Improving L-arabinose utilization of pentose fermenting Saccharomyces cerevisiaecells by heterologous expression of L-arabinose transporting sugar transportersReportar como inadecuado




Improving L-arabinose utilization of pentose fermenting Saccharomyces cerevisiaecells by heterologous expression of L-arabinose transporting sugar transporters - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Biotechnology for Biofuels

, 4:38

First Online: 12 October 2011Received: 29 June 2011Accepted: 12 October 2011

Abstract

BackgroundHydrolysates of plant biomass used for the production of lignocellulosic biofuels typically contain sugar mixtures consisting mainly of D-glucose and D-xylose, and minor amounts of L-arabinose. The yeast Saccharomyces cerevisiae is the preferred microorganism for the fermentative production of ethanol but is not able to ferment pentose sugars. Although D-xylose and L-arabinose fermenting S. cerevisiae strains have been constructed recently, pentose uptake is still a limiting step in mixed sugar fermentations.

ResultsHere we described the cloning and characterization of two sugar transporters, AraT from the yeast Scheffersomyces stipitis and Stp2 from the plant Arabidopsis thaliana, which mediate the uptake of L-arabinose but not of D-glucose into S. cerevisiae cells. A yeast strain lacking all of its endogenous hexose transporter genes and expressing a bacterial L-arabinose utilization pathway could no longer take up and grow with L-arabinose as the only carbon source. Expression of the heterologous transporters supported uptake and utilization of L-arabinose especially at low L-arabinose concentrations but did not, or only very weakly, support D-glucose uptake and utilization. In contrast, the S. cerevisiae D-galactose transporter, Gal2, mediated uptake of both L-arabinose and D-glucose, especially at high concentrations.

ConclusionsUsing a newly developed screening system we have identified two heterologous sugar transporters from a yeast and a plant which can support uptake and utilization of L-arabinose in L-arabinose fermenting S. cerevisiae cells, especially at low L-arabinose concentrations.

AbbreviationsDMdry mass

HAhemagglutinin

HPLChigh perfomance liquid chromatography

kDAkiloDaltons

PCRpolymerase chain reaction

SCsynthetic complete

KMMichaelis constant

vmaxmaximal enzyme reaction velocity

Electronic supplementary materialThe online version of this article doi:10.1186-1754-6834-4-38 contains supplementary material, which is available to authorized users.

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Autor: Thorsten Subtil - Eckhard Boles

Fuente: https://link.springer.com/



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