Banca de QUALIFICAÇÃO: CLEITIANE DA COSTA NOGUEIRA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : CLEITIANE DA COSTA NOGUEIRA
DATE: 26/02/2021
TIME: 14:00
LOCAL: https://meet.google.com/mca-regw-iff
TITLE:

CELLULOSIC ETANOL PRODUCTION UNDER HIGH POLYMER CONCENTRATION

KEY WORDS:

Green coconut; corn; polyethylene glycol; ethylene oxide-propylene oxide; detoxification; ethanol.

PAGES: 383
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Orgânicos
SUMMARY:

The conversion of agro-industrial waste 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, we highlight 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 enzymatic activity and increased vitality, viability and tolerance of yeast in fermentation medium 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 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 cell viability and 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 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 CC. However, the effect of polymers was more pronounced with CCV for the subsequent stages of hydrolysis and fermentation, probably due to the high biomass lignin content. The results of SSF with liquor and PEG for pretreated acid and hydrothermal CCV were 8.8 g.L^-1 and 9.3 g.L^-1 of ethanol, respectively. However,these values were exceeded when using untreated coconut (9.7 g.L^-1). Batch SSF from untreated CCV 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. 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, 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 CCV in the cellulosic ethanol industry.

BANKING MEMBERS:
Externo à Instituição - CARLOS EDUARDO DE ARAÚJO PADILHA
Presidente - 1346198 - EVERALDO SILVINO DOS SANTOS
Externo à Instituição - FRANCINALDO LEITE DA SILVA - IFPB
Externo à Instituição - PEDRO FERREIRA DE SOUZA FILHO