Banca de DEFESA: CLEITIANE DA COSTA NOGUEIRA
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : CLEITIANE DA COSTA NOGUEIRA
DATA : 07/02/2017
HORA: 14:30
LOCAL: AUDITÓRIO DO PPGEQ
TÍTULO:
"Evaluation of surfactants in dilute acid and alkaline pre-treatment of green coconut fiber and quantification of post-washing"
PALAVRAS-CHAVES:
coconut, pretreatment, surfactant, enzymatic hydrolysis, washing
PÁGINAS: 87
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Química
RESUMO:
Brazil is the fourth higher producer of coconut and approximately 85% of the total fruit mass are becoming residue that it could be converted into ethanol. However, the pretreatment of the biomass plays a key role in order to increase the accessibility as well as the biodegradability of cellulose and hemicellulose to facilitate the further saccharification step. Most pretreatments are able to produce inhibitors such as phenolic compounds and acids that must to be removed. Usually water has been used in the washing step but its use should be reduced in order to become the process viable both economically and environmentally. Also, studies are showing that surfactants can be used during the pretreatment aiming to achieve higher yields of fermentable sugars leading thus to higher ethanol production. In this context, in this study it was investigated the influence of the Tween 80 in the pretreatment of the green coconut fiber also it was assayed the use of the water in the washing step of the pretreated biomass. By means of experimental design it was investigated for both pretreatments using H2SO4 and NaOH the influence of chemical and surfactant concentration as well as the pretreatment time. The obtained biomass after washing suffered enzymatic hydrolysis (Celluclast® 1.5L, 50 oC, 150 rpm, 96h, 20 FPU/g, 20CBU/g, 10FXU/g) assaying the conversion of the produced fermentable sugars. The acidic pretreatment showed that both H2SO4 concentration and the pretreatment time were significant, showing the former a negative effect while the latter showed a positive one. The best hydrolysis result for this planning was of 6.86 g/L and 2.14 g/L for glucose e xylose, respectively, obtained for the run with H2SO4 and Tween 80 at 60 min. For the alkaline pretreatment both the NaOH and Tween 80 concentration were significant, at 95.0% significance level, in which the best result after hydrolysis produced 13.83 g/L glucose and 5.77 g/L xylose using 2.0% (m/v) NaOH, 3.0 % (m/m) Tween 80 at 10 min. The pretreated material showing the highest concentration of fermentable sugars was assayed both morphologically and physico-chemically at presence and absence of surfactant. The evaluation of the pretreated material washing showed the possibility of reducing up to 75% of initial water volume without hampering the final production. The use of Tween 80 in the alkaline pretreatment improved the conversion into glucose and xylose during the enzymatic hydrolysis of the pretreated biomass. However, it did not show any significant influence for the acidic pretreatment. Besides, it was observed that the quantity of water used at washing step can be significantly reduced then contributing to the lignocellulosic ethanol production.
MEMBROS DA BANCA:
Presidente - 1346198 - EVERALDO SILVINO DOS SANTOS
Externo à Instituição - FRANCISCO CANINDE DE SOUSA JUNIOR - UFRN
Interno - 347401 - GORETE RIBEIRO DE MACEDO
Externo à Instituição - RUTHINÉIA JÉSSICA ALVES DO NASCIMENTO - UFERSA