Banca de QUALIFICAÇÃO: BEATRIZ MENEGHETTI COSTA DE ARAÚJO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : BEATRIZ MENEGHETTI COSTA DE ARAÚJO
DATE: 30/06/2023
TIME: 09:00
LOCAL: Via Google Meet
TITLE:

VALUE OF GREEN COCONUT FIBER FOR THE PRODUCTION OF SECOND-GENERATION LIGNOSULFONATE AND ETHANOL

KEY WORDS:

lignocellulosic biomass, lignosulfonate, green coconut, lignin, enzymatic hydrolysis, ethanol.

PAGES: 91
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Bioquímicos
SUMMARY:

The green coconout cultivation is present in several states of Brazil. Despite the variety of products derived from coconut, approximately 80-85% becomes waste, when improperly disposed, causes environmental problems, but which has great potential for use as lignocellulosic biomass, composed, mainly, of cellulose, hemicellulose and lignin. By being pre-treated to remove lignin (delignify) from the cellulosic matrix, the biomass has your recalcitrance reduced, allowing the access of cellulolytic enzymes to the polysaccharides of interest, which will be converted into fermentable sugars, then into second-generation ethanol. It is highlighted that the removal of lignin in the pre-treatment is not total, and may cause a non-productive adsorption in the enzymes used in hydrolysis, reducing their access to the polysaccharides, and decreasing the cellulosic conversion into sugars. Surfactants addition is an alternative that promote conformational stability and stabilize the electrostatic forces of repulsion between the enzyme and the lignin. In this context, the present study evaluated ethanol production and surfactant lignosulfonate (LS) production. The sugar production in enzymatic hydrolysis was studied by varying the biomass concentration and the enzymatic load, after pre-treatments with 2.0% sodium hydroxide (m/v) (test D) and combined (steam explosion at 210ºC, 10 minutes and 20 bar, followed by treatment with 2.0% sodium hydroxide) (test E). Then, the ethanolic production was evaluated for both tests, varying the solids load and in simultaneous (SSF) and semi-simultaneous (SSSF) saccharification and fermentation strategies. The lignosulfonate produced from a lignin sulfomethylation was added in the biomass enzymatic hydrolysis resulting from the combined pretreatment, in order to evaluate its effect on the sugars yield. In the enzymatic hydrolysis, the increase in the solid load showed a significant increase in the glucose concentration obtained for both tests. However, the variation in the enzymatic load was not statistically significant. Only for test E, at 15% solids, with 15 FPU/g (>34 g/L) and 20 FPU/g (>31 g/L). In fermentation, the change in fermentation strategy did not indicate a significant variation in ethanol production for test D, neither the variation in enzymatic load, which may indicate an excess of non-productive adsorption in the enzyme, due to its high retention rate after treatment (around 44%). In turn, for test E, the significant increase in enzymatic load increased the ethanol produced concentration. In addition, changing the strategy from SSF (at 20 FPU/g) to SSSF (at 15 FPU/g) showed an increase equivalent to 40% in the ethanol obtained concentration, while reducing about 25% of used enzyme. Regarding lignosulfonates, FTIR analyzes corroborate the efficiency of sulfomethylation process for sulfonation of the aromatic groups of lignin. As for its addition in enzymatic hydrolysis, for a concentration of 0.5 g/L (1% m/m of biomass), it showed a 30% increase in cellulosic conversion. Therefore, the results indicate that increasing the amount of solids in enzymatic hydrolysis increases cellulosic conversion, but increasing the enzymatic load is not always necessary. In addition, it was verified that the change in the fermentation strategy, in some cases, allows the reduction of the amount of cormaceous enzyme used, even increasing the production of ethanol in the process. Furthermore, lignosulfonate is efficient in reducing the non-productive adsorption of lignin on the enzyme during the enzymatic hydrolysis process.

COMMITTEE MEMBERS:
Presidente - 1346198 - EVERALDO SILVINO DOS SANTOS
Interno - 3304882 - CARLOS EDUARDO DE ARAÚJO PADILHA
Externo ao Programa - 027.194.253-38 - SÉRGIO DANTAS DE OLIVEIRA JÚNIOR
Externo à Instituição - PEDRO FERREIRA DE SOUZA FILHO - UFPE