Banca de DEFESA: FRANCINALDO LEITE DA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : FRANCINALDO LEITE DA SILVA
DATA : 19/12/2017
HORA: 14:00
LOCAL: Auditório do NUPEG
TÍTULO:

A DEFINIR.

PALAVRAS-CHAVES:

Carnauba; bioethanol; pre-treatments; cellulase enzymes; lignocellulose; SSF.

PÁGINAS: 133
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Química
RESUMO:

Native to Brazil, Carnauba (Copernicia prunifera) has been used for several purposes, including the wax production from its leaves, which process generates a considerable amount of residue. Such a residue is characterized as a fiber rich in cellulose and therefore with potential latent for use as a source of carbon for the production of cellulolytic enzymes and bioethanol. However, the chemical structure of this material presents cellulose bound to structurally complex components, such as hemicellulose and lignin, which hinders the production of cellulases from the fermentation by filamentous fungi, as well as its enzymatic hydrolysis, being essential to use of a pre-treatment for the viability of these processes. The present study evaluated the effect of different pre-treatments on carnauba straw for the production of lignocellulolytic enzymes and for the enzymatic hydrolysis with a view to the production of cellulosic ethanol through the concepts of biorefinery and micro-distillery. In the first stage, carnauba straw residue was submitted to hydrothermal (HT), alkaline (AL), alkaline acid (AA) and alkaline hydrogen peroxide (A-HP) pre-treatments. The pretreated and untreated residues were chemically characterized according to the National Renewable Energy Laboratory (NREL) protocol and, physically, by MEV (Scanning Electron Microscopy), XRD (X-Ray Diffraction) and FTIR (Spectroscopy of Infrared by Fourier Transform). A part of each residue was used to produce enzymes by means of FES (Solid State Fermentation), using the fungus Trichoderma reesei CCT-2768. The FPAse, CMCase, β-glycosidase and xylanase activities of the extracts were estimated and production subsequently optimized. The other part of the residues was subjected to enzymatic hydrolysis by commercial enzymes, whose hydrolyzate was fermented by Saccharification and Simultaneous Fermentation (SSF), using Saccharomyces cerevisiae UFLA CA11, Saccharomyces cerevisiae CAT-1 and Kluyveromyces marxianus ATCC-36907. The results of the pre-treatments AL, AA and A-HP stood out in terms of the removal of lignin, according to the chemical and physical analysis of the residues. The studies showed that pre-treatment of carnauba straw with A-HP has a higher capacity to induce the production of lignocellulolytic enzymes when compared to other residues, such as coconut, cashew and sugar cane, pretreated by the same method . The optimization of the production of lignocellulolytic enzymes allowed the production of an enzymatic extract with FPase activity of 2.4 U / g and xylanases of 172 U / g. The application of the enzymatic extract in the hydrolysis of pre-treated sugarcane bagasse showed efficiency of 86.96%. The use of AL pre-treated carnauba residue in enzymatic hydrolysis, when using commercial enzymes, showed a higher conversion of sugars (64.43%) and, when submitted to SSF, produced 7.53 g / L of ethanol, using Kluyveromyces marxianus ATCC-36907 cultured at 45 ° C. The results show, therefore, the biotechnological potential of the carnauba residue for the production of cellulolytic enzymes and the production of bioethanol by means of biorefinery and micro distillery.

MEMBROS DA BANCA:
Presidente - 1346198 - EVERALDO SILVINO DOS SANTOS
Externo ao Programa - 3652554 - FRANCISCO CANINDE DE SOUSA JUNIOR
Externo à Instituição - MARIA VALDEREZ PONTE ROCHA - UFC
Externo à Instituição - NATHALIA KELLY DE ARAUJO - UFRN
Externo à Instituição - TELMA TEIXEIRA FRANCO - UNICAMP