Stereo- and regioselective hydroxylation of alpha-ionone by Streptomyces strains.
A total of 215 Streptomyces strains were screened for their capacity to regio- and stereoselectively hydroxylate beta- and/or alpha-ionone to the respective 3-hydroxy derivatives. With beta-ionone as the substrate, 15 strains showed little conversion to 4-hydroxy- and none showed conversion to the 3-hydroxy product as desired. Among these 15 Streptomyces strains, S. fradiae Tü 27, S. arenae Tü 495, S. griseus ATCC 13273, S. violaceoniger Tü 38, and S. antibioticus Tü 4 and Tü 46 converted alpha-ionone to 3-hydroxy-alpha-ionone with significantly higher hydroxylation activity compared to that of beta-ionone. Hydroxylation of racemic alpha-ionone [(6R)-(-)/(6S)-(+)] resulted in the exclusive formation of only the two enantiomers (3R,6R)- and (3S, 6S)-hydroxy-alpha-ionone. Thus, the enzymatic hydroxylation of alpha-ionone by the Streptomyces strains tested proceeds with both high regio- and stereoselectivity.
Institut für Technische Biochemie, Universität Stuttgart, Stuttgart, Germany.
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Lutz-Wahl
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Fischer
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Schmidt-Dannert
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Wohlleben
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Hauer
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Schmid
D006900:Hydroxylation; D045792:Norisoprenoids; D019906:Nuclear Magnetic Resonance, Biomolecular; D013045:Species Specificity; D013237:Stereoisomerism; D013302:Streptomyces / Q000378:metabolism*; D013303:Streptomyces antibioticus / Q000378:metabolism; D013305:Streptomyces griseus / Q000378:metabolism; D013729:Terpenes / Q000378:metabolism*
D045792:Norisoprenoids; D013729:Terpenes; C011879:alpha-ionone