초록
<P> <I>Enterobacter aerogenes</I>, a gram-negative, rod-shaped bacterium, is an effective producer of succinate from glucose via the reductive tricarboxylic acid cycle under anaerobic conditions. However, to date, succinate-exporter genes have not been identified in <I>E. aerogenes</I>, although succinate exporters have a large impact on fermentative succinate production. Recently, we genetically identified <I>yjjP and yjjB</I>, as genes encoding a succinate transporter in <I>Escherichia coli</I>. Evaluation of the <I>yjjPB</I> homologs in <I>E. aerogenes</I> (<I> <I>EayjjPB</I> genes</I>) showed that succinate accumulation increased from 4.1 g L<SUP>−1</SUP> to 9.1 g L<SUP>−1</SUP> when the <I>EayjjPB</I> genes were expressed under aerobic conditions. Under anaerobic conditions, succinate yield increased from 53% to 60% by <I>EayjjPB</I> expression and decreased to 48% by deletion of <I>EayjjPB</I>. Furthermore, the production levels of fumarate and malate, which are intermediates of the succinate-biosynthesis pathway, were also increased by <I>EayjjPB</I> expression. A complementation assay conducted in <I>Corynebacterium glutamicum</I> strain AJ110655Δ<I>sucE</I>1 demonstrated that both EaYjjP and EaYjjB are required for the restoration of succinate production. Taken together, these results suggest that EaYjjPB function as a dicarboxylate transporter in <I>E. aerogenes</I> and that the products of both genes are required for dicarboxylate transport.</P>