초록
<P>A modified 6-phosphofructo-1-kinase was expressed in a citrate producing <I>Aspergillus niger</I> strain in combination with <I>cis</I>-aconitate decarboxylase from <I>Aspergillus terreus</I> to study the effect on the production of itaconic acid. The modified <I>pfkA</I> gene was also expressed in combination with the itaconic acid biosynthetic cluster from <I>A. terreus</I>, which consists of <I>cis-</I>aconitate decarboxylase <I>cadA</I>, a putative mitochondrial transporter <I>mttA</I> and a putative plasmamembrane transporter <I>mfsA</I>. The combined expression of <I>pfkA</I> and <I>cadA</I> resulted in increased citrate levels, but did not show increased itaconic acid levels. The combined expression of <I>pfkA</I> with the itaconic acid biosynthetic cluster resulted in significantly increased itaconic acid production at earlier time points. Also the itaconic acid productivity increased significantly. The maximum itaconic acid productivity that was reached under these conditions was 0.15 g/L/h, which is only a factor 17 lower than the 2.5 g/L/h that according to the US Department of Energy should be achieved to have an economically feasible production process.</P>