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Electronic Journal of Biotechnology
Universidad Católica de Valparaíso
ISSN: 0717-3458
Vol. 17, No. 5, 2014, pp. 246-249
Bioline Code: ej14040
Full paper language: English
Document type: Short Communication
Document available free of charge

Electronic Journal of Biotechnology, Vol. 17, No. 5, 2014, pp. 246-249

 en On the fermentative behavior of auxotrophic strains of Saccharomyces cerevisiae check for this species in other resources
Paciello, Lucia; Zueco, Jesus & Landi, Carmine

Abstract

Background: The selection of new yeast strains could lead to improvements in bioethanol production. Here, we have studied the fermentative capacity of different auxotrophic mutants of Saccharomyces cerevisiae check for this species in other resources , which are routinely used as hosts for the production of heterologous proteins. It has recently been found that these strains exhibit physiological alterations and peculiar sensitivities with respect to the parental prototrophic strains from which they derive. In this work the performance of auxotrophic S. cerevisiae CEN.PK strains was compared to the corresponding prototrophic strain, to S. cerevisiae T5bV, a strain isolated from grape must and to another auxotrophic strain, S. cerevisiae BY4741.
Results: The results indicate that the fermentative capacity of strains grown in 2% glucose was similar in all the strains tested. However, in 15% initial glucose, the auxotrophic strains exhibited a more than doubled ethanol yield on biomass (10 g g-1dw) compared to the prototrophic strains (less than 5 g g-1dw). Other tests have also evidenced that in medium depletion conditions, ethanol production continues after growth arrest.
Conclusions: The results highlight the capacity of auxotrophic yeast strains to produce ethanol per mass unit, in a higher amount with respect to the prototrophic ones. This leads to potential applications for auxotrophic strains of S. cerevisiae in the production of ethanol in both homogeneous and heterogeneous phases (immobilized systems). The higher ethanol yield on biomass would be advantageous in immobilized cell systems, as a reduced yeast biomass could greatly reduce the mass transfer limitations through the immobilization matrix.

Keywords
Auxotrophic yeast; CEN.PK strains; Ethanol yields; Fermentative capacity; Fermentative metabolism

 
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