Process for L-amino acid production using enterobacteriaceae with over-expression of ptsG gene

1. A process for the preparation of L-amino acids in Enterobacteriaceae , comprising

(a) fermenting, in a medium, Enterobacteriaceae which produce L-amino acid and in which the ptsG gene from Escherichia coli coding for glucose-specific IIBC component of the phosphotransferase system is over-expressed by placing the ptsG gene under a potent promoter,

(b) concentrating the L-amino acids in the medium or in the Enterobacteriaceae , and

(c) quantifying the L-amino acids.

2. The process according to claim 1 , which further comprises increasing, in the Enterobacteriaceae , expression of a gene of the biosynthesis pathway of the L-amino acids.

3. The process according to claim 1 , which further comprises reducing or eliminating, in the Enterobacteriaceae , expression of a gene of the metabolic pathway which reduces the amount of the L-amino acids.

4. The process according to claim 1 , wherein the amount of the ptsG gene product is increased.

5. The process according to claim 1 , wherein, expression of at least one gene selected from the group consisting of:

(a) a thrABC operon which encodes aspartate kinase, homoserine dehydrogenase, homoserine kinase and threonine synthase,

(b) a pyc gene which encodes pyruvate carboxylase,

(c) a pps gene which encodes phosphoenol pyruvate synthase,

(d) a ppc gene which encodes phosphoenol pyruvate carboxylase,

(e) a pntA and pntB genes encode for transhydrogenase,

(f) a rhtB gene which imparts homoserine resistance,

(g) a mqo gene which encodes malate:quinone oxidoreductase,

(h) a rhtC gene which imparts threonine resistance,

(i) a thrE gene which encodes the threonine export protein,

(j) a gdhA gene which encodes glutamate dehydrogenase,

(k) a hns gene which encodes the DNA-binding protein HLP-II,

(l) a lrp gene which encodes the regulator of the leucine Lrp regulon,

(m) a pgm gene which encodes phosphoglucomutase,

(n) a fba gene which encodes the fructose bisphosphate aldolase,

(o) a dps gene which encodes the global regulator DPS,

(p) a ptsH gene which encodes the phosphohistidine protein hexose phosphotransferase,

(q) a ptsI gene which encodes enzyme I of the phosphotransferase system,

(r) a crr gene which encodes the glucose-specific IIA component,

(s) a mopB gene which encodes chaperone GroES,

(t) a ahpC gene which encodes the small sub-unit of alkyl hydroperoxide reductase, and

(u) a ahpF gene which encodes the large sub-unit of alkyl hydroperoxide reductase, is increased.

6. The process according to claim 5 , wherein the ptsG gene and the fba gene are over-expressed.

7. A process according to claim 1 , wherein, expression of at least one gene selected from the group consisting of:

(a) a tdh gene which encodes threonine dehydrogenase,

(b) a mdh gene which encodes malate dehydrogenase,

(c) a gene product of the open reading frame (orf) yjfA,

(d) a gene product of the open reading frame (orf) ytfp,

(e) a pckA gene which encodes phosphoenol pyruvate carboxykinase,

(f) a poxB gene which encodes pyruvate oxidase,

(g) a aceA gene which encodes isocitrate lyase,

(h) a dgsA gene which encodes the DgsA regulator of the phosphotransferase system,

(i) a fruR gene which encodes the fructose repressor, and

(j) a rpoS gene which encodes the sigma 38 factor is reduced.

8. The process according to claim 1 , further comprising:

(c) isolating the L-amino acids.

9. The process according to claim 8 , wherein at least a portion of constituents of the medium and/or a biomass resulting from fermenting remain with the isolated L-amino acids.

10. The process according to claim 1 , wherein the L-amino acids are L-threonine.

11. The process according to claim 1 , which further comprises increasing the copy number of the ptsG gene.