Abstract:

The mutant strain N3-10 mutagenized by Corynebacterium pekinense AS1.299 as starting strain was screened with the flat plate which con
tained leucine, norleucine or ethionine in turn to obtain high yield methioninemutant strains L3,LN7 or E31.Determined inhibiting concentration of leucine to mutant strain N3-10 was 8 g/L, the inhibiting concentration of norleucine to mutant strain L3 was 3 g/L, the inhibiting concentration of ethionine to mutant strain LN7 was 3 g/L. After UV mutagenesis and screening by three methionine analogues, the obtained E31 mutant strain resistant to ethionine can generate methionine 1.479 g/L, which is higher by 0.379 g/L compared with N3-10 prototroph strain generated methionine after fermentation. It was shown that go down to 5th posterity had good genetic stability.

Key words: methionine； analogue； mutant, screening