One of the consequences of industrial food production activities is the generation of high volumes of waste, whose disposal can be problematic, since it occupies large spaces, and when poorly managed can pose environmental and health risks for the population. The rice industry is an important activity and generates large quantities of waste. The main solid wastes generated in the rice production cycle include straw, husk, ash, bran and broken rice. As such, the aim of this article is to present a review of this cycle, the waste generated and the identification of opportunities to use them. Owing to impacts that can be minimised with the application of rice husk ash as a by-product, this work is focused on the recycling of the main wastes. In order to achieve that, we performed theoretical research about the rice production cycle and its wastes. The findings point to the existence of an environmentally suitable use for all wastes from the rice production cycle. As rice, bran and broken rice have their main use in the food industry, the other wastes are highly studied in order to find solutions instead of landfilling. Straw can be used for burning or animal feeding. The husk can be used for poultry farming, composting or burning. In the case of burning, it has been used as biomass to power reactors to generate thermal or electrical energy. This process generates rice husk ash, which shows potential to be used as a by-product in many different applications, but not yet consolidated.

The potential of chemically and thermally treated Saccharomyces cerevisiae as biosorbents for chromium (VI) was investigated in this work. The presence of this toxic metal in industrial effluents is harmful to the environment, so, it is important to develop environmental friendly methods for Cr(VI) removal from these effluents. Biosorption using microorganisms such as S. cerevisiae is a viable treatment option because this biomass is easily available as a residue of fermentation industries. In this study, the affecting variables on Cr(VI) biosorption were studied by constructing biosorption isotherms, using lyophilized yeast subjected to chemical and thermal treatments. S. cerevisiae was able to remove 99.66% of Cr(VI) from effluents by biosorption. The significant variables affecting biosorption were pH, initial Cr(VI) concentration, and contact time. The biosorption isotherms were represented by the Freundlich model for the untreated biomass, BET model for the chemically treated biomass, and Langmuir model for the heat-treated biomass. Thermal treatment increased the biosorption affinity of the biomass for chromium, while the chemical treatment facilitated the formation of a multilayer.

I, BR 285, km 171, CP 611, Brasil Recebido em 26/8/12; aceito em 5/2/13; publicado na web em 15/4/13 PRODUCTION OF BIOSURFACTANTS BY MICRORGANISMS ISOLATED FROM SOIL CONTAMINATED WITH DIESEL OIL. The aim of this work was to produce biosurfactants through submerged fermentation using microorganisms isolated from soil contaminated with diesel. Microorganisms were isolated, characterized by the production of biosurfactants, and used to study the influence of type, induction and concentration of ammonium sulfate as a nitrogen source in the culture medium. The microorganisms that showed best results, in terms of production of biosurfactants, were identified as being of the genus Pseudomonas and Bacillus. The biosurfactants produced proved capable of reducing the surface tension of the media to 39 mN/m and 34 mN/m, respectively. Higher biosurfactant production was obtained in the medium containing 1% soybean oil without ammonium sulfate.

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In life cycle assessment (LCA), environmental impacts are classified according to the methodology used. Several life cycle impact assessment (LCIA) methods are currently used, and the method selected and the particulars thereof may influence the results obtained. This study characterized the main LCIA methods used and the most relevant categories of environmental impact. In total, 87 articles were initially retrieved using relevant keywords. After screening, 11 articles were shown to address the topic of study and were reviewed. The results showed that CML is the most widely used method. The main environmental impact category was global warming potential followed by acidification. Studies using LCA depend on the confirmation of the efficacy of the methods in the effort to represent and assess impacts in different regions of the world.