ABSTRACT Sodium carboxymethyl cellulose (CMC) is a cellulosic salt obtained by the cellulose alkalinization and later etherification of the cellulosic alkali with excess organic solvent. CMC is used as a thickening agent, humectant, binder, and others. It is usually synthesized from vegetable cellulose or also by bacterial cellulose (BC). The objective of this study is to synthesize CMC using bacterial cellulose produced by kombucha scoby to value this residue, using 3 different organic solvents, isopropanol, butan-1-ol and pentan-1-ol. After the synthesis, the CMCs were characterized by yield, moisture content, substitution degree (DS), pH, viscosity, Fourier Transform Infrared spectroscopy (FTIR), x-ray diffractometry (XRD), and thermogravimetry and derivative thermogravimetry (TG/DTG). The results proved the CMC synthesis and presented a decrease of the degradation temperature, and crystallinity in comparison to pure BC. Finally, the CMC produced with isopropanol had the best results compared to the literature, presenting higher yield (197,62%), higher substitution degree (0,26 ± 0,05), higher viscosity (11,33 ± 0,48 cP) e minor crystallinity (32,45%). However, a study with more samples would be necessary to obtain more precise results about the better solvent. (CMC solvent agent humectant binder others BC . (BC) residue solvents butan1ol butanol butan 1 ol pentan1ol. pentan1ol pentanol pentan ol. pentan-1-ol content DS, DS , (DS) pH FTIR, FTIR (FTIR) xray x ray XRD, XRD (XRD) TG/DTG. TGDTG TG/DTG TG DTG (TG/DTG) temperature Finally literature 197,62%, 19762 197,62% 197 62 (197,62%) 0,26 026 0 26 (0,2 0,05, 005 0,05 05 0,05) 11,33 1133 11 33 (11,3 048 48 0,4 cP 32,45%. 3245 32,45% 32 45 (32,45%) However (BC (DS (FTIR (XRD (TG/DTG 1976 197,62 19 6 (197,62% 0,2 02 2 (0, 00 0,0 11,3 113 (11, 04 4 0, 324 32,45 (32,45% 197,6 (197,62 (0 11, (11 32,4 (32,45 197, (197,6 ( (1 32, (32,4 (197, (32, (197 (32 (19 (3

RESUMO A carboximetilcelulose de sódio (CMC) é um sal celulósico obtido por meio da alcalinização da celulose e posterior eterificação do álcali celulósico com excesso de solvente orgânico. A CMC é utilizada como agente espessante, umectante, aglutinante, entre outros. Comumente ela é sintetizada a partir da celulose vegetal ou também a partir de celulose bacteriana (CB). O objetivo deste estudo foi sintetizar a CMC utilizando CB produzida pelo scoby de kombucha, para valorizar esse resíduo, utilizando 3 diferentes solventes orgânicos, isopropanol, butan-1-ol e pentan-1-ol. Após a síntese, as CMCs foram caraterizadas por rendimento, teor de umidade, grau de substituição (GS), pH, viscosidade, espectroscopia no infravermelho com transformada de Fourier (FTIR), difratometria de raios-x (DRX), termogravimetria e termogravimetria derivada (TG/DTG). Os resultados comprovaram a síntese das CMCs e apresentaram diminuição da temperatura de degradação e da cristalinidade em comparação à CB pura. Por fim, a CMC produzida com isopropanol obteve melhores resultados em comparação à literatura, apresentado maior rendimento (197,62%), maior grau de substituição (0,26 ± 0,05), maior viscosidade (11,33 ± 0,48 cP) e menor cristalinidade (32,45%). No entanto, é necessário um estudo utilizando um número maior de amostras para que se obtenha resultados mais precisos acerca do melhor solvente. (CMC orgânico espessante umectante aglutinante outros CB. . (CB) kombucha resíduo orgânicos butan1ol butanol butan 1 ol pentan1ol. pentan1ol pentanol pentan ol. pentan-1-ol umidade GS, GS , (GS) pH FTIR, FTIR (FTIR) raiosx raios x DRX, DRX (DRX) TG/DTG. TGDTG TG/DTG TG DTG (TG/DTG) pura fim literatura 197,62%, 19762 197,62% 197 62 (197,62%) 0,26 026 0 26 (0,2 0,05, 005 0,05 05 0,05) 11,33 1133 11 33 (11,3 048 48 0,4 cP 32,45%. 3245 32,45% 32 45 (32,45%) entanto (CB (GS (FTIR (DRX (TG/DTG 1976 197,62 19 6 (197,62% 0,2 02 2 (0, 00 0,0 11,3 113 (11, 04 4 0, 324 32,45 (32,45% 197,6 (197,62 (0 11, (11 32,4 (32,45 197, (197,6 ( (1 32, (32,4 (197, (32, (197 (32 (19 (3

Abstract Bacterial cellulose (BC) is a biopolymer produced by several microorganisms and has attracted attention due to its unique characteristics, replacing cellulose extracted from nature. This work aimed to compare different BC production methods and the possible interference of these methods on the characteristics of the BC produced, seeking low-cost and large-scale production. BC membranes were produced by K. hansenii and a microbial consortium using different culture media. Rehydration percentage, water-holding capacity, TGA, and FTIR characterized the membranes. The production from the microbial consortium was highlighted for having a higher dry mass yield (0.289 ± 0.199 g), more than triple the amount produced by pure strain. Both samples showed similar chemical structures, as pointed out by FTIR. However, the BC produced by the microbial consortium showed superior thermal stability (357 °C). Moreover, using the microbial consortium, it was possible to obtain BC with a reduction in production cost of 92%. (BC nature lowcost low largescale large scale K media percentage waterholding water holding capacity TGA 0.289 0289 0 289 (0.28 0199 199 0.19 g, g , g) strain structures However 357 (35 °C. C °C . °C) Moreover 92 92% 0.28 028 28 (0.2 019 19 0.1 35 (3 9 0.2 02 2 (0. 01 1 0. 3 ( (0

Abstract Scaffolds with osteoconductivity, biocompatibility and good mechanical properties are promising for local drug release of sodium alendronate (ALN), a first-choice drug for treatment of bone tissue diseases, with low bioavailability. The viability to manufacture poly (L-lactic acid) (PLLA)/poly (methyl methacrylate) (PMMA) filaments containing ALN in different proportions, through extrusion, followed by scaffolds using 3D printing by fusion deposition modelling (FDM) and to investigate the influence of processes in mixtures drove this study. Differential scanning calorimetry (DSC), spectroscopy in the infrared region with Fourier transform (FTIR/ATR), and X-ray diffractometry (XRD) analysis indicated that PMMA decelerates crystallinity and confers malleability to PLLA/ALN mixture, besides its good processability and miscibility with PLLA and no relevant changes in physicochemical properties of components. Field emission scanning electron microscopy (SEM/FEG) showed good interfacial compatibility between PLLA/PMMA and homogeneously dispersed drug crystals in matrix. PLLA-PMMA-ALN scaffolds were manufactured by accurate with interesting properties for bone tissue engineering. osteoconductivity ALN, , (ALN) firstchoice first choice diseases bioavailability Llactic L lactic acid PLLA/poly PLLApoly /poly methyl methacrylate (PMMA proportions extrusion D FDM (FDM study DSC, DSC (DSC) FTIR/ATR, FTIRATR FTIR/ATR FTIR ATR (FTIR/ATR) Xray X ray XRD (XRD PLLAALN mixture components SEM/FEG SEMFEG SEM FEG (SEM/FEG PLLAPMMA matrix PLLAPMMAALN engineering (ALN (DSC (FTIR/ATR

ABSTRACT Bacterial cellulose (BC) has stood out in the biomedical field for its biocompatibility, non-toxicity and high liquid absorption capacity. Thus, studies have been conducted aiming at the functionalization of BC with substances that add properties, such as anti-inflammatory and antimicrobial action. Hamamelis virginiana plant extract is known for its astringent, anti-inflammatory and antimicrobial properties. Thus, the present work aimed to incorporate aqueous (AE) and glycolic (GE) extracts of witch hazel in different concentrations to BC, aiming at its application as a curative. BC membranes incorporated with the extracts were characterized by thermogravimetric analysis (TGA), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and antimicrobial activity. The TGA results indicated a reduction in thermal stability and the appearance of a new stage of degradation in the samples that underwent incorporation. Furthermore, the FTIR showed the presence of aromatic compounds not found in the BC, corroborating the TGA. The micrographs revealed that the incorporation of the extracts resulted in the formation of a film on the surface of the membranes, covering the nanofibers. These results show that incorporating the aqueous and glycol extracts in the BC membrane was successful. However, despite the crude extracts’ antimicrobial potential, antimicrobial activity in the functionalized BC samples was not observed. (BC biocompatibility nontoxicity non toxicity capacity Thus properties antiinflammatory anti inflammatory action astringent AE (AE GE (GE curative TGA, , (TGA) FTIR, (FTIR) SEM (SEM Furthermore nanofibers successful However potential observed (TGA (FTIR

Abstract Bacterial nanocellulose (BNC) membranes have interconnected porous nanostructures and excellent biocompatibility. Functionalizing these with calcium phosphate sources and metal ions confers optimized properties to the biomaterial. This study aims to synthesize BNC membranes, functionalize them with copper and magnesium apatites, characterize and evaluate their cytotoxicity and antimicrobial potential. Membranes were synthesized for 8 days in Mannitol Medium. The biocomposite production was by immersion cycles. The biocomposites were characterized by porosity and swelling capacity, Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), antimicrobial properties and cytotoxicity assays. The FTIR and SEM results showed that phosphate groups were incorporated into the BNC. The TGA analysis also indicated the incorporation of the inorganic phase. The membrane functionalization with Cu promoted the antimicrobial properties of the biomaterial. However, functionalization with Mg had a more positive behavior on cell viability, proving to be more suitable for use as an implantable material. (BNC biocompatibility biomaterial apatites potential Medium cycles capacity FTIR, , (FTIR) SEM, (SEM) TGA, (TGA) assays phase However viability material (FTIR (SEM (TGA

Abstract Bacterial cellulose (BC) is promising as a wound dressing because it is non- toxic and maintains moisture in the wound. Although BC does not have antimicrobial activity, its structure allows the incorporation of antimicrobial compounds such as essential oils (EOs). This study aims to associate BC with rosemary, clove, eucalyptus, ginger, lavender and lemongrass EOs to obtain wound dressings. The Gas Chromatography-Mass Spectrometry and Fourier Transform Infrared Spectroscopy analyses showed characteristic compounds of EOs in the incorporated membranes. These compounds reduced the thermal stability of most samples due to their different degrees of volatility. The Scanning Electron Microscopy indicated that the EOs filled the membrane pores and coated the cellulose fibers. Samples incorporated with clove, ginger and lemongrass EOs inhibited Escherichia coli, Staphylococcus aureus and Candida albicans due to the presence of eugenol and citral. The results confirmed the incorporation method's effectiveness, maintaining the composition and antimicrobial characteristics of the EOs. (BC non activity . (EOs) rosemary clove eucalyptus dressings ChromatographyMass Chromatography Mass membranes volatility fibers coli citral methods method s effectiveness (EOs

RESUMO Neste trabalho foi desenvolvido um biocompósito biodegradável a base de amido de banana verde (ABV) associado à celulose bacteriana (CB) e glicerina (GL), visando aplicação em produtos de rápida descartabilidade. Para a extração do amido, bananas verdes foram lavadas, cortadas e submersas em bissulfito de sódio a 1%, armazenadas em geladeira por 24 h, trituradas em liquidificador com água destilada e peneiradas. O amido precipitado foi disposto em placas de Petri e seco em estufa a 37 °C. Para avaliação da melhor composição com características hidrofóbicas e hidrofílicas, foi realizado um planejamento fatorial 23 completo com 3 pontos centrais, totalizando 11 amostras, sendo avaliada a influência da concentração de farelo de CB nos níveis 10 e 30 g/L, GL nas concentrações de 0 e 16 g/L e metiltrietoxisilano (MTES) na etapa de silanização nas concentrações de 0 e 4% em solução alcoólica. A análise de ângulo de contato permitiu identificar a hidrofobicidade das amostras comprovando a eficácia da silanização. Com base nas medidas de ângulo de contato das amostras foram produzidos os corpos de prova para caracterização contendo 20 g/L de CB, 8 g/L de GL e 4% de silano, uma vez que quanto maior concentração de silano, maior foi a hidrofobicidade do material. A análise de espectroscopia no infravermelho com transformada de Fourier (FTIR) apontou as bandas características de silano, comprovando a reação química com MTES, sendo também possível constatar a existência do amido, CB e GL. A análise termogravimétrica (TGA) demonstrou que a temperatura de degradação máxima da amostra ABV/FCB/GLcs silanizada (4%) se apresenta em Tmáx3= 310°C. Com o teste de degrabilidade em solo foi possível identificar que as amostras funcionalizadas demoram mais para degradar em comparação com as não silanizadas devido à sua barreira a umidade, característica que desacelera a degradação por microorganismos.

ABSTRACT In this work, a biodegradable biocomposite was developed, the green banana starch (GBS) associated with bacterial cellulose (BC) and glycerin (GL), aiming for application in rapid disposability products. For starch extraction, green bananas were washed, cut and submerged in 1% sodium bisulfite, stored in the refrigerator for 24 h, crumbled in a blender with distilled and sieved water. The precipitated starch was disposed of on Petri dishes and dried in an oven at 37°C. A complete factorial planning was carried out to evaluate the best composition with hydrophobic and hydrophilic characteristics with 3 central points, totaling 11 samples, the influence of BC bran concentration at levels 10 and 30 g/L, concentrations of 0 and 16 g/L and methyltriethoxisilane (MTES) in the silanization stage in concentrations of 0 and 4% in alcoholic solution. The contact angle analysis allowed identifying samples’ hydrophobicity, proving silanization effectiveness. Based on the contact angle measurements of the samples, the proof bodies for characterization were produced containing 20 g/L of BC, 8 g/L of GL and 4% silane since the higher concentration of silane, the greater material hydrophobicity. The infrared spectroscopy analysis with Fourier transform (FTIR) pointed out the silane characteristics bands, proving the chemical reaction with MTES, and it is also possible to see the existence of starch, BC and GL. Thermogravimetric analysis (TGA) demonstrated that the maximum degradation temperature of the sample GBS /FBC/GLcs silanized (4%) is Tmax3= 310 °C. With the soil degradability test, it was possible to identify that the functionalized samples take longer to degrade than those not silanized because of their barrier moisture, a characteristic that slows down microorganisms’ degradation.

RESUMO Polihidroxibutirato (PHB) é um biopolímero produzido intracelularmente e acumulado como reserva de energia por muitos microrganismos, sendo o principal, a bactéria Cupriavidus necator. Logo, é necessário realizar a extração dos grânulos intracelulares do interior das células. A extração química do PHB com clorofórmio e hipoclorito de sódio é eficiente, porém, utilizam-se elevadas quantidades de clorofórmio, solvente tóxico e volátil. Assim, faz-se necessário o estudo de novas tecnologias para a extração do PHB, buscando tornar o processo viável tecnologicamente, visto que este biopolímero é um importante candidato para substituição de polipropileno (PP). Diante desse contexto, este trabalho objetivou avaliar o processo de extração do PHB por meio das larvas de Zophobas morio Fabricius, comparado ao processo químico tradicional. O PHB foi sintetizado pela bactéria Cupriavidus necator em frascos de Erlenmeyer com 300 mL de meio mineral contendo glicose e frutose como fontes de carbono. O cultivo foi conduzido por 24 h a 30 °C e 150 rpm. A biomassa obtida do cultivo foi submetida à extração química (dispersão de clorofórmio/hipoclorito de sódio) e biológica, sendo, para isto, utilizada em uma mistura 2:1 (m/m) de farelo de trigo para biomassa úmida contendo PHB como fonte de alimentação das larvas de Zophobas morio Fabricius. O PHB obtido pelos dois processos foi caracterizado por termogravimetria (TG), calorimetria diferencial exploratória (DSC), espectroscopia na região do infravermelho com transformada de Fourier - reflexão total atenuada (FTIR/ATR), difratometria de raios-X (DRX) e microscopia eletrônica de varredura (MEV). Verificou-se que a amostra extraída pelo método biológico (PHB_EB), quando comparada com a amostra extraída pelo método químico (PHB_EQ), apresentou a mesma estrutura química e que a metodologia biológica usando larvas apresentou-se mais rápida e eficiente, garantindo a extração do PHB com elevada pureza e estabilidade térmica, com reduzida quantidade de solvente, tornando este processo mais ambientalmente amigável.

ABSTRACT Polyhydroxybutyrate (PHB) is an intracellularly produced biopolymer accumulated as an energy reserve by many microorganisms, being the main producer the bacterium Cupriavidus necator. Therefore, it is necessary to extract intracellular granules from the inside of cells. PHB chemical extraction with chloroform and sodium hypochlorite is efficient, but high amounts of chloroform, toxic and volatile solvent are used. Thus, it is necessary to study new technologies for the extraction of PHB, seeking to make the process technologically, since this biopolymer is an important candidate for polypropylene replacement (PP). In this context, this study aimed to evaluate the PHB extraction process from larvae Zophobas morio Fabricius. PHB was synthesized by the bacterium Cupriavidus necator in Erlenmeyer flascks with 300 mL of mineral medium containing glucose and fructose as carbon sources. The culture was conducted for 24 h at 30 °C and 150 rpm. Biomass obtained from cultive was submitted to chemical extraction (dispersion chloroform/sodium hypochlorite) and biological, and for this, used in a mixture 2:1 (m/m) of the wheat meal with cells containing PHB as a feeding source of the larvae of Zophobas morio Fabricius. PHB obtained by the two recovery processes were characterized by thermogravimetry (TG), exploratory differential calorimetry (DSC), infrared spectroscopy with Fourier transform - total attenuated reflection (FTIR/ATR), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). It was found that the sample extracted by the biological method (PHB_EB) , when compared with the sample extracted by the chemical method (PHB_EQ), presented the same chemical structure, and that the biological methodology using larvae was faster and more efficient, guaranteeing the extraction PHB with high purity and thermal stability, with reduced amount of solvent, making this process more environmentally friendly.

ABSTRACT This work aimed to obtain and characterize bacterial cellulose (BC) membranes obtained by cultivating Komagataeibacter hansenii ATCC 23769 using mannitol, glucose, fructose, lactose, glycerol, inulin, and sucrose as carbon sources, and corn steep liquor and Prodex Lac® as alternative sources of nitrogen. The formation of the BC´s gelatinous membrane was monitored for 12 days under static conditions and a temperature of 30 ºC. After purification, the membranes were dried and characterized by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The highest BC concentrations were found in the culture medium containing Prodex Lac® as the source of nitrogen. Among sugars, fructose and mannitol presented the best results. TGA analyzes indicate that all membranes have similar thermal behavior. The FTIR results show that the chemically synthesized membranes are equivalent to the structures cited in the literature. The micrographs obtained by SEM showed that the medium might influence BC´s morphology, but in general, all presented nanofibers, an essential feature in the membrane. Thus, the BC membranes synthesized in this study proved that the BC production using low-cost alternative means is feasible. The material obtained meets the expected thermal, physical, and chemical properties.

This study aimed at evaluating the effects of the incorporation of micro and nanoparticles of CaCO3 on the properties of poly(vinyl chloride) (PVC), intended to industrial application. The PVC compounds added with particles of different sizes were achieved in an intensive mixer. Rheological, microstructural, mechanical and thermal properties of the compounds obtained were evaluated. The rheology test showed that the compound with the addition of two-particle size plasticized faster compared than other formulations. Microstructural analysis showed a poor particle size distribution for the micro-CaCO3 charges, and the nano-CaCO3 samples have agglomerated particles. The thermal analysis showed the compound added with two particle size with higher gelation, and in the loss modulus E’ and E”, the values also were close. The analyses showed that the combination of the two-particle sizes presented superior results when compared with the micro or nano used singly.

This work aimed to synthesize bacterial cellulose (BC) membranes functionalized with Ce(NO3)3 and silver nanoparticles (AgNPs) heat-treated in oven and autoclave. The AgNPs were characterized by TEM and the membranes were characterized by their rehydration capacity, Thermogravimetric Analysis (TGA), Scanning Electron Microscopy with Dispersive Energy Spectroscopy (SEM/EDS), Wide-angle X-ray Diffractometry (XRD), Atomic Absorption Spectroscopy (AAS), antimicrobial activity and cytotoxicity. The BC membranes were white to light yellow or brown indicating functionalization with AgNps with 20 nm. XRD detected a decrease in the degree of crystallinity in functionalized membranes. The autoclaved samples exhibited the largest porosity and good rehydration capacity. AAS showed Ag presence in all samples. The best antibacterial activity was achieved for the membrane’s oven treated with 40 ppm of AgNPs. Among the functionalized membranes, the most recommended to be used as burn dressing is the Ag40A and Ag20CN1.1A since they showed good porosity, good antimicrobial activity, and better suitable cell viability.

ABSTRACT Glycerol was used as a source of additional carbon in the production of Poly(3-hydroxybutyrate) (P(3HB)). The inverted sugar and glycerol concentrations and the temperature of the Cupriavidus necator culture medium were evaluated using a Central Composite Rotational Design (CCRD). The results showed that the increase in temperature and sugar concentration led to an increase in production and P(3HB) accumulation and when 15 g L−1 of glycerol was added better results were obtained, however these were not considered statistically significant. The best results were obtained at 38 °C and with 30 g L−1 of inverted sugar. Although not considered statistically significant, the addition of 15 g L−1 of glycerol increased the P(3HB) accumulation percentage by 15 %, thus in kinetic terms, greater productivity was obtained in 0.32 g L−1 h−1 polymer. Larger scale assays are being conducted to verify if the addition of glycerol improves the thermal and mechanical properties of the synthesized polymer.

RESUMO A necessidade de reduzir a quantidade de resíduos plásticos descartada no meio ambiente revela a área de reciclagem como de grande interesse, tendo como uma das alternativas a reciclagem química do poli(tereftalato de etileno) (PET) pós-consumo com poliésteres alifáticos. Portanto, neste trabalho estudou-se a reação em massa do PET pós-consumo com o poli(L-ácido lático) (PLLA), plastificado com trietil citrato de sódio, visando obter novos copoliésteres alifático-aromáticos potencialmente biodegradáveis. A copolimeri zação foi conduzida em reator pela adição de PET (obtido de garrafas de refrigerante) e PLLA (obtido por uma reação de policondensação do L-ácido lático), variando de 10 a 90 % em massa. Em seguida, adicionaram-se os aditivos necessários e verteu-se em formas de silicone, obtendo os copolímeros. A técnica se mostrou adequada para a síntese de PET-co-PLLA, sendo esta confirmada através da análise de RMN 1H. As análises de TGA indicaram que a estabilidade térmica dos copolímeros aumenta conforme aumenta o teor de PET. Após a caracterização dos copolímeros, realizou-se o ensaio de biodegradação, a qual foi acompanhado por RMN 1H, FTIR-ATR, análise visual, MEV, DSC e TGA antes e após 15, 45 e 90 dias enterradas em solo preparado. Os resultados de biodegradação revelaram que a parte alifática dos copolímeros foi a primeira a sofrer biodegradação, indicando assim a preferência dos micro-organismos presentes no solo pelo PLLA. Estes resultados indicaram que é possível sintetizar novos copolímeros a partir de garrafas de refrigerante pós-consumo, potencialmente biodegradáveis quando descartados no meio-ambiente.

ABSTRACT The attempt to reduce the accumulation of plastic waste in the environment shows the recycling as an interesting area and the chemical recycling of poly(ethylene terephthalat) (PET) post-consumer allied to the reaction with aliphatic polyesters one of these methods to help solving this problem. Therefore, this work presents a study of bulk polymerization of PET post-consumer with poly(L-lactic acid) (PLLA), plasticized with sodium triethyl citrate, aiming to obtain new aliphatic-aromatics copolyesters potentially biodegradable. The copolymerization occurred in a glass reactor with N2 atmosphere. Different proportions were added of PET (obtained from soda packaging) and PLLA (obtained by a polycondensation reaction of L-lactic acid), among 10 and 90wt% and the temperature was gradually increased until melting. After that, the additives were added in the fluid mass which was shed in silicone molds. This method was adequate to synthesize copolymers of PET-co-PLLA and it could be confirmed through the 1H RMN analyses. The TGA analyses showed that the thermal stability increases with the raise of PET rate. After the characterization, the soil biodegradation was curried, which was accompanied by NMR 1H, FTIR-ATR visual analyses, SEM, DSC and TGA before and after buried in prepared soil. The results showed that the aliphatic fraction is the first to suffer scission of molecular chain, indicating a preference of the microorganisms from soil to PLLA and this method was adequate to synthesize new copolymers from soda packing post-consumer potentially biodegradable when discarded on environment.

Resumo Poli(3-hidroxibutirato) [P(3HB)] é um poliéster natural, biodegradável e é considerado um substituto atrativo para polímeros petroquímicos, pois tem a vantagem de ser degradado em solo dentro de alguns meses por micro-organismos. Este trabalho explora três estratégias para sintetizar P(3HB) a partir de Cupriavidus necator tendo glicerol como cosubstrato: cultivo sem glicerol, com adição de 20 g L–1 de glicerol na fase de produção do polímero e 20 g L–1 de glicerol no início do cultivo, a fim de avaliar o seu efeito sobre o crescimento celular e a síntese do polímero. Os resultados mostraram que a adição de glicerol no início do cultivo conduziu a maiores valores de percentagem de acúmulo de P(3HB) (64,12%). No entanto, nos experimentos sem glicerol podem ser observados maiores valores para fator de conversão em substrato (0,17 g g–1). Esses parâmetros apresentaram diferenças estatisticamente significativas em função da estratégia de cultivo utilizado.

Abstract Poly(3-hydroxybutyrate) [P(3HB)] is a natural, biodegradable polyester and is considered an attractive substitute for the petrochemical polymers, because has advantage of being degraded in the soil within a few months by microorganisms. This work exploits three strategies to synthesize P(3HB) from of the Cupriavidus necator with glycerol as co-substrate: cultivation without glycerol, with addition of 20 g L–1 glycerol in the phase of polymer producing and addition of 20 g L–1 of glycerol at the start of cultivation, in order to evaluate its effect on cell growth and the synthesis of the polymer. The results showed that the addition of glycerol at the start of culture led to highest values of accumulation percentage the P(3HB) (64.12%). However, in the experiments without glycerol can be observed higher values toward biomass to substrate yield (0.17 g g–1). These parameters presented statistically significant differences in function of the cultivation strategy used.

RESUMO Queimaduras causam lesões do revestimento epitelial, a partir de um agente externo, podendo variar desde uma pequena bolha flictena até formas mais graves, capazes de desencadear respostas sistêmicas. O uso de curativos contendo substâncias cicatrizantes e antimicrobianas é uma opção para terapia local. Os curativos de nanocelulose bacteriana (BNC) já demonstraram seu grande potencial de aplicação devido às suas propriedades como alto teor de pureza, alto poder de absorção de água e ótima adaptabilidade biológica. A incorporação de metais na membrana de nanocelulose é bastante promissora. Nanopartículas de prata (NPAgs) têm sido objeto de vários estudos devido às suas propriedades antibacterianas; nitrato de cério, Ce(NO3)3, por sua vez, aumenta a eficácia no tratamento por apresentar propriedades imunomoduladoras. O objetivo deste trabalho foi sintetizar e caracterizar membranas de nanocelulose bacteriana funcionalizadas com nitrato de cério e nanopartículas de prata visando aplicação no tratamento de pele humana lesionada por queimadura. O comportamento térmico, interações entre a BNC, Ce(NO3)3 e NPAg, bem como a morfologia, capacidade de retenção de água, reidratação e potencial antimicrobiano foram analisadas por termogravimentria (TGA), microscopia eletrônica de varredura (MEV), análise de conteúdo de capacidade de água, capacidade de reidratação e atividade antimicrobiana. A membrana formada pela incorporação de Ce(NO3)3 e NPAgs simultaneamente, e submetida ao tratamento térmico, conservou as propriedades térmicas de ambos os materiais, assim como também boa capacidade de reidratação e um potencial de redução microbiana de 98% para Staphylococcus aureus. A análise de MEV apresentou alteração na morfologia, redução de poros e a presença de partículas, o que sugere adequada incorporação dos compostos.

ABSTRACT Burns cause lesions of the epithelial lining, from an external agent, and can range from a small injury to more severe forms, capable of triggering systemic responses. The use of dressings containing healing and antimicrobial substances are options for local therapy. Bacterial nanocellulose (BNC) dressings have already demonstrated their great potential due to their properties such as high purity, high water absorption capacity and optimum biological adaptability. The incorporation of metals in the nanocellulose membrane is quite promising. Silver nanoparticles (AgNPs) have been studied because of their antibacterial properties; cerium nitrate, Ce(NO3)3, on the other hand, increases the efficacy of the treatment because of its immunomodulatory properties. The objective of this work was to synthesize and characterize bacterial nanocellulose membranes functionalized with cerium nitrate and silver nanoparticles aiming the treatment of human skin that has been subject to burning injuries. Thermal behavior, interactions between BNC, Ce(NO3)3 and AgNP, as well as morphology, water retention capacity, rehydration capacity and antimicrobial potential were analyzed by thermogravimetry (TGA), scanning electron microscopy (SEM), analysis of water content, rehydration capacity and antimicrobial activity. Membranes formed by incorporation of Ce(NO3)3 and AgNPs simultaneously, and submitted to heat treatment, preserved thermal properties of both materials, as well as a good rehydration capacity and a microbial reduction potential of 98% for Staphylococcus aureus. SEM analysis showed changes in morphology, pore size reduction and the presence of particles, what suggest successful incorporation of the compounds.