Co-operative effects of protein engineering and vector optimization on high yield expression of functional bivalent miniantibodies in Escherichia coli

The volumetric yield of functional phosphocholine-binding miniantibodies co uld be increased in E. coli fermentations by the combination of the followi ng approaches: Firstly, mini-antibody mutants with amino acid exchanges in the V-H chain leading to improved folding were expressed. Secondly, the exp ression vector was stabilized by an efficient suicide system to prevent pla smid loss. Thirdly, the cells were grown to high cell densities in a stirre d tank reactor.