Influência do Tween 80 no pré-tratamento por explosão a vapor e alcalino, hidrólise enzimática e fermentação para produção de etanol a partir da fibra de coco verde
The green coconut fiber has been pointed out as an interesting alternative for the production of bioethanol, as Brazil is one of the largest global producers of the fruit and its disposal, generally inadequate, causes environmental problems. Pretreatments are necessary to remove compounds that pr...
Bewaard in:
| Hoofdauteur: | |
|---|---|
| Andere auteurs: | |
| Formaat: | doctoralThesis |
| Taal: | pt_BR |
| Gepubliceerd in: |
Universidade Federal do Rio Grande do Norte
|
| Onderwerpen: | |
| Online toegang: | https://repositorio.ufrn.br/handle/123456789/51951 |
| Tags: |
Voeg label toe
Geen labels, Wees de eerste die dit record labelt!
|
| Samenvatting: | The green coconut fiber has been pointed out as an interesting alternative for the production of
bioethanol, as Brazil is one of the largest global producers of the fruit and its disposal, generally
inadequate, causes environmental problems. Pretreatments are necessary to remove compounds
that protect cellulose from enzymatic attack, increasing the efficiency of enzymatic hydrolysis.
The addition of non-ionic surfactants in the bioethanol production process has been studied as
a strategy to increase its production and yield. Among these, Tween 80 stands out because it
has a lower cost than other additives. Thus, the aim of this study was to evaluate the ethanol
production from green coconut fiber using a combined steam explosion and alkaline
pretreatment, comparing the simultaneous saccharification and fermentation (SSF) and semisimultaneous saccharification and fermentation (SSSF) strategies. The use of Tween 80 in the
pretreatment, enzymatic hydrolysis, and fermentation steps was also investigated. Initially, the
influence of the temperature and humidity parameters in the steam explosion pretreatment were
evaluated on the production of glucose by enzymatic hydrolysis. The use of surfactant did not
influence delignification in the steam explosion pretreatment, however it increased the
conversion to glucose when compared to experiments without Tween 80. The use of surfactant
in enzymatic hydrolysis increased glucose production, reaching a maximum value of 20.31 ±
0.48 g/L with combined pretreated biomass and 1.0% (w/v) Tween 80. In the absence of
surfactant in any steps, the SSSF strategy stood out over the SSF. SSSF strategy showed the
highest yield and ethanol production and the strain that favored the best production was
Saccharomyces cerevisiae PE2. Different effects of Tween 80 were observed during
fermentation. The use of 2.0% (w/v) Tween 80 reduced cell viability as well as reduced ethanol
production in simulated medium, in SSF and SSSF. On the other hand, the use of 1.0% (w/v) Tween 80 increased the average ethanol production, although not enough to be statistically
significant. To increase ethanol production under 30% (w/v) solids loading, SSSF variations
were performed, including batch addition of biomass, batch addition of enzymes and
temperature variation every 6 h. SSSF with non-isothermal batch feeding and gradual addition
of enzymes stood out, reaching a maximum ethanol produced of 48.21 ± 1.13 g/L in the
presence of 1.0% (w/v) Tween 80. Therefore, the results indicate that the use of the combined
pretreatment generated a biomass with high cellulosic content that has a great potential for
ethanol production when fermentation strategies with Tween 80 were evaluated. |
|---|