| 摘要 |
PURPOSE:To obtain a transformed microbial strain having high L-tryptophan productivity, by preparing a DNA molecule having a segment composed of mutually linked plural DNA fragments containing genetic information participating in biosynthesis of L-tryptophan and inserting the DNA molecule in a specific host microorganism. CONSTITUTION:The host cell is a microorganism belonging to Bacillus genus preferably resistant to tryptophan analogue. For example, plasmid pSD2961 is partially cut with a restriction enzyme HindIII and linked again with T4- phage ligase. E.coli C600 treated with calcium chloride is transformed with the obtained DNA by conventional method. A tryptophan-nonrequiring, ampicillin-resistant and tetracycline-sensitive transformant is selected from the transformed E.coli and a plasmid pSD3171 is separated from the transformant by conventional separation and purification technique. The objective transformed microbial strain can be produced therefrom. |
