摘要:
An essentially pure plasmid is provided, which is characterized by a molecular weight of 1.8 megadalton and the restriction endonuclease-cleavage chart shown in the Figure, and which is capable of propagating in a Coryneform glutamic acid producing bacterium as a host strain. This plasmid may be inserted by a gene which is responsible for the production of a product and the hybrid plasmid may be incorporated in Coryneform glutamic acid producing bacteria as recipient organisms.
摘要:
New L-threonine-producing strains of the genus Brevibacterium and Corynebacterium are obtained by separating a plasmid DNA from a microorganism of the genus Brevibacterium and Corynebacterium, inserting into the plasmid DNA a fragment of chromosomal DNA derived from a DNA-donor strain of the genus Brevibacterium or Corynebacterium resistant to a-amino-p-hydroxy valeric acid to obtain a recombinant plasmid DNA, incorporating the recombinant plasmid DNA into a recipient strain of the genus Brevibacterium or Corynebacterium which is sensitive to α-amino-β-hydroxy valeric acid and isolating a strain transformed to become resistant to α-amino-β-hydroxy-valeric acid. By aerobically cultivating the new strains in an aqueous culture medium L-threonine may be obtained in high yields.
摘要:
L-histidine producing microorganisms are constructed by incorporating, into a recipient strain of the genus Bacillus, a recombinant plasmid containing a DNA fragment controlling resistance to a histidine-antagonist, which DNA fragment is obtained from chromosomal DNA of a mutant of the genus Bacillus resistant to the histidine-antagonist.
摘要:
New L-threonine-producing strains of the genus Brevibacterium and Corynebacterium are obtained by separating a plasmid DNA from a microorganism of the genus Brevibacterium and Corynebacterium, inserting into the plasmid DNA a fragment of chromosomal DNA derived from a DNA-donor strain of the genus Brevibacterium or Corynebacterium resistant to a-amino-p-hydroxy valeric acid to obtain a recombinant plasmid DNA, incorporating the recombinant plasmid DNA into a recipient strain of the genus Brevibacterium or Corynebacterium which is sensitive to α-amino-β-hydroxy valeric acid and isolating a strain transformed to become resistant to α-amino-β-hydroxy-valeric acid. By aerobically cultivating the new strains in an aqueous culture medium L-threonine may be obtained in high yields.
摘要:
L-cysteine is produced by culturing an Escherichia bacterium having L-cysteine producing ability and containing a gene encoding an O-acetylserine sulphydrylase B or MalY regulatory protein that is modified so that cysteine desulfhydrase activity is reduced or eliminated. The bacterium is cultured in a medium to produce and cause accumulation of L-cysteine in the medium, and collecting L-cysteine from the medium.
摘要:
L-cysteine is produced by culturing an Escherichia bacterium having L-cysteine producing ability and containing a gene encoding an O-acetylserine sulphydrylase B or MalY regulatory protein that is modified so that cysteine desulfhydrase activity is reduced or eliminated. The bacterium is cultured in a medium to produce and cause accumulation of L-cysteine in the medium, and collecting L-cysteine from the medium.
摘要:
An L-valine-producing microorganism which is constructed by incorporation into a host strain of the genus Escherichia of a hybrid plasmid having inserted therein a DNA fragment with genetic information related to L-valine production which is derived from a donor strain of the genus Escherichia which is resistant to a valine analogue, is useful for the production of high levels of L-valine by fermentation.
摘要:
A process for producing L-tryptophan in which a suitable substrate such as a carbohydrate, indole or anthranilic acid is contacted with Coryneform bacteria, where the Coryneform bacteria bear recombinant DNA constructed by connecting a gene coding for tryptophan synthetase with a plasmid vector capable of proliferating in Coryneform bacteria.