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KMID : 0364820190550020143
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Korean Journal of Microbiology
2019 Volume.55 No. 2 p.143 ~ p.148
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A newly isolated Klebsiella pneumoniae producing a thermostable stereo-selective esterase for production of D?β-acetylthioisobutyric acid
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Chung Yong-Joon
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Abstract
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The synthesis of captopril as an important chiral drug in commerceneeds expensive resolution process of racemic mixture. Microorganisms,producing a thermostable esterase that catalyzes thestereo-selective hydrolysis of methyl DL-β-acetylthioisobutyrate(DL-ester) to D-β-acetylthioisobutyric acid (DAT) were screenedfrom soils. Among the strains tested, strain No CJ-317 and strainNo CJ-187 with highest activity were selected as the best DATproducer. The newly isolated microorganisms were identifiedrespectively, as Klebsiella pneumoniae and Pseudomonas putida.
The cell activity of esterase from K. pneumoniae CJ-317 and P.
putida CJ-187 were showed an optimal reaction activity at 75°Cand 60°C, respectively. Also the cell activity of K. pneumoniaeCJ-317 was stable up to 80°C for 1 h, while that of P. putidaCJ-187 was not over 60°C. By varying the concentration ofDAT in the reaction mixture, the cell activity of P. putidaCJ-187 showed about 55% and 80% of product inhibition in thepresence of 2.5% (w/v) and 5.0% of DAT respectively. K.
pneumoniae CJ-317 had less product inhibition than P. putidaCJ-187 by about 35% and 44% at the same concentrationsrespectively. The esterase of newly isolated K. pneumoniaeCJ-317 could be useful for the stereo-selective hydrolysis ofDL-ester to DAT.
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KEYWORD
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Klebsiella pneumoniae, D-β-acetylthioisobutyric acid (DAT), esterase, stereo-selective, thermostable
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