Banca de DEFESA: AMANDA CAROLINE DE OLIVEIRA DINIZ
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.STUDENT : AMANDA CAROLINE DE OLIVEIRA DINIZ
DATE: 28/02/2023
TIME: 09:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:
KEY WORDS:
Bacterial cellulose; Komagataeibacter hansenii; Cereus jamacaru; HestrimSchramm.
PAGES: 77
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:
Bacterial cellulose (BC) is a promising biopolymer for replacing materials of fossil origin due to its high purity, biocompatibility, biodegradability, high elasticity, mechanical resistance, high specific surface area and porosity. However, production costs and biological inactivity are still challenges for industrial-scale production. Therefore, the pulp of Cereus jamacaru, a fruit from the northeast region, underutilized and little commercially explored, was investigated, aiming to identify a low-cost and nutrient-rich system that provides the bacteria Komagataeibacter hansenii with yield and properties equal to or greater than the standard HS medium. (Hestrim-Schramm). For this purpose, a physical-chemical characterization of the mandacaru fruit pulp was initially performed, which showed the following averages of carbohydrates (0.70 µmol.mL-1), citric acid (0.51%) and pH (4. 31). In view of this, medium with fruit juice P60 (60% m/v), P80 (80% m/v), P100 (100% m/v) and the standard medium were prepared in situ under static conditions. HS over the same amount of volume. After 15 days of fermentation, the samples were dried, characterized and analyzed by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis and water vapor permeability. It was found that the best yield and productivity of dry membranes was obtained for samples P80 (11.10 ± 0.51 g/L and 0.74 ± 0.04 g. L-1.day-1) and HS (10.84 ± 0.82 g/L and 0.72 ± 0.05 g. L-1.day-1), which were statistically similar, favoring the substitution of HS medium for a medium with almost total cost reduction. All samples showed high water retention capacity (≈ 97%). The membranes, presented important functional groups belonging to the chemical structure of type I cellulose, the highest percentage of crystallinity conferred to P80 (78.05%) which favored a more thermally stable material, confirmed by its fibrillar morphology, and by the permeability with permeation coefficient of (1.28 ± 0.11 x 10-10 g s-1m-1Pa). Thus, based on the results, the BC produced with the juice of the Cereus jamacaru fruit without adding extra nutrients proved to be promising, low cost and with potential to be explored in several applications such as in the food industry, packaging, cosmetics, adsorbent material of contaminants, among others.
COMMITTEE MEMBERS:
Presidente - 2572606 - GLORIA MARIA VINHAS
Externo à Instituição - JOSÉ FRANCIELSON QUEIROZ PEREIRA - UFRPE
Interna - 1283002 - YEDA MEDEIROS BASTOS DE ALMEIDA