Evolutionary engineering towards the optimization of fruit juice fermentations
Autor(a) principal: | |
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Data de Publicação: | 2019 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10362/89712 |
Resumo: | The industry has been exploiting the development of new fermented fruit-based products, since they have potential in the increase of nutritional value and health promotion. However, the fermentation of fruity substrates is often disturbed by the presence of aromatic substances, which while giving to the juice a more intense and natural aroma, can be highly inhibitory for microbial growth. In this context, in the current study, the fermentative performance of the yeasts Schizosaccharomyces pombe and Torulaspora delbrueckii was evaluated in orange juices containing different concentrations of orange essential oils. The impact of orange essential oils on yeast growth profiles in various culture media was also estimated. After observing inhibitory effects on the lag phases of yeast growth, different adaptive evolution approaches were adopted for the two yeasts. The purpose of these experiments was to obtain spontaneous mutants through natural selection, which would provide a phenotype of higher resistance to orange essential oils, assuming that a higher tolerance would lead to decreased growth lag times and therefore would accelerate the fermentation process of “fresh” orange juice (not from concentrate-nfc), which has higher concentrations of orange essential oils. The T. delbrueckii cell-based experimental evolution yielded a stable strain (E16900dT), which showed higher tolerance to orange essential oils. This strain fermented orange juice, which had higher concentrations of orange oils, faster than wild-type cells when inoculated on the same substrate. On the other hand, experimental evolutions starting with Sch. pombe resulted in strains with unstable phenotypes and, therefore, it was not possible to obtain a stable strain more tolerant to orange essential oils. Furthermore, in T. delbrueckii, differences in gene expression of three genes related to cell wall stability (PIR3), occurrence of oxidative stress (GPX2), and plasma membrane integrity (ERG6) were studied in the presence and absence of orange essential oils in chemically defined culture medium. RT-qPCR results revealed an overexpression of a glutathione enzyme peroxidase (Gpx2p), responsible for the cellular response in the presence of oxidative stress, leading to the conclusion that loss of viability of T. delbrueckii in the presence of orange essential oils may be due to oxidative stress. |
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Evolutionary engineering towards the optimization of fruit juice fermentationsorange essential oilsfermentationlag phaseadaptive evolutionDomínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e TecnologiasThe industry has been exploiting the development of new fermented fruit-based products, since they have potential in the increase of nutritional value and health promotion. However, the fermentation of fruity substrates is often disturbed by the presence of aromatic substances, which while giving to the juice a more intense and natural aroma, can be highly inhibitory for microbial growth. In this context, in the current study, the fermentative performance of the yeasts Schizosaccharomyces pombe and Torulaspora delbrueckii was evaluated in orange juices containing different concentrations of orange essential oils. The impact of orange essential oils on yeast growth profiles in various culture media was also estimated. After observing inhibitory effects on the lag phases of yeast growth, different adaptive evolution approaches were adopted for the two yeasts. The purpose of these experiments was to obtain spontaneous mutants through natural selection, which would provide a phenotype of higher resistance to orange essential oils, assuming that a higher tolerance would lead to decreased growth lag times and therefore would accelerate the fermentation process of “fresh” orange juice (not from concentrate-nfc), which has higher concentrations of orange essential oils. The T. delbrueckii cell-based experimental evolution yielded a stable strain (E16900dT), which showed higher tolerance to orange essential oils. This strain fermented orange juice, which had higher concentrations of orange oils, faster than wild-type cells when inoculated on the same substrate. On the other hand, experimental evolutions starting with Sch. pombe resulted in strains with unstable phenotypes and, therefore, it was not possible to obtain a stable strain more tolerant to orange essential oils. Furthermore, in T. delbrueckii, differences in gene expression of three genes related to cell wall stability (PIR3), occurrence of oxidative stress (GPX2), and plasma membrane integrity (ERG6) were studied in the presence and absence of orange essential oils in chemically defined culture medium. RT-qPCR results revealed an overexpression of a glutathione enzyme peroxidase (Gpx2p), responsible for the cellular response in the presence of oxidative stress, leading to the conclusion that loss of viability of T. delbrueckii in the presence of orange essential oils may be due to oxidative stress.Gonçalves, PaulaOom, Maria MadalenaRUNGil, Cátia Vieira2022-10-01T00:30:47Z2019-11-2220192019-11-22T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10362/89712enginfo: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:RCAAP2024-03-11T04:39:58Zoai:run.unl.pt:10362/89712Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:37:03.692299Repositório 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 |
Evolutionary engineering towards the optimization of fruit juice fermentations |
title |
Evolutionary engineering towards the optimization of fruit juice fermentations |
spellingShingle |
Evolutionary engineering towards the optimization of fruit juice fermentations Gil, Cátia Vieira orange essential oils fermentation lag phase adaptive evolution Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias |
title_short |
Evolutionary engineering towards the optimization of fruit juice fermentations |
title_full |
Evolutionary engineering towards the optimization of fruit juice fermentations |
title_fullStr |
Evolutionary engineering towards the optimization of fruit juice fermentations |
title_full_unstemmed |
Evolutionary engineering towards the optimization of fruit juice fermentations |
title_sort |
Evolutionary engineering towards the optimization of fruit juice fermentations |
author |
Gil, Cátia Vieira |
author_facet |
Gil, Cátia Vieira |
author_role |
author |
dc.contributor.none.fl_str_mv |
Gonçalves, Paula Oom, Maria Madalena RUN |
dc.contributor.author.fl_str_mv |
Gil, Cátia Vieira |
dc.subject.por.fl_str_mv |
orange essential oils fermentation lag phase adaptive evolution Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias |
topic |
orange essential oils fermentation lag phase adaptive evolution Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias |
description |
The industry has been exploiting the development of new fermented fruit-based products, since they have potential in the increase of nutritional value and health promotion. However, the fermentation of fruity substrates is often disturbed by the presence of aromatic substances, which while giving to the juice a more intense and natural aroma, can be highly inhibitory for microbial growth. In this context, in the current study, the fermentative performance of the yeasts Schizosaccharomyces pombe and Torulaspora delbrueckii was evaluated in orange juices containing different concentrations of orange essential oils. The impact of orange essential oils on yeast growth profiles in various culture media was also estimated. After observing inhibitory effects on the lag phases of yeast growth, different adaptive evolution approaches were adopted for the two yeasts. The purpose of these experiments was to obtain spontaneous mutants through natural selection, which would provide a phenotype of higher resistance to orange essential oils, assuming that a higher tolerance would lead to decreased growth lag times and therefore would accelerate the fermentation process of “fresh” orange juice (not from concentrate-nfc), which has higher concentrations of orange essential oils. The T. delbrueckii cell-based experimental evolution yielded a stable strain (E16900dT), which showed higher tolerance to orange essential oils. This strain fermented orange juice, which had higher concentrations of orange oils, faster than wild-type cells when inoculated on the same substrate. On the other hand, experimental evolutions starting with Sch. pombe resulted in strains with unstable phenotypes and, therefore, it was not possible to obtain a stable strain more tolerant to orange essential oils. Furthermore, in T. delbrueckii, differences in gene expression of three genes related to cell wall stability (PIR3), occurrence of oxidative stress (GPX2), and plasma membrane integrity (ERG6) were studied in the presence and absence of orange essential oils in chemically defined culture medium. RT-qPCR results revealed an overexpression of a glutathione enzyme peroxidase (Gpx2p), responsible for the cellular response in the presence of oxidative stress, leading to the conclusion that loss of viability of T. delbrueckii in the presence of orange essential oils may be due to oxidative stress. |
publishDate |
2019 |
dc.date.none.fl_str_mv |
2019-11-22 2019 2019-11-22T00:00:00Z 2022-10-01T00:30:47Z |
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/10362/89712 |
url |
http://hdl.handle.net/10362/89712 |
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.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 |
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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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1799137987641999360 |