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Previous issue date: 2014-04-23 / O presente trabalho investigou o potencial de diferentes materiais lignocelul?sicos
residuais gerados em regi?es rurais e urbanas (fibra de coco maduro, casca de coco
verde e casca de coco maduro), al?m de vegetal cultivado em ambientes in?spitos
(cacto) visando ? produ??o de etanol, sendo todos, materiais abundantes na regi?o
Nordeste do Brasil. Esses materiais foram submetidos aos pr?-tratamentos com
per?xido hidrog?nio alcalino seguido por hidr?xido de s?dio (PHA-PHS), autohidr?lise
(PA), hidrot?rmico catalisado com hidr?xido de s?dio (PHCHS) e organosolv usando
etanol alcalino (POEA). Os materiais pr?-tratados foram submetidos ? hidr?lise
enzim?tica e as estrat?gias de fermenta??o e sacarifica??o simult?nea (SSF) e
fermenta??o e sacarifica??o semi-simult?nea (SSSF), utilizando-se Saccharomyces
cerevisiae, Pichia stipitis e Zymomonas mobilis. Avaliou-se tamb?m, a presen?a de
compostos inibit?rios (hidroximetilfurfural, furfural, ?cido ac?tico, ?cido f?rmico e ?cido
levul?nico) e a ?gua marinha no meio de cultivo. Os materiais pr?-tratados por PHAPHS
resultaram na deslignifica??o dos materiais em uma faixa entre 54,0 e 71,0%,
contendo entre 51,80 e 54,91% de celulose, entre 17,65 e 28,36% de hemicelulose,
entre 7,99 e 10,12% de lignina. As hidr?lises enzim?ticas proporcionaram convers?es
dos materiais em glicose entre 68,0 e 76,0%. Os rendimentos em etanol utilizando
SSF e SSSF para a fibra de coco maduro pr?-tratada variaram entre 0,40 e 0,43 g/g,
0,43 e 0,45 g/g, respectivamente. Os materiais pr?-tratados por PA apresentaram
rendimentos de s?lidos entre 42,92 e 92,74%, contendo entre 30,65 e 51,61% de
celulose e entre 21,34 a 41,28% de lignina. As hidr?lises enzim?ticas resultaram nas
convers?es dos materiais em glicose entre 84,10 e 92,52%. Os rendimentos em etanol
utilizando casca de coco verde pr?-tratada e as estrat?gias SSF e SSSF foram entre
0,43 e 0,45 g/g. A fibra de coco maduro pr?-tratada por PHCHS apresentou
rendimentos de s?lidos entre 21,64 e 60,52%, com aumento de celulose entre 28,40 e
131,20%, redu??o de hemicelulose entre 43,22 e 69,04%, redu??o de lignina entre
8,27 e 89,13%. A hidr?lise enzim?tica resultou em convers?o do material em glicose
de 90,72%. Os rendimentos em etanol utilizando SSF e SSSF foram 0,43 e 0,46 g/g,
respectivamente. Os materiais pr?-tratados por POEA apresentaram redu??es de
s?lido entre 10,75 e 43,18%, aumento de celulose em at? 121,67%, redu??o de
hemicelulose em at? 77,09% e redu??o de lignina em at? 78,22%. As hidr?lises
enzim?ticas resultaram nas convers?es dos materiais em glicose entre 77,54 e
84,27%. Os rendimentos em etanol utilizando cacto pr?-tratado e as estrat?gias SSF e
SSSF foram entre 0,41 e 0,44 g/g, 0,43 e 0,46 g/g, respectivamente. As fermenta??es
alco?licas realizadas em biorreator resultaram em rendimentos e produ??o de etanol
entre 0,42 e 0,46 g/g, 7,62 e 12,42 g/L, respectivamente. Os compostos inibit?rios
apresentaram efeitos sin?rgicos negativos nas fermenta??es realizadas por P. stipitis,
Z. mobilis e S. cerevisiae. O ?cido f?rmico e o ?cido ac?tico apresentaram efeitos mais
significativos entre os compostos inibit?rios, seguido pelo hidroximetilfurfural, furfural e
?cido levul?nico. As fermenta??es realizadas em meio de cultivo dilu?do com ?gua
marinha apresentaram resultados promissores, especialmente quando se utilizou S.
cerevisiae (0,50 g/g) e Z. mobilis (0,49 g/g). Os diversos resultados obtidos no
presente trabalho indicam que, os materiais lignocelul?sicos, pr?-tratamentos,
estrat?gias fermentativas e micro-organismos estudados merecem aten??o por
parecerem promissores e pass?veis de serem utilizados no contexto de biorrefinaria
visando ? produ??o de etanol. / The present work investigated the potential of different residual lignocellulosic materials
generated in rural and urban areas (coconut fibre mature, green coconut shell and
mature coconut shell), and vegetable cultivated in inhospitable environments (cactus)
aimed at the production of ethanol, being all materials abundant in the Northeast region
of Brazil. These materials were submitted to pretreatments with alkaline hydrogen
peroxide followed by sodium hydroxide (AHP-SHP), autohydrolysis (AP), hydrothermal
catalyzed with sodium hydroxide (HCSHP) and alkali ethanol organosolv (AEOP).
These materials pretreated were submitted to enzymatic hydrolysis and strategies of
simultaneous saccharification and fermentation (SSF) and saccharification and
fermentation semi-simultaneous (SSSF) by Saccharomyces cerevisiae, Zymomonas
mobilis and Pichia stipitis. It was also evaluated the presence of inhibitory compounds
(hydroxymethylfurfural, furfural, acetic acid, formic acid and levulinic acid) and
seawater during the fermentative process. Materials pretreated with AHP-SHP have
resulted in delignification of the materials in a range between 54 and 71%, containing
between 51.80 and 54.91% of cellulose, between 17.65 and 28.36% of hemicellulose,
between 7.99 and 10.12% of lignin. Enzymatic hydrolysis resulted in the conversions in
glucose between 68 and 76%. Conversion yields in ethanol using SSF and SSSF for
coconut fibre mature pretreated ranged from 0.40 and 0.43 g/g, 0.43 and 0.45 g/g,
respectively. Materials pretreated by AP showed yields of solids between 42.92 and
92.74%, containing between 30.65 and 51.61% of cellulose, 21.34 and 41.28% of
lignin. Enzymatic hydrolysis resulted in glucose conversions between 84.10 and
92.52%. Proceeds from conversion into ethanol using green coconut shell pretreated,
in strategy SSF and SSSF, were between 0.43 and 0.45 g/g. Coconut fibre mature
pretreated by HCSHP presented solids yields between 21.64 and 60.52%, with
increased in cellulose between 28.40 and 131.20%, reduction of hemicellulose
between 43.22 and 69.04% and reduction in lignin between 8.27 and 89.13%.
Enzymatic hydrolysis resulted in the conversion in glucose of 90.72%. Ethanol yields
using the SSF and SSSF were 0.43 and 0.46 g/g, respectively. Materials pretreated by
AEOP showed solid reductions between 10.75 and 43.18%, cellulose increase up to
121.67%, hemicellulose reduction up to 77.09% and lignin reduced up to 78.22%.
Enzymatic hydrolysis resulted in the conversion of glucose between 77.54 and 84.27%.
Yields conversion into ethanol using the SSF and SSSF with cactus pretreated ranged
from 0.41 and 0.44 g/g, 0.43 and 0.46 g/g, respectively. Fermentations carried out in
bioreactors resulted in yields and ethanol production form 0.42 and 0.46 g/g and 7.62
and 12.42 g/L, respectively. The inhibitory compounds showed negative synergistic
effects in fermentations performed by P. stipitis, Z. mobilis and S. cerevisiae. Formic
acid and acetic acid showed most significant effects among the inhibitory compounds,
followed by hydroxymethylfurfural, furfural and levulinic acid. Fermentations carried out
in culture medium diluted with seawater showed promising results, especially for S.
cerevisiae (0.50 g/g) and Z. mobilis (0.49 g/g). The different results obtained in this
study indicate that lignocellulosic materials, pretreatments, fermentative processes
strategies and the microorganisms studied deserve attention because they are
promising and capable of being used in the context of biorefinery, aiming the ethanol
production.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19289 |
| Date | 23 April 2014 |
| Creators | Gon?alves, Fabiano Avelino |
| Contributors | 10847022404, http://lattes.cnpq.br/3324083094904117, Assis, Cristiane Fernandes de, 03143301600, http://lattes.cnpq.br/0034694007210837, Oliveira, Jackson Araujo de, 65331060587, http://lattes.cnpq.br/5058617634570704, Porto, Ana L?cia Figueiredo, 25514776468, http://lattes.cnpq.br/4989617783837981, Rocha, Maria Valderez Ponte, 64669335391, http://lattes.cnpq.br/0639546287060338, Teixeira, Jos? Antonio Couto, Macedo, Gorete Ribeiro de |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM BIOTECNOLOGIA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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