The use of dissolved oxygen-controlled, fed-batch aerobic cultivation for recombinant protein subunit vaccine manufacturing.

A simple "off-the-shelf" fed-batch approach to aerobic bacterial cultivation for recombinant protein subunit vaccine manufacturing is presented. In this approach, changes in the dissolved oxygen levels are used to adjust the nutrient feed rate (DO-stat), so that the desired dissolved oxygen level is maintained throughout cultivation. This enables high Escherichia coli cell densities and recombinant protein titers.

Investigation into the misincorporation of norleucine into a recombinant protein vaccine candidate.

A high level of norleucine misincorporation was detected in a recombinant methionine-rich protein vaccine candidate expressed in E. coli K12. An investigation was conducted to evaluate a simple remediation strategy to reduce norleucine misincorporation and to determine if the phenomenon was either (a) due to the depletion of methionine during fermentation, (b) a result of the cultivation environment, or (c) a strain-specific effect.

Development of a scaled-down aerobic fermentation model for scale-up in recombinant protein vaccine manufacturing.

A simple approach to the development of an aerobic scaled-down fermentation model is presented to obtain more consistent process performance during the scale-up of recombinant protein manufacture. Using a constant volumetric oxygen mass transfer coefficient (k(L)a) for the criterion of a scale-down process, the scaled-down model can be "tuned" to match the k(L)a of any larger-scale target by varying the impeller rotational speed. This approach is demonstrated for a protein vaccine candidate expressed in recombinant Escherichia coli, where process performance is shown to be consistent among 2-L, 20-L, and 200-L scales.