OPTIMIZATION OF STARTING TIME AND PERIOD OF INDUCTION AND INDUCER CONCENTRATION IN THE PRODUCTION OF THE RESTRICTION ENZYME ECORI FROM RECOMBINANT ESCHERICHIA-COLI-294

Induction parameters including inducer concentration; period of induct ion and the cell concentration at which inducer is to be added to the fermentation broth were optimized in order to increase the yield of th e EcoRI restriction endonuclease isolated from recombinant E. coli. Ba cterial cells harboring the plasmid pPG430 containing EcoRI endonuclea se and the methylase genes under the control of lac promoter were used in the experiments where induction was accomplished by using lactose isopropyl-beta-D-thiogalactoside (IPTG). An IPTG concentration of 0.1 mM, the late exponential phase of growth (at an optical density of 1.2 at 595 nm) and an induction period of 6 hours were determined to be t he optimum conditions for induction.