / In this work, the amylopectin microenvironment was studied in the presence and absence of the non-ionic surfactants polyoxyethylene (7 and 23) dodecyl ether (Unitol L-70, and L-230, respectively) and polyoxytethylene (9.5) nonylphenol ether (Renex 95), through the physical-chemical properties of the polarity probes: pyrene, xanthone, and Reichardt. Steady-state (UV-visible absorption, and fluorescence), and time-resolved (time-correlated single photon counting fluorometry, and laser flash photolysis) techniques were used to evaluate the critical aggregation concentration (cac), critical micellar concentration (cmc), average micellar aggregation numbers (Nag), and polarity (py, and ET30 scales) of the complexes of amylopectinnon-ionic surfactants. The amylopectin experimental results were compared with the obtained ones from aqueous solutions of carboxymethyl cellulose (CMC) and 2-hydroxyethyl starch (2-HEAM) in the absence and presence of nonionic surfactants. The stability of 2-phenylbenzopyrilium cation was also investigated in several organic solvents, in the non-ionic surfactant micelles, in the biopolymers and in the complexes of biopolymer-surfactants. The amylopectin aqueous solutions were prepared by two different experimental procedures. The determined results of the relative intensities of pyrene fluorescence emission bands 1 to 3, and excimer and monomer ratio have pointed out that the amylopectin presents different microenvironments for photophysical probes relocation. Such differences were not observed in the presence of CMC and 2-HEAM. The cooperative interaction between the amylopectin, and the Unitol-L70 and L- 230 surfactants were comproved by the experimental results. The complexes of 2- HEAMnon-ionic surfactant were less stable than the amylopectin ones, while CMC does not form complexes of biopolymer-surfactants. The single-photon timing and laser flash photolysis techniques employing xanthone as probe have shown that this probe remains at the aqueous bulk of the amylopectin solutions. There is no interaction between xanthone and the amylopectin backbone, probably due to the great extent of the polymeric branching. On the other hand, in presence of higher concentrations of CMC solutions, xanthone can relocate from the aqueous solution to the polymeric microenvironment, where the probe can be or not protonated. The evaluation of the stability of 2-phenylbenzopyrilium cation in the presence of biopolymer or complexes of biopolymer-surfactants has shown the predominance of the chalcone isomers. The higher half-life times were determined in the CMC because of the higher viscosity of the medium.

The study of the processes relating glycobiology and cancer will have increased interest in coming years. To contribute to this trend the outcome of this work will be useful for investigations in glycobiology, using experimental methods exhibiting controlled carbohydrate composition, organization, and orientation, drawn from materials science and physics and that can be used in bioengineering and other technical areas in biology. In this work, the focus has been on physical studies of some members of the family of glycosaminoglycans and their role in cancer metastasis. The project studies the static adhesion of cancer cells to substrates functionalized with cell surface glycocalyx molecules and, in particular, in the interaction of heparan sulfate, keratan sulfate and chondroitin sulfates with the cells. Surface characterization techniques are used to analyze the structure of the polymeric brushes deposited on the substrates. The hypothesis that the adhesion of whole cancer cells to glysocaminoglycan substrates is a function of polysaccharide charge per dimer and chain length was proposed and tested.Part of the work has been dedicated to study the changes in the adhesion of tumor cells inthe presence of heparanase, an enzyme expressed in the tumor cell surface.The essential achievements of the project have been: a) Design of a new a method for the deposition and patterning of glycans to glass or silicon surfaces functionalized with a silane agent, exposing an amino terminated monolayer as functional substrate. b) Development of a new method for the calculation of the density of the deposited molecules. c) Physical characterization of the surfaces using a combination of surface science techniques, including ellipsometry and atomic force microscopy. These surfaces should be useful for developing additional experiments that may be helpful in understanding the adhesive properties of the cells. d) Comparative analysis of the behavior of cancer cells to the functionalized surfaces, specifically the study of the static adhesion of the cells, in the presence or absence of the surface protein heparanase or its inhibitors. e) Confirmation of the hypothesis that attachment of whole cancer cells, in vitro, depends linearly on the charge per dimer of polysaccharide.

No description available.

A PHA producing bacterium (strain QN271) was selected from mangrove soil samples collected from Quang Ninh province by using the Nile red dying technique. PHA accumulation in the selected bacterium strain was confirmed by transmission electron microscope. With the exception of maltose or sucrose, the bacterium strain was found to be able to synthesize PHA from various carbon sources (glucose, xylose, fructose, glycerol, and glucose plus propionate). The strain accumulated poly(3-hydroxybutyrate) from glucose, fructose, xylose, and glycerol whereas poly(3-hydroxybutyrate-co-3-hydroxyvalarate) was produced when a combination of glucose and propionate was included in the culture medium. Fructose was found to be most suitable substrate for PHA synthesis by strain QN271. PHA content of 63.3% and CDW of 6 g/L were obtained after 32 hrs of cultivation in fructose medium. / Chủng vi khuẩn có khả năng sinh tổng hợp PHA đã được phân lập từ đất rừng ngập mặn tỉnh Quảng Ninh nhờ kỹ thuật nhuộm với Nile red. Ảnh quan sát dưới kính hiển vi điện tử dẫn truyền chứng tỏ rằng chủng vi khuẩn này có khả năng tích lũy lượng lớn PHA trong tế bào. Chủng vi khuẩn tuyển chọn có khả năng sinh tổng hợp PHA từ nhiều nguồn các bon khác nhau như glucose, xylose, fructose, glucerol, glucose và propionate nhưng không có khả năng tổng hợp PHA từ maltose hoặc saccharose. Chủng vi khuẩn tuyển chọn tổng hợp poly (3-hydroxybutyrate) từ các nguồn các-bon như glucose, xylose, fructose, hay glycerol, trong khi đó poly (3-hydroxybutyrateco- 3-hydroxyvalarate) sẽ được tổng hợp khi phối hợp sử dụng hai nguồn các-bon (glucose và propionate). Fructose là nguồn các-bon tốt nhất cho chủng QN271 sinh tổng hợp PHA, khi nuôi cấy trong môi trường có fructose chủng vi khuẩn này có thể tạo ra lượng sinh khối là 6 g/L trong đó có chứa 63.3% PHA sau 32 giờ.

No description available.