초록
<P><I>p</I>-Coumaric acid is the precursor of phenylpropanoids, which are plant secondary metabolites that are beneficial to human health. Tyrosine ammonia lyase catalyzes the production of <I>p</I>-coumaric acid from tyrosine. Because of their photosynthetic ability and biosynthetic versatility, cyanobacteria are promising candidates for the production of certain plant metabolites, including phenylpropanoids. Here, we produced <I>p</I>-coumaric acid in a strain of transgenic cyanobacterium <I>Synechocystis</I> sp. Pasteur Culture Collection 6803 (hereafter <I>Synechocystis</I> 6803). Whereas a strain of <I>Synechocystis</I> 6803 genetically engineered to express <I>sam8</I>, a tyrosine ammonia lyase gene from the actinomycete <I>Saccharothrix espanaensis</I>, accumulated little or no <I>p-</I>coumaric acid, a strain that both expressed <I>sam8</I> and lacked <I>slr1573</I>, a native hypothetical gene shown here to encode a laccase that oxidizes polyphenols, produced ∼82.6 mg/L <I>p-</I>coumaric acid, which was readily purified from the growth medium.</P>