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KMID : 0364819870250010046
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Korean Journal of Microbiology
1987 Volume.25 No. 1 p.46 ~ p.51
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Modification of host cells and Expression of Recombinant E. coli trp plasmids for the increased Production of Tryptophan in Klebsiella pneulnoniae
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Abstract
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1
In order to increase the production of tryptophan by maximizing expression of recombinant trp plasmid, Klebsiella pneumoniae KC 105(pheA tyrA trpE trpR tyrR) was genetically modified.
KC 107, inosine monophospate(IMP) auxotroph from KC 105 and KC 100, histidine(His) auxotroph from KC 107 were also derived respectively to increase phosphoribosylpyrophosphate(PRPP) production which is required for tryptophan biosynthesis. From KC 107 phosphoribosylpyrophosphate consumption which is required for tryptophan biosynthesis. From KC 107 and KC 101, KC 109 and KC 110, both arginine auxotrophs were derived respectively.
To investigate the expression of recombinant trp plasmid in the selected K. pneumoniae mutants, the auxotrophic mutants were transformed with recombinant trp plasmids pSC 101-trpE Fe´, pSC 101-trpL( d att) trpE FBR (pSC 101-trp-AF). Amount of tryptophan produced and activities of tryptophan synthase of trpR-mutant(KC 100) and tyrRmutnat(KC 105) containing recombinant-plasmid pSC 101-trp operon were increased by 30-40% as compared with KC 99(pheA tyrA trpE) containing recombinant plasmid pSC 101-t.p operon. Activities of tryptophan synthase and production of tryptophan of KC 101 (His) and KC 109(Arg) containing recombinant plasmid pSC 111-trp operon were increase by two-fold as compared with KC 107 containing pSC 101-trp operon.
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