We carried out the physico-chemical characterization of Immobead 150, a hydrophobic support for the immobilization of lipases. Thermomyces lanuginosus lipase (TLL) was immobilized on Immobead 150 by multipoint covalent attachment (ImmTLL) and the morphological, textural, structural, thermal, and physico-chemical properties of the support, before and after enzyme immobilization, were investigated. Immobead 150 presents approximately 1,000 µmol of epoxy groups per gram of support, a high hydrophobicity, and good thermal stability. The spherical particles of Immobead 150 present average diameters of 155 µm, specific surface areas of 137 m2 g-1 and pore volumes of 0.37 cm3 g-1, showing pores in the region of the micro and meso sizes. The immobilization process of TLL (150 mg g-1) caused a decrease of the specific area and pore volumes, to 63 m2 g-1 and 0.25 cm3 g-1, respectively, as a result of coating of the support surface by the enzyme molecule. However, the immobilization process did not affect the morphology of the support. The obtained biocatalyst was effective for the syntheses of fatty acid ethyl esters (biodiesel), and of aroma esters, showing yields of 68 and 70%, respectively, similar to commercial preparations used as controls.

Thin films containing silver nanoparticles homogeneously dispersed, with narrow size distribution below 10 nm, were synthesized on flat glass surface, by using an ionic silsesquioxane as stabilizer and crosslinking agent. The films can be prepared without previous functionalization of substrate surfaces and without addition of other components. The films were heat treated up to 200 ºC and characterized by ultraviolet-visible, transmission electron microscopy, atomic force microscopy, thermogravimetric analysis and ellipsometry. The films were thermally stable when heated up to 200 ºC, presenting the same thickness, and maintaining both optical and morphological properties of silver nanoparticles. The antibacterial activity of the films, containing the silver nanoparticles, was evaluated against Staphylococcus aureus by using the film applicator coating method, showing an excellent performance even after the third cycle of sterilization.

No Brasil, uma grande quantidade de resíduos fibrosos de soja (Glycine max) são gerados no processo de produção de proteína de soja. Estes materiais, ricos em celulose e hemicelulose, podem ser usados como substratos para cultivos microbianos visando a produção de valiosos metabólitos e enzimas. Neste trabalho, estudou-se a produção de enzimas, utilizando estes resíduos, por bactérias isoladas da água e do solo da região amazônica. Cinco cepas, dentre 87 iniciais, foram selecionadas e crescidas em cultivo semi-sólido (CSS). Preparações obtidas do isolado BL 62, identificado como Bacillus subtilis, apresentaram a maior atividade específica para celulase, 1,08 UI/ mg de proteína, em 24 horas de cultivo. No que se refere às xilanases, preparações obtidas do isolado BL 53, também identificado como Bacillus subtilis, apresentaram a maior atividade específica para esta enzima, com um valor de 5,19 UI/ mg de proteína, em 72 horas de cultivo. Também foi demonstrada a produção simultânea de proteases, o que pode ser associado à perda das atividades de celulase e xilanase durante o cultivo. Os resultados indicam que os microrganismos selecionados e o processo de cultivo empregado utilizando resíduo da soja apresentam grande potencial biotecnológico.

In Brazil, a large amount of a fibrous residue is generated as result of soybean (Glycine max) protein production. This material, which is rich in hemicellulose and cellulose, can be used in solid state cultivations for the production of valuable metabolites and enzymes. In this work, we studied the bioconversion of this residue by bacteria strains isolated from water and soil collected in the Amazon region. Five strains among 87 isolated bacteria selected for their ability to produce either celullases or xylanases were cultivated on the aforementioned residue. From strain BL62, identified as Bacillus subtilis, it was obtained a preparation showing the highest specific cellulase activity, 1.08 UI/mg protein within 24 hours of growth. Concerning xylanase, the isolate BL53, also identified as Bacillus subtilis, showed the highest specific activity for this enzyme, 5.19 UI/mg protein within 72 hours of cultivation. It has also been observed the production of proteases that were associated with the loss of cellulase and xylanase activities. These results indicated that the selected microorganisms, and the cultivation process, have great biotechnological potential.