As one of the essential amino acids, L-valine plays an important role in physiology and biochemistry. Pyruvate is not only the precursor needed for L-valine biosynthesis, but also an important intermediate metabolite. Therefore, the efficient accumulation of L-valine and cell growth are mutually affected. In order to keep balance between cell growth and accumulation of L-valine, the CRISPR interference technique for Corynebacterium glutamate was established, and the relative transcription levels of several genes in tricarboxylic acid cycle (TCA) and pentose phosphate pathway (PPP) were regulated in varying degrees. Through shaking flask experiment, the genes aceE encoding pyruvate dehydrogenase and Cgl1576 encoding glucose-6-phosphate dehydrogenation were confirmed as effective modification targets for L-valine accumulation. When the initiation of aceE and Cgl1576 were weakened, 34.6 and 32.3 g/L L-valine were accumulated, which were 6.1 and 3.8 g/L higher than the control, respectively. In addition, it was confirmed that weakening the initiation of aceE and Cgl1576 was the best interference strategy, with a final L-valine accumulation of 37.1 g/L. This study not only determined important target genes for modification, but also provided a new direction for accumulation of L-valine in C.glutamate.
DU Lihong
,
XIONG Haibo
,
XU Da
,
XU Qingyang
,
CHEN Ning
. Construction of L-valine production strain by CRISPRi system of Corynebacterium glutamicum[J]. Food and Fermentation Industries, 2020
, 46(17)
: 1
-8
.
DOI: 10.13995/j.cnki.11-1802/ts.024241
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