초록
<P><B>Abstract</B></P> <P>In this study, an <SMALL>L</SMALL>-valine-producing strain was developed from <I>Corynebacterium glutamicum</I> ATCC13869 through deletion of the three genes <I>aceE</I>, <I>alaT</I> and <I>ilvA</I> combined with the overexpression of six genes <I>ilvB</I>, <I>ilvN</I>, <I>ilvC</I>, <I>lrp</I> <SUB> <I>1</I> </SUB>, <I>brnF</I> and <I>brnE</I>. Overexpression of <I>lrp</I> <SUB> <I>1</I> </SUB> alone increased <SMALL>L</SMALL>-valine production by 16-fold. Deletion of the <I>aceE</I>, <I>alaT</I> and <I>ilvA</I> increased <SMALL>L</SMALL>-valine production by 44-fold. Overexpression of the six genes <I>ilvB</I>, <I>ilvN</I>, <I>ilvC</I>, <I>lrp</I> <SUB> <I>1</I> </SUB>, <I>brnE</I> and <I>brnF</I> in the triple deletion mutant WCC003 further increased <SMALL>L</SMALL>-valine production. The strain WCC003/pJYW-4-<I>ilvBNC</I> <SUB> <I>1</I> </SUB>-<I>lrp</I> <SUB> <I>1</I> </SUB>-<I>brnFE</I> produced 243mM <SMALL>L</SMALL>-valine in flask cultivation and 437mM (51g/L) <SMALL>L</SMALL>-valine in fed-batch fermentation and lacked detectable amino-acid byproduct such as <SMALL>L</SMALL>-alanine and <SMALL>L</SMALL>-isoleucine that are usually found in the fermentation of <SMALL>L</SMALL>-valine-producing <I>C. glutamicum</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Overexpression of <I>lrp</I> <SUB> <I>1</I> </SUB> in <I>Corynebacterium glutamicum</I> ATCC13869 increased <SMALL>L</SMALL>-valine production by 16-fold. </LI> <LI> Deletion of 3 key genes in <I>C. glutamicum</I> ATCC13869 increased <SMALL>L</SMALL>-valine production by 44-fold. </LI> <LI> Expression of 6 genes in the 3-gene deletion mutant further increased <SMALL>L</SMALL>-valine production. </LI> <LI> The final strain could produce 0.47mol of <SMALL>L</SMALL>-valine from 1mol of glucose. </LI> </UL> </P>