Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties

Detalhes bibliográficos
Autor(a) principal: Pinheiro, Cristiana Carvalho
Data de Publicação: 2013
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10362/10809
Resumo: Dissertação para obtenção do Grau de Mestre em Biotecnologia
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spelling Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional propertiesExopolysaccharideDissolved oxygenPhosphateFunctional propertiesDissertação para obtenção do Grau de Mestre em BiotecnologiaFucoPol is a fucose-containing biopolymer produced by the bacterium Gram-negative, Enterobacter A47 DSM 23139. It is an exopolysaccharide (EPS) composed of neutral sugars (fucose, galactose, glucose), an acidic sugar (glucuronic acid), and also non-saccharide substituents (acetate, pyruvate and succinate). In this work, two primary objectives were considered: the optimization of EPS production by varying two different parameters, and the functional properties’ assessment of different EPS produced by the bacterium. In the optimization study, the influence of different dissolved oxygen concentrations (controlled at 10, 30 and 60% of air saturation), and the impact of phosphate concentration reduction in the culture medium (5.25 and 3.81 g L-1) were assessed. The objective was to evaluate not only the effect of both parameters on cellular growth and exopolysaccharide-synthesis, but also to determine their influence in EPS chemical composition. The best results were obtained with DO at 10%, with the highest EPS production (6.11 g L-1), and although a reduction of phosphate concentration didn’t affect the EPS production, it reduced the exopolysaccharide’s fucose content to 24%mol. Secondly, the functional properties of nine distinct exopolysaccharides synthesized by Enterobacter A47 under different cultivation conditions were evaluated. Rheologically, most of the EPS polymer solutions showed shear-thinning behavior, wherein EPS-s, EPS-g and GNEX achieved the highest apparent viscosity (0.2 - 0.3 Pa.s) at lower shear rates (0.3 to 1 s-1). Also, most of the polymers presented emulsifying capacity at different temperatures. Concerning the film-forming capacity, EPS-s, EPS-g and EPS-x films demonstrated to have good mechanical properties and high water vapour permeability. And, all polymers described flocculating activity at 0.01% of EPS, which was significantly diminished at lower concentration, 0.001%.Faculdade de Ciências e TecnologiaFreitas, Maria FilomenaReis, Maria d'AscensãoRUNPinheiro, Cristiana Carvalho2013-12-04T12:04:50Z20132013-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10362/10809TID:201755220enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-03-11T03:44:45Zoai:run.unl.pt:10362/10809Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:19:44.690216Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties
title Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties
spellingShingle Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties
Pinheiro, Cristiana Carvalho
Exopolysaccharide
Dissolved oxygen
Phosphate
Functional properties
title_short Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties
title_full Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties
title_fullStr Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties
title_full_unstemmed Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties
title_sort Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties
author Pinheiro, Cristiana Carvalho
author_facet Pinheiro, Cristiana Carvalho
author_role author
dc.contributor.none.fl_str_mv Freitas, Maria Filomena
Reis, Maria d'Ascensão
RUN
dc.contributor.author.fl_str_mv Pinheiro, Cristiana Carvalho
dc.subject.por.fl_str_mv Exopolysaccharide
Dissolved oxygen
Phosphate
Functional properties
topic Exopolysaccharide
Dissolved oxygen
Phosphate
Functional properties
description Dissertação para obtenção do Grau de Mestre em Biotecnologia
publishDate 2013
dc.date.none.fl_str_mv 2013-12-04T12:04:50Z
2013
2013-01-01T00:00:00Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10362/10809
TID:201755220
url http://hdl.handle.net/10362/10809
identifier_str_mv TID:201755220
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron:RCAAP
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
repository.mail.fl_str_mv
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