Method of regulating expression of a foreign gene by controlling the sugar concentration in a medium and a process of producing a foreign gene product thereby

Abstract From the Canadian patent

Escherichia coli carrying a hybrid plasmid having been constructed by inserting a desired foreign gene into an expression vector so as to permitting expression of said desired foreign gene therein was cultured in a medium containing a sugar component utilizable by the E. coli as a carbon source at a concentration of 0.3% or more so that the expression of said desired foreign gene was suppressed. This E. coll (i.e. transformant) was cultured in the medium in which the sugar concentration was maintained at 0.3%or more in a first process so as to supress the suppression of the foreign gene and to support sufficient cell growth and thereafter at less than 0.3% in a second process to release the …