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Recebido em 26/4/11; aceito em 11/11/11; publicado na web em 13/1/12 POTENTIAL OF SUGARCANE STRAW FOR ETHANOL PRODUCTION. Sugarcane straw biomass accounts for 1/3 of the energy potential of sugarcane and represents a rich source of sugars. Studies have been intensified for the use of this biomass along with bagasse for the production of cellulosic ethanol. Development of this technological path will allow for taking full advantage of sugarcane, increasing ethanol production without expanding the area cultivated. However, in order for this technology to be viable certain challenges must be overcome, including establishment of appropriate conditions of pretreatment and hydrolysis of these materials for release of fermentable sugars.Keywords: sugarcane straw; lignocelullosic biomass; ethanol. INTRODUÇÃOA iminente escassez das reservas de petróleo, principal fonte energética mundial, juntamente com as preocupações da sociedade com a preservação ambiental, são os principais motivos que levaram os governos a buscarem estratégias para uma maior produção e maior consumo de combustíveis que sejam renováveis e sustentáveis. 1,2 Um dos principais objetivos do uso dos biocombustíveis é a substituição de combustíveis fósseis, permitindo a diminuição da dependência por recursos não renováveis e a redução das emissões de gases de efeito estufa. A queima de combustíveis fósseis representa aproximadamente 82% das emissões dos gases causadores do efeito estufa. 3 Portanto, seja pela questão ambiental global, seja pela importância em reduzir a dependência externa de energia, o etanol de cana-de-açúcar, que já apresenta indicadores ambientais muito positivos quando comparado a outras opções, representa uma alternativa viável na substituição de combustíveis fósseis. 4 O etanol obtido do caldo de cana-de-açúcar (etanol de primeira geração) é, até o momento, o único combustível com capacidade de atender à crescente demanda mundial por energia renovável de baixo custo e de baixo poder poluente. Deve-se considerar que as emissões gasosas com a queima do etanol são da ordem de 60% menores se comparadas às emissões da queima da gasolina, sendo ainda que o do CO 2 emitido é reabsorvido pela própria cana. 5 Atualmente, o etanol é produzido praticamente a partir de matérias-primas sacarinas ou amiláceas, cana-de-açúcar e milho, respectivamente. Entretanto, há um grande esforço da comunidade científica para o desenvolvimento de novos processos economicamente viáveis para o aproveitamento da componente lignocelulósica da biomassa, caso dos resíduos agrícolas (palha e bagaço de cana-de--açúcar, palha de trigo e resíduos de milho) e resíduos florestais (pó e restos de madeira), assim como o capim elefante para produção de etanol combustível (etanol de segunda geração). 6,7 O mais abundante recurso biológico renovável da terra é a biomassa lignocelulósica. 8 Estima-se que somente os EUA têm potencial para produzir mais de 1,3 bilhões de toneladas (base seca) de biomassa por ano. 9 Segundo Zhang, 10 um bilhão de toneladas de biomassa seca produz e...

This work was carried out to investigate the pulp composition of four mango cultivars (Haden, Tommy Atkins and Ubá) at the ripening stage in relation to three components with antioxidant potential (total phenolics, carotenoids and ascorbic acid). Total phenolic compound content was estimated by the Folin-Ciocalteu reagent and total carotenoid content by spectrophotometry at 450 nm. The contents of beta-carotene and total vitamin C (ascorbic acid and dehydroascorbic acid) were quantified by high performance liquid chromatography. Differences were found among the four mango cultivars in all the components analyzed. The content of phenolic compounds ranged from 48.40 (Haden) to 208.70 mg/100 g (Ubá); total carotenoid from 1.91 (Haden) to 2.63 mg/100 g (Palmer); beta-carotene from 661.27 (Palmer) to 2,220 microg/100 g (Ubá) and total ascorbic acid ranged from 9.79 (Tommy Atkins) to 77.71 mg/100 g (Ubá). These results corroborated previous information that mangoes are a good source of antioxidants in human diet.

This paper describes a new gas-chromatography with electron capture detection (GC-ECD) method for determination of some pyrethroids in milk samples. The extraction of the pyrethroids was carried out by liquid-liquid extraction with clean-up by precipitation at low temperature, without additional stages for removal of fat interferences. The method was efficient with recoveries of 93.0+/-0.1% for cipermethrin and 84.0+/-0.3% for deltamethrin. The quantification limits were 0.75 microg L(-1) for both pyrethroids. The method was simple, of easy execution, and used only small quantities of organic solvent. After optimization and validation, the method was used for the determination of residues of the pyrethroids cipermethrin and deltamethrin in milk and in lactea drink commercialized in Viçosa (MG, Brazil). Some samples presented contamination with deltamethrin at levels below the maximum contamination limits established by the FAO.

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Extracellular proteases are an important virulence factor for the nematophagous fungi Monacrosporium. The objective of this study was to optimize, purify, partially characterize, and to evaluate the nematicidal activity of the proteases produced by the nematophagous fungus Monacrosporium sinense (SF53) by solid-state fermentation. Wheat bran was used as substrate for protease production. The variables moisture, pH, incubation time, temperature, glucose, yeast extract, and the number of conidia were tested for their influences on protease production by SF53. To determine the optimal level of the selected variables the central composite design was applied. The crude extract obtained was purified in two steps, an ion exchange chromatography and a gel excision. SDS-PAGE and zymogram were performed for analysis of the purification process. Proteolytic activity was also tested at different pHs and temperatures. In the in vitro assay, the nematicidal activity of the three proteases was evaluated. pH and incubation time showed a significant effect (p<0.05) on production of protease. The highest value of activity was 38.0 (U/ml) under the conditions of pH 5.0 and incubation time of 211 h. SF53 produced three different proteases (Ms1, Ms2, and Ms3) which were directly purified from the zymogram. Ms1, Ms2, and Ms3 showed the following percentage of reduction (p<0.05) on the number of Panagrellus redivivus compared to control after 24 h: 76.8, 68.1, and 92.1%. This is the first report of the use of proteases of the isolate SF53 on a phytonematode, which may be a research tool in future works.