Artigos
URI permanente para esta coleçãohttps://repositorio.fei.edu.br/handle/FEI/800
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- Pretreatment of Guinea grass (Panicum maximum) with the ionic liquid 1-ethyl-3-methyl imidazolium acetate for efficient hydrolysis and bioethanol production(2018) Odorico F.H.; Morandim-Giannetti A.A.; Lucarini A.C.; Torres R.B.© 2018, Springer Science+Business Media B.V., part of Springer Nature.In the present study, we pretreated the plant Guinea grass (Panicum maximum) with the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate [EMIM][OAc] to expose its cellulose fibers. For this, we first determined the composition of Guinea grass, with 6.87 ± 1.21% of ash, 14.33 ± 1.18% of lignin, 70.55 ± 1.15% of holocellulose, 29.9 ± 1.20% of cellulose, and 40.65 ± 1.20% of hemicellulose. After characterizing the material, we determined the IL pretreatment conditions that maximized the enzymatic and acid hydrolysis stages [namely: temperature = 157 °C, reaction time = 30 min, and biomass concentration (relative to total mass) = 14%]. Under these conditions, the enzymatic hydrolysis conversions of glucose and total reducing sugars were respectively 69.8 and 54.2%, determined by enzymatic and DNS methods. The acid hydrolysis was also carried out, and conversions of 57.4 and 27.2% were verified by the enzymatic and DNS methods, respectively. Finally, the hydrolysate obtained after the enzymatic hydrolysis was fermented by the yeast Saccharomyces cerevisiae, and the ethanol yield (81.9%) was determined through gas chromatography.
- Synthesis and characterization of new low-cost ILs based on butylammonium cation and application to lignocellulose hydrolysis(2016) De Andrade Neto J.C.; De Souza Cabral A.; De Oliveira L.R.D.; Torres R.B.; Morandim-Giannetti A.D.A.© 2016 Elsevier Ltd. All rights reserved.Fourteen ionic liquids (ILs) were obtained and characterized by nuclear magnetic resonance and infra-red spectroscopy. One of these liquids, n-butylammonium acetate, was used in the treatment of coir fiber prior to acid hydrolysis. For this purpose, the fiber was pulped with 8% (w/w) sodium hydroxide for 6 h under 2.5 atm pressure at 137 °C and then treated with IL for 2 h at 90 °C. The samples were hydrolyzed in acetic acid at different concentrations and temperatures. The reducing sugar concentrations were determined in all samples, and the optimal hydrolysis conditions were established (32.2% acetic acid at 122.4 °C). The reaction time was also studied, and the conversion was maximized at 3 h. Under the best hydrolysis conditions, crude fiber, pulping fiber, and IL-treated fiber were hydrolyzed to yield 8.53%, 47.58%, and 89.75% of reducing sugars, respectively.