• Korean Journal of Microbiology
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• v.36 no.3
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• pp.236-241
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• 2000

A defensin is an inducible antibacterial peptide from a fleshfly and contains 40 residues basic peptide with six cysteines. For the consiruction of recombinant S cerevisiae expressing defensin, the structural gene coding for active defensin was chemically synthesized and fused in fiam to GAP promoter, MFul preprosequence and the GAL7 transcription terminator, generating a recombinant plasnlid pGMD18. S. ce~evisine 2805 Gells were transror~ned to uracil prototroph by the pGMDl8 arid the transformed cells showing antibacterial activity against 111. luteus TAM1056 were selected by growth inhibition zone assay. The optimal culture conditions for the unprovement of the defensin production of a selected tmdonnant were investigated. The optirmzed medium containing 0.4% yeast extract, 2% corn steep liquor, 2.5% glucose and 0.05% $C_2CO_3$, could be determined and the optimum lemperature. and initial pH could be detennnied as $28^{\circ}C$ and pH 3, ~mpectively. The optimized conditioiis revealed the trvofold Increase in the cell growth and the fourfold in the antibaclerial activity. coinpar-ed with tllc Yl'D medium.