Expression of Bacillus sp beta-xylosidase gene (xylB) in Saccharomyces cerevisiae

beta-Xylosidase gene (xylB) from Bacillus sp. was amplified and inserted be tween GAL10 promoter and GAL7 terminator. For the secretory production of x ylB in Saccharomyces cerevisiae, in-frame fusion of the exoinulinase signal sequence (INU1s) of Kluyveromyces marxianus to the upstream of xylB was co nducted. When a transformant of S. cerevisiae harboring the resulting plasm id was grown on galactose-containing medium, most of beta-xylosidase activi ty was localized in the periplasmic space of yeast and a maximum total acti vity reached about 2.9 unit ml(-1) at 42 h cultivation. The recombinant bet a-xylosidase was produced as an active dimer form.