초록
<P><B>Abstract</B></P><P>Mutant α‐amino‐ε‐caprolactam (ACL) racemase (L19V/L78T) from <I>Achromobacter obae</I> with improved substrate specificity toward phenylalaninamide was obtained by directed evolution. The mutant ACL racemase and thermostable mutant <SMALL>D</SMALL>‐amino acid amidase (DaaA) from <I>Ochrobactrum anthropi</I> SV3 co‐expressed in <I>Escherichia coli</I> (pACLmut/pDBFB40) were utilized for synthesis of (<I>R</I>)‐phenylalanine and non‐natural (<I>R</I>)‐phenylalanine derivatives (4‐OH, 4‐F, 3‐F, and 2‐F‐Phe) by dynamic kinetic resolution (DKR). Recombinant <I>E. coli</I> with DaaA and mutant ACL racemase genes catalyzed the synthesis of (<I>R</I>)‐phenylalanine with 84% yield and 99% <I>ee</I> from (<I>RS</I>)‐phenylalaninamide (400 mM) in 22 h. (<I>R</I>)‐Tyrosine and 4‐fluoro‐(<I>R</I>)‐phenylalanine were also efficiently synthesized from the corresponding amide compounds. We also co‐expresed two genes encoding mutant ACL racemase and <SMALL>L</SMALL>‐amino acid amidase from <I>Brevundimonas diminuta</I> in <I>E. coli</I> and performed the efficient production of various (<I>S</I>)‐phenylalanine derivatives. Moreover, 2‐aminophenylpropionitrile was converted to (<I>R</I>)‐phenylalanine by DKR using a combination of the non‐stereoselective nitrile hydratase from recombinamt <I>E. coli</I> and mutant ACL racemase and DaaA from <I>E. coli</I> encoding mutant ACL racemase and DaaA genes.</P>