ASSESSING POSTINDUCTION CELLULAR-RESPONSE IN A RECOMBINANT ESCHERICHIA-COLI LACTOSE-INDUCIBLE SYSTEM BY MONITORING BETA-GALACTOSIDASE LEVELS

A synthetic lactose-inducible promoter was chosen; to study host cell responses to the over-expression of heterologous genes. Fermentations were conducted to compare the effect of induction strategies on the sy nthesis of beta-galactosidase versus the production of recombinant pro tein. The levels of lactose, IPTG and glucose during induction were ma nipulated to adjust the utilization of lactose as the inducer and/or t he carbon source. In addition, the involvement of the gal operon in la ctose metabolism was also explored in order to optimize lactose transp ort and utilization during induction.