Transductional construction of a threonine-hyperproducing strain of Serratia marcescens: lack of feedback controls of three aspartokinases and two homoserine dehydrogenases.
AUTOR(ES)
Komatsubara, S
RESUMO
To construct a threonine-hyperproducing strain of Serratia marcescens Sr41, the six regulatory mutations for three aspartokinases and two homoserine dehydrogenases were combined in a single strain by three transductional crosses. The constructed strain, T-1026, carried the lysC1 mutation leading to lack of feedback inhibition and repression of aspartokinase III, the thrA1(1) mutation desensitizing aspartokinase I to feedback inhibition, the thrA2(1) mutation releasing feedback inhibition of homoserine dehydrogenase I, the two hnr mutations derepressing aspartokinase I and homoserine dehydrogenase I, and the etr-1 mutation derepressing aspartokinase II and homoserine dehydrogenase II. The strain produced ca. 40 mg of threonine per ml of medium containing sucrose and urea. Furthermore, the productivity of strain T-1026 was compared with those of strains devoid of more than one of the six regulatory mutations.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=242483Documentos Relacionados
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