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Avaliação da hidrólise enzimática do sabugo de milho pré-tratado com ácido diluído e surfactante para a obtenção de bioetanol
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kleingesinds, Eduardo Krebs |
| Copyright Year | 2017 |
| Abstract | KLEINGESINDS, E.K. Evaluation of enzymatic hydrolysis of pretreated corn cob with dilute acid and surfactant in getting bio-ethanol. 2017. 92 p. Dissertation (Master of Science) Escola de Engenharia de Lorena, Universidade de São Paulo, Lorena, São Paulo, 2017. The indiscriminate exploitation of fossil fuels has been warning of the near collapse of the energy supply. Alternative sources have been explored with the purpose of presenting themselves as fuels with the same potential, besides being inserted in a context of sustainable development. Brazil, by consolidating its position with a strong agroindustrial market and having a wide variety of agricultural units, has as a by-product a high amount of waste, such as corn cob. Thus, we seek to make feasible methodologies that make the exploitation of this source economically advantageous to obtain second generation ethanol (2G). New methodologies have proposed the use of surfactants as additives in both pretreatment and enzymatic hydrolysis of lignocellulosic materials. In this context, the present work aimed to study the enzymatic hydrolysis of diluted-acid pretreated corn cob in the presence of different concentrations of the Tween 80 surfactant in combination with the dosage of the Cellic CTec2 enzymatic complex to obtain a glucose rich hydrolysate to produce ethanol by the yeast Scheffersomyces stipitis CBS 6054 in SHF (Separate Hydrolysis and Fermentation) process. The experiments were conducted according to experimental design 2 with centered face and 3 repetitions at the central point. The variables studied were: concentration of surfactant in the pretreatment and in the enzymatic hydrolysis and dosage of the enzymatic complex. The results showed that the use of surfactant in the pretreatment with diluted sulfuric acid had a greater effect on the removal of lignin and hemicellulose when used at the concentration of 10% (w/w). In this condition, the cellulose content was decreased by 21.1% as compared with the amount presents in the diluted-acid corn cob pretreatment without surfactant. The greatest decrease in crystallinity (81.23%) was with the use of 10% of the surfactant. The response surface analysis allowed to determine the optimum conditions of the SHF process to obtain maximum glucose yield (between 80 and 90%), when the pre-treatment surfactant concentration increased from 0 to 10% (w/w) with a reduction in the enzyme dosage (25,50 FPU/g dry lignocellulosic material) at a higher level than the surfactant concentration in the enzymatic hydrolysis. In these experimental conditions, glucose yield (80.54%) and glucose concentration (61.98 g/L) in the reaction medium were favored concomitantly with xylose yield (70.66%). This yeast concomitantly fermented the sugars (glucose, xylose and cellobiose) to ethanol with high conversion factor (0.37 g/g) and volumetric productivity (1.02 gethanol/L.h). The maximum specific velocity of consumption of these sugars was favored in the following order: glucose, cellobiose and xylose. After this fermentation was obtained a material with a more porous and fragmented surface. This fact evidenced that the enzymatic complex acted efficiently breaking down the crystalline cellulose obtaining an amorphous material. It is hoped that this work had contributed to the development of an alternative technology to produce ethanol by Biotechnological route from the corn cob lignocellulosic fraction in order to mitigate the environmental impacts intrinsic to the process. |
| File Format | PDF HTM / HTML |
| DOI | 10.11606/D.97.2017.tde-02052017-111731 |
| Alternate Webpage(s) | https://teses.usp.br/teses/disponiveis/97/97132/tde-02052017-111731/publico/BID17002_C.pdf |
| Alternate Webpage(s) | https://doi.org/10.11606/D.97.2017.tde-02052017-111731 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
