Banca de QUALIFICAÇÃO: CATHERINE TEIXEIRA DE CARVALHO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : CATHERINE TEIXEIRA DE CARVALHO
DATA : 11/10/2019
HORA: 09:30
LOCAL: Auditório NUPEG (prédio do NUPEG 1)
TÍTULO:

A DEFINIR

PALAVRAS-CHAVES:

Cheese whey; Kluyveromyces sp; β-galactosidase; Ethanol; Lactose hydrolysis.

PÁGINAS: 147
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Química
RESUMO:

The present study aimed to evaluate the use of "coalho" cheese whey as substrate for the production of biomolecules by yeasts of the genus Kluyveromyces sp. and to evaluate processing strategies that enable the application of β-galactosidase in the food industry. In the first stage of this study, the yeast behavior for the production of β-gal and ethanol by submerged fermentation in different C:N concentrations was assessed. The yeast Kluyveromyces lactis NRRL Y-8279 presented better efficiency for co-production of β-Gal and ethanol. The maximum production of β-Gal was 21.09 ± 0.69 U/mL and ethanol 7.10 ± 0.09 g/L in 16 hours of cultivation. In face of the obtained results, for the second stage, a 22 experimental design was proposed in order to develop a purification strategy to the enzyme. The parameters pH and ionic strength were evaluated in order to obtain a high purification factor without impairment in the yield. The higher levels of both parameters on study enhanced the purification factor of β-gal to 2.00, with greater influence of ionic strength on the FP response. The purified enzyme was submitted to electrophoresis that presented a band with molecular weight around 120 kDa, the enzyme of interest. In the third and final stage of the study, we analyzed the hydrolysis conditions of lactose in the “coalho” cheese whey with the immobilized form of β-Gal in 1% (w/v) sodium alginate. For the immobilization system, the immobilization efficiency reached 66% and high recovered activity was achieved. In addition, the immobilized form of the enzyme presented higher stability to pH and temperature changes. The immobilized enzyme had a slightly lower rate of lactose conversion (46%) when compared to the crude enzyme extract (53%). For the gastrointestinal simulations, around 40% of the enzymatic activity was preserved after 2 hours of exposure to simulated gastrointestinal environments. Overall, the results described here are promising for the industrial applications of β-galactosidase from K. lactis.

MEMBROS DA BANCA:
Presidente - 1346198 - EVERALDO SILVINO DOS SANTOS
Externa ao Programa - 2578619 - ANA HELONEIDA DE ARAUJO MORAIS
Externa à Instituição - ANA LÚCIA FIGUEIREDO PORTO - UFRPE