High fermentative production of L-threonine from acetate by a Brevibacterium flavum stabilized strain transformed with a recombinant plasmid carrying the Escherichia coli thr operon.
Decrease in L-threonine productivity caused not only by plasmid-free segregation but also by plasmid deletion was observed in a Brevibacterium flavum L-threonine producer when transformed with a recombinant plasmid carrying Escherichia coli thr operon. However, a recombinant strain, HT-16, was stabilized by the addition of trimethoprim (a selective marker on the vector) at concentration of 1000 micrograms/ml, which was rather higher than the minimum inhibitory one, into the stock culture medium. Strain HT-16 produced 64.4 g/liter of L-threonine, 30% higher than that of the host strain, after 92 h of cultivation in a small jar fermentor using acetic acid as a carbon source without trimethoprim.
Ishida
M
M
Central Research Laboratories of Ajinomoto Co., Inc., Kanagawa, Japan.
Sato
K
K
Hashiguchi
K
K
Ito
H
H
Enei
H
H
Nakamori
S
S
D000085:Acetates / Q000378:metabolism*; D001951:Brevibacterium / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media; D004274:DNA, Recombinant; D004926:Escherichia coli / Q000235:genetics*; D005285:Fermentation / Q000187:drug effects; D005822:Genetic Vectors; D009876:Operon; D010957:Plasmids; D013237:Stereoisomerism; D013912:Threonine / Q000096:biosynthesis*; D014169:Transformation, Bacterial; D014295:Trimethoprim / Q000494:pharmacology
D000085:Acetates; D003470:Culture Media; D004274:DNA, Recombinant; D013912:Threonine; D014295:Trimethoprim