Genetic breeding of L-tyrosine producer from Brevibacterium lactofermentum.
A wild-type parent of Brevibacterium lactofermentum was converted into an L-Tyr producer by three steps of genetic breeding. First, acquirement of m-fluoro-D, L-phenylalanine resistance (1,000 microgram/ml) brought about MF1317 which produced 3.5 g/l of L-Tyr and a byproduct of 2.8 g/l of L-Phe. Second, increase in the drug resistance (5,000 microgram/ml) gave MF358 that produced 6.4 g/l of L-Tyr and a byproduct of 6.0 g/l of L-Phe. Third, an L-Phe auxotrophic mutant (FT-1) derived from MF358 accumulated 16 g/l of L-Tyr. In FT-1, L-Phe was not accumulated at all, but a small amount of anthranilate (0.4 g/l) was. A key enzyme in the biosynthesis of L-Tyr, 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase, was free from synergistic feedback inhibition by L-Tyr and L-Phe in the producers, and so L-Tyr accumulation occurred independently of L-Phe concentration in the production medium.
Ito
H
H
Central Research Laboratories, Ajinomoto Co., Inc., Kawasaki, Japan.
Sakurai
S
S
Tanaka
T
T
Sato
K
K
Enei
H
H
D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000378:metabolism; D000596:Amino Acids / Q000494:pharmacology; D001951:Brevibacterium / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D004352:Drug Resistance, Microbial; D007700:Kinetics; D009154:Mutation; D010641:Phenotype; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000494:pharmacology; D014443:Tyrosine / Q000096:biosynthesis*
D000596:Amino Acids; D014443:Tyrosine; C027218:3-fluorophenylalanine; D010649:Phenylalanine; D010723:3-Deoxy-7-Phosphoheptulonate Synthase