• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.206-211
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• 2004

Levansucrase gene(lscA) from Pseudomonas aurantiaca was subcloned downstream of GAL1 promoter in pYES 2.0 and pYInu-AT [GAL10 promoter ＋ exoinulinase signal sequence of Kluyveromyces marxianus], resulting pYES-lscA and p YInu-lscA, respectively. The two expression plasmids were introduced into an invertase-deficient strain, Sacchromayces cerevisiae SEY2102, and transformants with high activity of levansucrase were selected. When each yeast transform ants was cultivated in medium containing galactose, the extracellular and intracellular activities of levansucrase reached about 8.62 U/ml with the strain harboring pYES-lscA and 5.43 U/ml with the strain harboring pYInu-lscA. The levansucrase activity of 80% was detected in the periplasmic space and cytoplasm. The levansucrase activity in the medium of SEY2102/pYInu-lscA was 0.87 U/ml whereas that of SEY2102/pYES-lscA was 0.47 U/ml, which implying the exoinulinase signal sequence didn't enhance the secretion efficiency of levansucrase. Furthermore, the recombinant levansucrase expressed in yeast seems to be produced as a hyper-glycosylated form.