The effect of cellular energetics on foreign protein production

Escherichia coli strain F-122 was used to determine if there are additional physiological effects, other than decreasing energetic efficiency accompanied by the excretion of the acetate, on foreign protein production. This organism was the host for expressing HIV₅₈₂-β-galactosidase fusion protein under the control of thetrp promoter, with ampicillin resistance. By comparing parallel batch cultures with and without acetate addition, it was found that the presence of acetate in the media did not influence β-galactosidase activity. In these experiments, it appears that the low protein productivity often observed during acetate formation is the result of inefficient cell metabolism, rather than acetate acting as a specific inhibitor of protein production.