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The objective of this work was to test the Fenton reaction on pretreatment of elephant grass aiming the final results of cellulose increase and the delignification process. A subsequent study of the enzymatic hydrolysis of the pretreated elephant grass and the mathematical modeling of hydrolysis was performed. A Doehlert-type experimental design was used into the pretreatment stage, and the best result were obtained at the central point with an average of 53.80% of cellulose and 10.00% of lignin. The enzymatic hydrolysis of pre-treated grass with Fenton reaction was performed, with a commercial enzyme (Celluclast® 1.5L), where the best yield (17.39%) of reducing sugars was obtained with 20 g L-1 of enzyme in 72 h and higher productivity (2.51 g L-1 h-1) observed in 2 h. It was possible to adjust the proposed mathematical model to the hydrolysis process. It was observed that, for higher concentrations of enzyme, the proposed mathematical model adjusts better the experimental results (R2 = 0.974). It can be observed with these results, that there was an increment in the economic profitability of the enzymatic hydrolysis process due to the relation of the operational parameters, so that it can be used in new projects and industrial applications.

Na região oeste do Estado do Paraná, vem crescendo o interesse dos agricultores e empreendedores de usinas de bioenergia pelo aproveitamento do potencial de geração de biogás e biofertilizante com uso dos resíduos da atividade de suinocultura. Foram implantadas nessa região, usinas de bioenergia que fazem o processamento e aproveitamento dos dejetos de suínos. Nas granjas, os suinocultores utilizam os biofertizantes desses resíduos e de forma gradativa vem sendo implantado tecnologias para a utilização do biogás como fonte de bionergia. No estudo, abordou-se as principais metotologias para o aproveitamento desses resíduos, com fundamentação nos aspectos legais ambientais e referências doutrinárias dos sistemas mais utilizados nas granjas nessa região pelos suinocultores. Buscou-se demostrar as tecnologias implantadas, que foram validadas por instituição de pesquisas do setor e que são passíveis de integrar os processos de licenciamentos ambientais no Estado do Paraná. Dessas tecnologias, especifica-se o estudo da compostagem tradicional, a acelerada, a acoplada a um biodigestor e a com uso de desidratador, a esterqueira e o biodigestor. Estas, quando implantadas e manejadas adequadamente pelos suinocultores possibilitam a otimização dos custos de produção, agregam valores aos resíduos e consequentemente contribuem com a sustentabilidade da atividade de suinocultura. Estas tecnologias ainda que úteis e funcionais, podem ser aprimoradas para melhorar seus sistemas no aproveitamento de produção de bioenergia e biofertilizantes. Numa perspectiva futura, pesquisadores dessas tecnologias buscam esse aperfeiçoamento dos sistemas de processamento de resíduos visando diminuir os impactos negativos gerados pela atividade suinícola e o aproveitamento dos resíduos de forma sustentável.

International audience; Microalgae have been evaluated as a source of lipids for biodiesel production. They can be grown on effluent and produce biomass while removing organic and mineral components from the medium. The use of agro-industrial wastes for the production of microalgae is an alternative to reduce the costs related to the composition of the culture medium, thus reducing operational costs considerably. This work was conceived as a research about the cultivation of microalgae Scenedesmus acuminatus on the substrate composed by corn steep liquor. A central composite design (CCD) was carried to study the influence of the effluent and inoculum concentration on the chemical oxygen demand (COD) of the culture. Statistical analysis indicated that the percentage of inoculum and effluent had an influence on the COD. The cultivation, together with the coagulation procedure, was efficient for the removal of organic matter, verified through the COD reduction and changing of pH value. These two parameters reached the appropriate level according to the standard required by current legislation.

The increasing energy demand and reduction in the availability of nonrenewable energy sources, allied with an increase in public environmental awareness, have stimulated a search for alternative energy sources. The present study was aimed at producing biomass from the microalgaSpirulina platensisand at assessingin situsynthesis of alkyl esters via acid transesterification/esterification of biomass to produce biodiesel. Two alcohols (ethanol and methanol) and two cosolvents (hexane and chloroform) were tested, at different temperatures (30, 45, 60, 75, and 90°C) and reaction times (10, 20, 30, 60, and 120 min). The factorial analysis of variance detected an interaction between the factors (): temperature, reaction time, alcohol, and cosolvent. The best yields were obtained with the combination ethanol and chloroform at 60°C, after 30 min of reaction, and with hexane at 45°C, after 10 min of reaction.In situtransesterification/esterification of alga biomass to form esters for biodiesel production adds unconventional dynamics to the use of this feedstock.