초록
<P><B>Abstract</B></P><P>Fumaric acid is a naturally occurring organic acid that is an intermediate of the tricarboxylic acid cycle. Fungal species belonging to <I>Rhizopus</I> have traditionally been employed for the production of fumaric acid. In this study, <I>Escherichia coli</I> was metabolically engineered for the production of fumaric acid under aerobic condition. For the aerobic production of fumaric acid, the <I>iclR</I> gene was deleted to redirect the carbon flux through the glyoxylate shunt. In addition, the <I>fumA</I>, <I>fumB</I>, and <I>fumC</I> genes were also deleted to enhance fumaric acid formation. The resulting strain was able to produce 1.45 g/L of fumaric acid from 15 g/L of glucose in flask culture. Based on in silico flux response analysis, this base strain was further engineered by plasmid‐based overexpression of the native <I>ppc</I> gene, encoding phosphoenolpyruvate carboxylase (PPC), from the strong <I>tac</I> promoter, which resulted in the production of 4.09 g/L of fumaric acid. Additionally, the <I>arcA</I> and <I>ptsG</I> genes were deleted to reinforce the oxidative TCA cycle flux, and the <I>aspA</I> gene was deleted to block the conversion of fumaric acid into <SMALL>L</SMALL>‐aspartic acid. Since it is desirable to avoid the use of inducer, the <I>lacI</I> gene was also deleted. To increase glucose uptake rate and fumaric acid productivity, the native promoter of the <I>galP</I> gene was replaced with the strong <I>trc</I> promoter. Fed‐batch culture of the final strain CWF812 allowed production of 28.2 g/L fumaric acid in 63 h with the overall yield and productivity of 0.389 g fumaric acid/g glucose and 0.448 g/L/h, respectively. This study demonstrates the possibility for the efficient production of fumaric acid by metabolically engineered <I>E. coli</I>. Biotechnol. Bioeng. 2013; 110: 2025–2034. © 2013 Wiley Periodicals, Inc.</P>