| abstract |
An Escherichia coli chromosomal DNA segment is engineered for controllable excision and loss from the E. coli cell population. The DNA segment has a gene determining a function that is lost in the absence of that chromosomal segment. Specifically, the segment includes a pair of lambdoid phage att sites positioned at opposite ends thereof, and a gene encoding the function. The E. coli cell includes DNA encoding lambdoid phage int and xis, positioned for transcription under control of an external stimulus. By excising the chromosomal DNA segment once a desired cell population is achieved, cell growth and diversion of intermediates from a desired fermentation product are diminished or avoided. |