Genetic Breeding of L-Tyrosine Producer from Brevibacterium lactofermentum(Microbiology & Fermentation Industry)

概要

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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 (1,000μg/ml) brought about MF1317 which produced 3.5g/l of L-Tyr and a byproduct of 2.8g/l of L-Phe. Second, increase in the drug resistance (5,000μg/ml) gave MF358 that produced 6.4g/l of L-Tyr and a byproduct of 6.0g/l of L-Phe. Third, an L-Phe auxotrophic mutant (FT-1) derived from MF358 accumulated 16g/l of L-Tyr. In FT-1, L-Phe was not accumulated at all, but a small amount of anthranilate (0.4g/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.
社団法人日本農芸化学会の論文
1990-03-23