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|Title: ||Novos transportadores de polióis em Debaryomyces hansenii|
|Other Titles: ||New polyol transporters from Debaryomyces hansenii|
|Authors: ||Pereira, Iliana Bento|
|Advisor: ||Prista, Catarina Geoffroy|
Dias, Maria da Conceição Loureiro
|Keywords: ||lignocellulosic waste|
|Issue Date: ||2011|
|Citation: ||Pereira, Iliana Bento - Novos transportadores de polióis em Debaryomyces hansenii. Lisboa: ISA, 2011|
|Abstract: ||Bioethanol production from lignocellulosic residues is a promising alternative for fossil fuels. However, it is still economically unviable due to the incapability of the main fermentative yeast, Saccharomyces cerevisiae, to ferment pentoses from hemicelluloses.
In this work, a molecular approach was followed, as a contribution to construct genetically modified strains of S. cerevisiae expressing putative polyol transporters, in order to upgrade the hemicelluloses fermentation by producing simultaneously plus-valuable dietetical polyols for food industry, such as xylitol.
A bibliographic screening for yeast species able to assimilate polyols revealed a restricted number of ascomycetes among the genus Candida, Debaryomyces and Pichia with potential interest as sinks of useful genes to improve polyol release.
To identify polyol transporters, a BlastP search on D. hansenii CBS 767 genome was performed, followed by cloning and characterization in S. cerevisiae. The presence of polyol(sugar)/H+ symport activity was evaluated for 18 substrates based on the external alkalinization of unbuffered cell suspensions upon polyol(sugar) addition.
In the present work 4 ORFs were cloned and 10 were characterized. Polyol/H+ symport activity (glycerol/H+, galactitol/H+, sorbitol/mannitol/ribitol/arabitol/H+) was detected in some of the strains tested.|
|Description: ||Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia|
|Appears in Collections:||BISA - Dissertações de Mestrado / Master Thesis|
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