초록
<P><B>Background</B></P><P>Oxaloacetate (OAA) and <SMALL>L</SMALL>-glutamate are essential precursors for the biosynthesis of <SMALL>L</SMALL>-lysine. Reasonable control of all potentially rate-limiting steps, including the precursors supply rate, is of vital importance to maximize the efficiency of <SMALL>L</SMALL>-lysine fermentation process.</P><P><B>Results</B></P><P>In this paper, we have rationally engineered the tricarboxylic acid (TCA) cycle that increased the carbon yield (from 36.18 to 59.65%), final titer (from 14.47 ± 0.41 to 23.86 ± 2.16 g L<SUP>−1</SUP>) and productivity (from 0.30 to 0.50 g L<SUP>−1</SUP> h<SUP>−1</SUP>) of <SMALL>L</SMALL>-lysine by <I>Corynebacterium glutamicum</I> in shake-flask fermentation because of improving the OAA and <SMALL>L</SMALL>-glutamate availability. To do this, the phosphoenolpyruvate–pyruvate–oxaloacetate (PEP–pyruvate–OAA) node’s genes <I>ppc</I> and <I>pyc</I> were inserted in the genes <I>pck</I> and <I>odx</I> loci, the P1 promoter of the TCA cycle’s gene <I>gltA</I> was deleted, and the nature promoter of glutamate dehydrogenase-coding gene <I>gdh</I> was replaced by P<SUB>tac-M</SUB> promoter that resulted in the final engineered strain <I>C. glutamicum</I> JL-69P<SUB>tac-M</SUB><I>gdh</I>. Furthermore, the suitable addition of biotin accelerates the <SMALL>L</SMALL>-lysine production in strain JL-69P<SUB>tac-M</SUB><I>gdh</I> because it elastically adjusts the carbon flux for cell growth and precursor supply. The final strain JL-69P<SUB>tac-M</SUB><I>gdh</I> could produce 181.5 ± 11.74 g L<SUP>−1</SUP> of <SMALL>L</SMALL>-lysine with a productivity of 3.78 g L<SUP>−1</SUP> h<SUP>−1</SUP> and maximal specific production rate (<I>q</I><SUB>Lys, max.</SUB>) of 0.73 ± 0.16 g g<SUP>−1</SUP> h<SUP>−1</SUP> in fed-batch culture during adding 2.4 mg L<SUP>−1</SUP> biotin with four times.</P><P><B>Conclusions</B></P><P>Our results reveal that sufficient biomass, OAA and <SMALL>L</SMALL>-glutamate are equally important in the development of <SMALL>L</SMALL>-lysine high-yielding strain, and it is the first time to verify that fed-batch biotin plays a positive role in improving <SMALL>L</SMALL>-lysine production.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (10.1186/s12934-018-0958-z) contains supplementary material, which is available to authorized users.</P>