Abstract
The inability of Saccharomyces cerevisiae to utilize xylose is attributed to its inability to convert
xyloseto xylulose. Lowxylosereductaseandxylitoldehydrogenaseactivities in S. cerevisiaeareregardedas the
reason ofblocking the pathway from xylose to xylulose. In previous study, we cloned and expressed the xylose
reductase gene from Candida shehataein S. cerevisiaewhichenables itto growinxylose-containingmedium. In
this study, we investigatedthe activity ofxylitol dehydrogenase gene of C. shehataein S. cerevisiae. The xylitol
dehydrogenase gene (XYL2) from C. shehataewas amplifidbypolymerase chainreaction(PCR). Itwas placed
intoplasmidpSFAUtoproducetherecombinantexpressionvectorpSFAU-XDH.Subsequently,thepSFAU-XDH
vectorwastransformedinto S. cerevisiaeTISTR5339 toproducearecombinant S. cerevisiaeTISTR5339-XDH.
Therecombinant S. cerevisiaeshowedhighergrowthratethantheuntransformedstraininmediacontainingxylitol
as a carbon source. The specifi enzyme activity ofxylitol dehydrogenase in the recombinant S. cerevisiaewas
determined. The highestspecifi activitywas 0.805 mUmg-1 proteinor0.013 nkatmg-1. This workdemonstrates
the functionality ofthe gene xylitol dehydrogenase from C. shehataein S. cerevisiae.