| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 2.94 MB | Adobe PDF |
Authors
Abstract(s)
O trabalho desenvolvido teve como objetivo caracterizar biocompostos de valor acrescentado sintetizados pela microalga Chlorococcum amblystomatis. Para o efeito, foi realizado o seu crescimento em condições heterotróficas (HTN) e autotróficas (AT), sem (1) e com (2) indução de stress (privação de NO3-) em reator de coluna de bolhas (C) e em frascos (F). A extração de biomoléculas intracelulares sintetizadas pela C. amblystomatis foi efetuada por extração assistida por micro-ondas e extração contínua em Soxhlet, enquanto as biomoléculas extracelulares foram obtidas por precipitações alcoólicas. Os extratos resultantes foram avaliados em relação ao seu teor em diversas biomoléculas, nomeadamente polissacáridos, proteína total, compostos fenólicos e flavonoides totais. De um modo geral, os resultados obtidos sugerem que os meios de cultura resultantes da indução de stress exibiram maior teor em exopolissacáridos. O ensaio realizado em condições autotróficas em frascos sem indução de stress (AT_F2) apresentou os teores máximos em biocompostos intracelulares (polissacáridos ácidos, β-(1,3)-D-glucanos, proteína total, compostos fenólicos e flavonoides totais). Todos os extratos analisados apresentaram atividade antioxidante. Um dos extratos que exibiu maior conteúdo em polissacáridos neutros (MAE_AT_F1) foi fracionado por cromatografia de troca iónica. A identificação de polissacáridos nesta amostra foi realizada por eletroforese em gel de poliacrilamida utilizando diferentes métodos de coloração, tendo sido identificada a presença de ácido hialurónico e de polissacáridos de diversos tamanhos moleculares. Uma fração cromatográfica (F8) proveniente de um extrato de C. amblystomatis apresentarou atividade in vitro contra as bactérias Echerichia coli ATCC25922 e Staphylococcus aureus ATCC25923. Os extratos/amostras selecionados foram caraterizados estruturalmente por espetroscopia de infravermelho por transformada de Fourier (FTIR), validando a presença diversos tipos de polissacáridos, de proteínas e de lípidos. A presença de diversas biomoléculas nos extratos estudados e a sua capacidade antioxidante revelam o potencial biotecnológico de C. amblystomatis para aplicações biomédicas ou alimentar.
The aim of this work was to characterize value-added compounds biosynthesized by the microalga Chlorococcum amblystomatis. For this purpose, it was grown under heterotrophic (HTN) and autotrophic (AT) conditions, without (1) and with (2) stress induction (NO3- deprivation) in bubble column reactor (C) and flasks (F). The extraction of intracellular biomolecules synthesized by C. amblystomatis was performed by microwave-assisted extraction and Soxhlet continuous extraction, while the extracellular biomolecules were obtained by alcoholic precipitation. The resulting extracts were evaluated for their content in various biomolecules, namely polysaccharides, total protein, phenolic and flavonoid compounds. In general, the results obtained suggest that the media resulting from stress induction exhibited higher content in exopolysaccharides. The experiment carried out under autotrophic conditions in flasks without stress induction (AT_F2) showed the highest content in intracellular biocompounds (acidic polysaccharides, β-(1,3)-D-glucans, total protein, phenolic and flavonoid compounds). All the extracts analyzed showed antioxidant activity. One of the extracts that showed higher content in neutral polysaccharides (MAE_AT_F1) was fractionated by ion exchange chromatography. The identification of polysaccharides present in this sample was carried by polyacrylamide gel electrophoresis using different staining techniques, and the identified the presence of hyaluronic acid and polysaccharides with several molecular sizes. A chromatographic fraction (F8) from an extract of C. amblystomatis showed in vitro assay against the bacteria Echerichia coli ATCC25922 and Staphylococcus aureus ATCC25923. The selected extracts/samples were structurally characterized by Fourier Transform Infrared Spectroscopy (FTIR), validating the presence of different types of polysaccharides, proteins and lipids. The presence of various biomolecules in the studied extracts and their antioxidant potential reveal the biotechnological potential of C. amblystomatis for biomedical or food applications.
The aim of this work was to characterize value-added compounds biosynthesized by the microalga Chlorococcum amblystomatis. For this purpose, it was grown under heterotrophic (HTN) and autotrophic (AT) conditions, without (1) and with (2) stress induction (NO3- deprivation) in bubble column reactor (C) and flasks (F). The extraction of intracellular biomolecules synthesized by C. amblystomatis was performed by microwave-assisted extraction and Soxhlet continuous extraction, while the extracellular biomolecules were obtained by alcoholic precipitation. The resulting extracts were evaluated for their content in various biomolecules, namely polysaccharides, total protein, phenolic and flavonoid compounds. In general, the results obtained suggest that the media resulting from stress induction exhibited higher content in exopolysaccharides. The experiment carried out under autotrophic conditions in flasks without stress induction (AT_F2) showed the highest content in intracellular biocompounds (acidic polysaccharides, β-(1,3)-D-glucans, total protein, phenolic and flavonoid compounds). All the extracts analyzed showed antioxidant activity. One of the extracts that showed higher content in neutral polysaccharides (MAE_AT_F1) was fractionated by ion exchange chromatography. The identification of polysaccharides present in this sample was carried by polyacrylamide gel electrophoresis using different staining techniques, and the identified the presence of hyaluronic acid and polysaccharides with several molecular sizes. A chromatographic fraction (F8) from an extract of C. amblystomatis showed in vitro assay against the bacteria Echerichia coli ATCC25922 and Staphylococcus aureus ATCC25923. The selected extracts/samples were structurally characterized by Fourier Transform Infrared Spectroscopy (FTIR), validating the presence of different types of polysaccharides, proteins and lipids. The presence of various biomolecules in the studied extracts and their antioxidant potential reveal the biotechnological potential of C. amblystomatis for biomedical or food applications.
Description
Trabalho final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica – Perfil Bioprocessos.
Keywords
Microalgas verdes Compostos bioativos Polissacárido Extração assistida por micro-ondas Atividade antioxidante Atividade antibacteriana Green microalgae Bioactive compounds Polysaccharides EPS Microwave assisted extraction Antioxidant activity Antibacterial activity FTIR
Citation
GABRIEL, Catarina Coelho - Avaliação e caracterização de bioprodutos de valor acrescentado isolados de uma microalga produzida industrialmente. Lisboa: Instituto Superior de Engenharia de Lisboa, 2023. Dissertação de Mestrado.