Genetic engineering of pichia stipitis for fermentation of xylose

摘要

S useful genetic system has been developd for he treasformation of Pichia stipitis. This includes two selectable markers (URA3 and LEU2), intgerating and autonomous replication vectors, a pop-out casett that enables multiple largeted disruptions, and a genomic #lambda# -library for rapid cloning. Using this system we have cloned two genes for alcohol dehydrogenase (PsADH1 and PsADH2), two genes for pyruvate decarboxylase (PsPDCl and PsPDC2), and cytochrome c (PsCYCl). Disruption of PsAHI, but not PsADH2, resulted in increased xylitol production. Disruption of PsCYCl resulted in lower growth and higher ethanol yields. We have used it to heterologously express the gene for S. cerevisiae dihydroorotate dehydrogenase. this conferred the capacity for anserobic growth.