title: Recombinant trypsin production in high cell density fed-batch cultures in Escherichia coli.
abstract: Fed-batch techniques were employed to obtain high cell density cultures (92-100 g DCW/L) of Escherichia coli strain X90 producing a recombinant serine protease, rat anionic trypsin, secreted to the periplasm. The specific growth rate was controlled to minimize growth-inhibiting acetate formation by utilizing an exponential feeding profile determined from mass balance equation. The volumetric yield of recombinant rat anionic trypsin was 56 mg/L, and the final cell density was 92 g DCW/L when the culture was induced in the late logarithmic phase. However, when the culture was induced in the early logarithmic phase, the volumetric yield was 13 mg/L and the final cell density was 14 g DCW/L. Thus, the induction timing is shown to have a significant effect on the final cell density as well as the overall volumetric yield of the recombinant protease.
authors.affiliation: Department of Chemical Engineering, University of California at Berkeley, Berkeley, California 94702, USA.
authors.forename: L
authors.initials: L
authors.lastname: Yee
authors.forename: H W
authors.initials: HW
authors.lastname: Blanch