초록
<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P><I>Corynebacterium glutamicum</I> was engineered for improvement of L‐lysine production and minimization of by‐products synthesis by genetically engineering.</P><P><B>RESULTS</B></P><P>The most promising recombinant strain <I>C. glutamicum</I> Lys9 produced 62.1 mmol L<SUP>‐1</SUP> L‐lysine with substrate‐specific yield (<I>Y</I><SUB>P/S</SUB>) of 0.28 mol per mol of glucose in shake flasks fermentation, whereas parental strain showed more than four times lower L‐lysine production and more than 10 times lower biomass‐specific yield (<I>Y</I><SUB>P/X</SUB>) than that of <I>C. glutamicum</I> Lys9. L‐lysine production and cell growth were drastically decreased by isocitrate dehydrogenase (ICD) attenuation in <I>aceE</I> deletion strains, indicating that down‐regulation of ICD activity in <I>aceE</I> deletion strains adversely affects L‐lysine production. In fed‐batch fermentation, <I>C. glutamicum</I> Lys9 produced 526 mmol L<SUP>‐1</SUP> L‐lysine, i.e. 96.8 g L<SUP>‐1</SUP> L‐lysine‐HCl with high yield of 0.422 mol per mol of glucose and productivity of 2.69 g L<SUP>‐1</SUP> h<SUP>‐1</SUP>. <I>Corynebacterium glutamicum</I> Lys9 was devoid of any detectable L‐alanine and L‐lactate synthesis.</P><P><B>CONCLUSION</B></P><P>Superior to classical producers to some degree, <I>C. glutamicum</I> Lys9 is more adaptable for industrial L‐lysine production. In addition to L‐lysine, pyruvate, oxaloacetate (OAA) and L‐valine were produced by <I>C. glutamicum</I> Lys9, suggesting further optimization to improve L‐lysine production by engineering the L‐lysine and/or NADPH biosynthetic pathway. © 2013 Society of Chemical Industry</P>