Resumo: Formulações de aplicação não-poluente à base de poliuretanos em dispersão aquosa (WPUs), com adição de argila montmorilonita hidrofílica (CWPUs), foram sintetizadas. A permeabilidade ao dióxido de carbono (CO 2 ) de membranas densas obtidas a partir do espalhamento das dispersões foi avaliada. Os reagentes empregados na síntese dos materiais foram: poli(glicol proplilênico) (PPG), copolímero em bloco à base de segmentos de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG), ácido dimetilolpropiônico (DMPA), diisocianato de isoforona (IPDI) e etilenodiamina (EDA), como extensor de cadeia, levando à formação de ligações de ureia. Diferentes formulações foram obtidas variando-se a proporção de segmentos à base de poli(glicol etilênico) (PEG) e o teor de argila (0,5 e 1 %). As dispersões foram avaliadas em termos de teor de sólidos e viscosidade aparente. As membranas foram caracterizadas por espectrometria na região do infravermelho (FTIR) e permeabilidade ao dióxido de carbono (CO 2 ). A influência nas propriedades de barreira, conferida pela presença da argila e do copolímero em bloco, foi verificada por ensaios de permeabilidade. A permeabilidade ao CO 2 aumentou com o aumento no teor segmentos de PEG e diminuiu com a inserção da argila, uma vez que esta é impermeável a gases, formando caminhos preferenciais na matriz polimérica que retardam a difusão das moléculas de gás. Palavras-chave: Poliuretanos, dispersões aquosas, argila, montmorilonita, membranas, permeabilidade a gases, propriedades de barreira. Evaluation of Carbon Dioxide Gas Barrier Properties of Membranes Obtained from Aqueous Dispersions Based on Polyurethane and ClayAbstract: Non-polluting aqueous polyurethane-based dispersions were synthesized in the presence and absence of montmorillonite hydrophilic clay (WPUs and CWPUs, respectively). The permeability of carbon dioxide (CO 2 ) through dense membranes obtained from the dispersions was evaluated. The reagents used in the synthesis of the materials were: poly(propylene glycol) (PPG), block copolymer of poly(ethylene glycol) and poly(propylene glycol) (EG-b-PG), dimethylolpropionic acid (DMPA), isophorone diisocyanate (IPDI) and ethylene diamine (EDA) as chain extender, leading to the formation of urea linkages. The proportion of poly(ethylene glycol) (PEG) segments and clay content (0.5 and 1%) was varied in the formulations. The dispersions were evaluated in terms of solids content and apparent viscosity. The membranes were characterized by infrared spectrometry (FTIR) and permeability to carbon dioxide (CO 2 ). The influence on the gas barrier properties, imparted by different contents of PEG segments in polyurethane chains, and by the clay in the formulations was verified. The permeability of CO 2 increased with increasing amounts of PEG segments and decreased with the insertion of clay, since the latter is impermeable to gas and forms, in the polymeric matrix, tortuous pathways that retard gas diffusion.

O presente trabalho estuda o processo de produção de ácido lático a partir de biomassa lignocelulósica. Com auxílio do software Microsoft Excel, foi realizado o balanço material a fim de se obter o rendimento global do processo. Foi realizado estudo de cenários alternativos para avaliar o impacto do rendimento da etapa de hidrólise enzimática no rendimento global e parcial (considerando apenas a fração celulósica) em ácido lático. O melhor rendimento em ácido lático a partir de bagaço de cana, quando só a fração celulósica da biomassa é considerada, equivale a 84,74%. Palavras-chave: ácido lático; balanço material; matéria-prima lignocelulósica.The present work studies the lactic acid production process based on lignocellulosic biomass. Material balance relative to the stages of production was made to calculate the global yield of the process. Scenario Manager was used to evaluate the impact of the enzymatic hydrolysis efficiency in the global yield. The best yield regarding only the cellulosic fraction of the biomass achieved using sugarcane bagasse as feedstock was 84.74%.

The combined effects of the processing parameters upon rheological properties of biopolymers produced by Rhizobium tropici were studied as a function of the Ca(+2) ions' concentration variation, yeast extract concentration added to the medium, aeration, and agitation, maintaining the mannitol concentration in 10 g/L. The experiments were carried out using a fermenter with 20-L capacity as a reactor. All processing parameters were monitored online. The temperature [(30 +/- 1) degrees C] and pH values (7.0) were kept constant throughout the experimental time. As a statistical tool, a complete 2(3) factorial design with central point and response surface was used to investigate the interactions between relevant variables of the fermentation process: calcium carbonate concentration, yeast extract concentration, aeration, and agitation. The processing parameter setup for reaching the maximum response for rheological propriety production was obtained when applying mannitol concentration of 10.0 g/L, calcium carbonate concentration 1.0 g/L, yeast extract concentration 1.0 g/L, aeration 1.30 vvm, and agitation 800 rpm. The viscosimetric investigation of polysaccharide solutions exposed their shear-thinning behavior and polyelectrolytic feature.

O trabalho estudou a cinética de biossorção do corante Acid Blue 324 pela cianobactéria Spirulina maxima. Avaliou-se a capacidade de remoção da cor do referido corante, o qual foi adicionado à cultura da cianobactéria Spirulina maxima. Foram avaliados dois fatores, a concentração de nitrato e a concentração de corante. O estudo demonstrou bons resultados na remoção do corante do meio de cultura com redução expressiva da cor, alcançando valores acima de 80% na remoção da cor na cultura. Palavras-chave: acid blue 324; Spirulina maxima; biossorção.The work studied the biosorption kinetics of the dye Acid Blue 324 by the cyanobacteria Spirulina maxima. It was evaluated the color removal capacity of the said Dye, which was added to the culture of the cyanobacteria Spirulina maxima. Two factors were evaluated, the concentration of nitrate and the concentration of dye. The study demonstrated good results in the removal of the dye from the culture medium with expressive reduction of the color, reaching values above 80% in the removal of the color in the culture.

In this study, the rheological behaviors of media fermented by two Aureobasidium pullulans strains (IOC 3467 and IOC 3011) were evaluated in different nutritional conditions. The media consisted of crystal sugar (sucrose), as the main carbon source, and different nitrogen sources (ammonium sulfate, sodium nitrate, ammonium nitrate, urea or residual brewery yeast -RBY). Viscosity measurements were performed on cell-free supernatants, from 48-hour fermentation assays, at 25 8 C. Shear rates ranged between 0.1000 and 500 s À1 . All samples showed pseudoplastic behavior. Nevertheless, the viscosimetric profile of each one varied according to the nitrogen source, its concentration and the strain used. The maximum viscosity of 0.06 Pa.s. was achieved at 15.6 s À1 for IOC 3011 strain grown on RBY as nitrogen source.