Heterologous expression of one xylose transporter from Aspergillus nidulans in S. cerevisiae strain

Abstract

Efficient conversion of sugars present in lignocellulosic materials is crucial for processes to produce second-generation ethanol. However, the microorganism most suitable conditions for industrial Saccharomyces cerevisiae has deficiency in metabolizing pentoses such as xylose which consists of a majority of sugars from lignocellulosic materials. Faced with this metabolic failure has become necessary to seek alternatives to obtain an efficient fermentation in the production of second-generation ethanol . Aiming to improve the uptake and assimilation of xylose in strains of S. cerevisiae, we attempted to select xylose transporters of Aspergillus nidulans by microarray and expressing them in yeast strains containing genes responsible for conducting the pentose phosphate pathway. Transporter gene ( AN0250 ) was subjected to the PCR process ErrorProne by a single recombinant Taq DNA polymerase, this enzyme does not have great fidelity to the extent of new DNA strand provides the insertion of random mutations in the gene. To promote higher mutation rates varying amounts of manganese ( 2.5 , 3.5, and 5.0 ul 5 mM MnCl2 ) were introduced in the PCR reactions. The DNA fragments obtained were then transformed into strains of S. cerevisiae ( EBYVW 4000:: pRH274 and SC9721 ) in a medium containing xylose as a carbon source, to allow the selection of candidates which had the highest metabolism of xylose. (AU)