초록
<P><B>Abstract</B><P>The L‐serine exporters ThrE and SerE play important roles in L‐serine production by <I>Corynebacterium glutamicum</I>. Deletion of both <I>thrE</I> and <I>serE</I> decreased L‐serine titer by 60%, suggesting the existence of other L‐serine exporters. A comparative transcriptomics identified NCgl0254 and NCgl0255 as novel L‐serine exporters. Further analysis of the contributions of ThrE, SerE, NCgl0254, and NCgl0255 found that SerE was the major L‐serine exporter in <I>C. glutamicum</I> and these four L‐serine exporters were responsible for 79.7% of L‐serine export. Deletion of one L‐serine exporter upregulated the transcription levels of the other three, which might be coursed by increased intracellular concentrations of L‐serine. Overexpression of NCgl0254 and NCgl0255 increased L‐serine titer by 20.8% in <I>C</I>. <I>glutamicum</I> A36, while overexpression of the four L‐serine exporters increased L‐serine production by 31.9% (41.1 g·L<SUP>−1</SUP>) in <I>C</I>. <I>glutamicum</I> A36. The identification of novel L‐serine exporters in <I>C. glutamicum</I> will help to improve industrial production of L‐serine.</P></P>