| 摘要 |
PURPOSE:To obtain the subject gene DNA, isolated from a coryneform bacterium such as Brevibacterium.flavum MJ-233, having a specific base sequence and capable of providing a transformant remarkably improved in productivity of L-isoleucine, L-valine, etc. CONSTITUTION:Brevibacterium.flavum MJ-233 which is a corynebacterium is cultured in a culture medium till the latter period of the logarithmic growth phase and the microbial cell is collected and suspended in a buffer solution containing a lysozyme. Protenase K(R) and sodium dodecyl sulfate are then added to carry out the lysis. The resultant lysate is subsequently extracted with a phenol/chloroform solution. Ethanol is added to the extract solution to recover a DNA, which is then treated with a restriction enzyme, bound to a cloning vector and inserted into Escherichia coli to perform transformation. The obtained transformant is subsequently cloned to sort out a positive clone. A plasmid is recovered from the obtained strain and treated with a restriction enzyme to afford the objective gene DNA, capable of coding an acetohydroxy acid synthase derived from the coryneform bacterium and expressed by the formula, etc. |
