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Currently, petroleum-derived plastics are widely used despite the disadvantage of their long degradation time. Natural polymers, however, can be used as alternatives to overcome this obstacle, particularly cornstarch. The tensile properties of cornstarch films can be improved by adding plant-derived nanofibers. Sisal (Agave sisalana), a very common low-cost species in Brazil, can be used to obtain plant nanofibers. The goal of this study was to obtain sisal nanofibers using low concentrations of sulfuric acid to produce thermoplastic starch nanocomposite films. The films were produced by a casting technique using commercial corn starch, glycerol, and sisal nanofibers, accomplished by acid hydrolysis. The effects of glycerol and sisal nanofiber content on the tensile mechanical properties of the nanocomposites were investigated. Transmission electron microscopy findings demonstrated that the lowest concentration of sulfuric acid produced fibers with nanometric dimensions related to the concentrations used. X-ray diffraction revealed that the untreated fibers and fibers subjected to acid hydrolysis exhibited a crystallinity index of 61.06 and 84.44%, respectively. When the glycerol and nanofiber contents were 28 and 1%, respectively, the tensile stress and elongation were 8.02 MPa and 3.4%. In general, nanocomposites reinforced with sisal nanofibers showed lower tensile stress and higher elongation than matrices without nanofibers did. These results were attributed to the inefficient dispersion of the nanofibers in the polymer matrix. Our findings demonstrate the potential of corn starch nanocomposite films in the packaging industry. [ABSTRACT FROM AUTHOR]

Brazil is one of the largest ethanol biofuel producers and exporters in the world and its production has increased steadily during the last three decades. The increasing efficiency of Brazilian ethanol plants has been evident due to the many technological contributions. As far as yeast is concerned, few publications are available regarding the industrial fermentation processes in Brazil. The present paper reports on a yeast selection program performed during the last 12 years aimed at selecting Saccharomyces cerevisiae strains suitable for fermentation of sugar cane substrates (cane juice and molasses) with cell recycle, as it is conducted in Brazilian bioethanol plants. As a result, some evidence is presented showing the positive impact of selected yeast strains in increasing ethanol yield and reducing production costs, due to their higher fermentation performance (high ethanol yield, reduced glycerol and foam formation, maintenance of high viability during recycling and very high implantation capability into industrial fermenters). Results also suggest that the great yeast biodiversity found in distillery environments could be an important source of strains. This is because during yeast cell recycling, selective pressure (an adaptive evolution) is imposed on cells, leading to strains with higher tolerance to the stressful conditions of the industrial fermentation. [ABSTRACT FROM AUTHOR]

The increasing production of biodiesel in Brazil also increases glycerin production, a co-product of this industry. The main component of glycerin, glycerol, is highly energetic and because of that, glycerin is already used as animal feed in many countries. The objective of this paper was to evaluate the chemical composition of glycerin produced by biodiesel plants in Brazil and discuss its potential utilization as animal feed. Forty one samples of glycerin from sixteen biodiesel plants, that together yield 85.1% of Brazilian biodiesel, were analyzed. Chromium, cadmium and lead were not detected in any studied sample. Only four plants, that together yield 36.8% of Brazilian glycerin, comply the glycerol and moisture content levels established by the Ministry of Agriculture, Livestock and Food Supply. Only one, responsible for 14.1% of Brazilian glycerin, delivers glycerin with the potential to be used as ruminant feed once it doesn't use animal fat to produce biodiesel. [ABSTRACT FROM AUTHOR]

Abstract: Increasing environmental concerns in recent years focused greater attention on the development of biodegradable materials. This paper presents the preparation of cassava starch based composites incorporating fibers from Brazilian green coconuts. These composites were prepared with different amounts of coir fibers by thermal molding using glycerol as plasticizer for the starch. The matrix and composites were given thermal treatment. Both the untreated and treated matrices and their composites were characterized for their tensile properties, while water uptake, swelling on immersion in water and moisture absorption on exposure to humidity were evaluated for both untreated and treated matrix and its composites. The tensile properties of cassava starch improved with both the incorporation of fibers and thermal treatment. Fractographic studies through scanning electron microscopy were used to explain the observed strength properties. Water uptake, swelling and moisture absorption of TPS showed decrease with the incorporation of fibers, which is due to better interfacial bonding between the matrix and fibers as well as the hindrance to absorption caused by the fibers. [Copyright &y& Elsevier]