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Biotechnol Lett ; 43(1): 287-296, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32936375

RESUMO

OBJECTIVES: Chiral 2-hydroxycarboxylic acids and 2-hydroxycarboxamides are valuable synthons for the chemical industry. RESULTS: The biocatalytic syntheses of (R)-mandelic acid and (R)-mandelic acid amide by recombinant Escherichia coli clones were studied. Strains were constructed which simultaneously expressed a (R)-specific oxynitrilase (hydroxynitrile lyase) from the plant Arabidopsis thaliana together with the arylacetonitrilase from the bacterium Pseudomonas fluorescens EBC191. In addition, recombinant strains were constructed which expressed a previously described acid tolerant variant of the oxynitrilase and an amide forming variant of the nitrilase. The whole cell catalysts which simultaneously expressed the (R)-specific oxynitrilase and the wild-type nitrilase transformed in slightly acidic buffer systems benzaldehyde plus cyanide preferentially to (R)-mandelic acid with ee-values > 95%. The combination of the (R)-specific oxynitrilase with the amide forming nitrilase variant gave whole cell catalysts which converted at pH-values ≤ pH 5 benzaldehyde plus cyanide with a high degree of enantioselectivity (ee > 90%) to (R)-mandelic acid amide. The acid and the amide forming catalysts also converted chlorinated benzaldehydes with cyanide to chlorinated mandelic acid or chlorinated mandelic acid amides. CONCLUSIONS: Efficient systems for the biocatalytic production of (R)-2-hydroxycarboxylic acids and (R)-2-hydroxycarboxamides were generated.


Assuntos
Aldeído Liases , Proteínas de Bactérias , Escherichia coli/genética , Ácidos Mandélicos , Proteínas Recombinantes , Aldeído Liases/genética , Aldeído Liases/metabolismo , Amidas/metabolismo , Aminoidrolases/genética , Aminoidrolases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biotransformação , Escherichia coli/metabolismo , Ácidos Mandélicos/química , Ácidos Mandélicos/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Estereoisomerismo
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