Banca de DEFESA: CLEITIANE DA COSTA NOGUEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : CLEITIANE DA COSTA NOGUEIRA
DATE: 12/04/2021
TIME: 14:00
LOCAL: https://meet.google.com/tym-uwbj-snj
TITLE:

Cellulosic ethanol production under high concentrations of ethylene oxide-based polymers

KEY WORDS:

green coconut, corn, polyethylene glycol, ethylene oxide-propylene oxide, detoxification, ethanol.

PAGES: 300
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Orgânicos
SUMMARY:

The conversion of agro-industrial wastes such as green coconut husk (GCH) and corncob (CC) into ethanol is a promising alternative for Brazil to overcome industrial, economic and environmental issues. However, the cellulosic ethanol production requires an improvement in its main stages: pretreatment, enzymatic hydrolysis and fermentation. For this purpose, researches have shown many possibilities. Among them, it can be highlighted the use of polymers such as polyethylene glycol (PEG) and its derivatives as coadjuvants in these stages, since, in addition to beneficially assisting the pretreatment of biomass, it has favored the enzymatic activity and increased the vitality, viability and tolerance of the yeast in fermentation media with inhibitors. Therefore, this study evaluated how the type of polymer and its concentration can influence the performance of each stage. For this, the GCH and CC biomasses (untreated and pretreated in hydrothermal, acid and alkaline conditions) and SigmaCell cellulose, yeasts (Saccharomyces cerevisiae CAT-1 and Kluyveromyces marxianus), and polymers (Triton X-100, Tween 80, PEG 4000 and EOPO 5800) at different concentrations were used during the studied stages. In addtion, fermentative strategies have been proposed to integrate these steps by using polymers. In fermentations in inhibitory medium, the polymers PEG and ethylene oxide-propylene oxide (EOPO) acted as detoxification agents, maintaining the cell viability and the ethanol production similar to the control without inhibitor and polymer. This behavior was directly related to the concentration of the polymer up to the values of 175 and 100 g.L^-1 for PEG 4000 and EOPO 5800, respectively. In simulated enzymatic hydrolysis, PEG and EOPO increased cellulolytic activity and the release of fermentable sugars in an environment rich in lignin. PEG 400 was successfully used in the simultaneous saccharification and fermentation (SSF) of the slurry from the pressurized hydrothermal pretreatment, increasing the ethanol titer from 6.43 g.L^-1 (control without PEG) to 7.87 g.L^-1. During acid pretreatment, PEG increased the delignification of the CC. However, the effect of polymers was more pronounced with the GCH for the subsequent stages of hydrolysis and fermentation, probably because of the high biomass lignin content. The results of SSF with liquor and PEG for pretreated acid and hydrothermal GCH were 8.8±0.8 g.L^-1 and 9.3±1.2 g.L^-1 of ethanol, respectively. However, these values were exceeded when using untreated coconut (9.7±0.5 g.L^-1). Batch SSF from untreated GCH reached 89.8% mass yield of ethanol, using 175 g.L^-1 PEG 4000, 20 FPU.g^-1 and 1x10⁸ cells.mL^-1 of S. cerevisiae CAT-1. The addition of PEG made it possible to operate the batch fed SSF using up to 30% (w/w) of solid loading, 13.3 FPU.g^-1 of enzyme loading and 1x10⁸ cells.mL^-1 of S. cerevisiae CAT-1, producing 35.1 g.L^-1 ethanol in 48 h. Therefore, the results indicated that PEG in high concentrations is an alternative to facilitate the processing of GCH in the cellulosic ethanol industry.

BANKING MEMBERS:
Externo à Instituição - CARLOS EDUARDO DE ARAÚJO PADILHA
Externo à Instituição - EMMANUEL DAMILANO DUTRA
Presidente - 1346198 - EVERALDO SILVINO DOS SANTOS
Externo à Instituição - FRANCINALDO LEITE DA SILVA - IFPB
Externo à Instituição - PEDRO FERREIRA DE SOUZA FILHO
Externo à Instituição - TELMA TEIXEIRA FRANCO - UNICAMP