초록
<P><B>ABSTRACT</B><P>Escherichia coli was metabolically engineered by expanding the shikimate pathway to generate strains capable of producing six kinds of aromatic compounds, phenyllactic acid, 4-hydroxyphenyllactic acid, phenylacetic acid, 4-hydroxyphenylacetic acid, 2-phenylethanol, and 2-(4-hydroxyphenyl)ethanol, which are used in several fields of industries including pharmaceutical, agrochemical, antibiotic, flavor industries, etc. To generate strains that produce phenyllactic acid and 4-hydroxyphenyllactic acid, the lactate dehydrogenase gene ( <I>ldhA</I> ) from <I>Cupriavidus necator</I> was introduced into the chromosomes of phenylalanine and tyrosine overproducers, respectively. Both the phenylpyruvate decarboxylase gene ( <I>ipdC</I> ) from <I>Azospirillum brasilense</I> and the phenylacetaldehyde dehydrogenase gene ( <I>feaB</I> ) from E. coli were introduced into the chromosomes of phenylalanine and tyrosine overproducers to generate phenylacetic acid and 4-hydroxyphenylacetic acid producers, respectively, whereas <I>ipdC</I> and the alcohol dehydrogenase gene ( <I>adhC</I> ) from <I>Lactobacillus brevis</I> were introduced to generate 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol producers, respectively. Expression of the respective introduced genes was controlled by the T7 promoter. While generating the 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol producers, we found that produced phenylacetaldehyde and 4-hydroxyphenylacetaldehyde were automatically reduced to 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol by endogenous aldehyde reductases in E. coli encoded by the <I>yqhD</I> , <I>yjgB</I> , and <I>yahK</I> genes. Cointroduction and cooverexpression of each gene with <I>ipdC</I> in the phenylalanine and tyrosine overproducers enhanced the production of 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol from glucose. Introduction of the <I>yahK</I> gene yielded the most efficient production of both aromatic alcohols. During the production of 2-phenylethanol, 2-(4-hydroxyphenyl)ethanol, phenylacetic acid, and 4-hydroxyphenylacetic acid, accumulation of some by-products were observed. Deletion of <I>feaB</I> , <I>pheA</I> , and/or <I>tyrA</I> genes from the chromosomes of the constructed strains resulted in increased desired aromatic compounds with decreased by-products. Finally, each of the six constructed strains was able to successfully produce a different aromatic compound as a major product. We show here that six aromatic compounds are able to be produced from renewable resources without supplementing with expensive precursors. </P></P>