Effective production of single-chain variable fragment (scFv) antibody using recombinant Escherichia coli by DO-stat fed-batch culture.

Dissolved oxygen (DO)-stat fed-batch culture, which allows a high cell density culture of microorganisms under constant DO conditions, was applied to anti-CRP single-chain variable fragment (scFv) production using recombinant Escherichia coli. The DO-stat fed-batch culture was successfully performed under various DO conditions for more than 50 h, resulting in increased scFv production from 0.5 to 0.8 g/L by flask and batch cultures to 2.8–3.0 g/L by the fed-batch culture under the conditions of 5–40% of DO saturation. The formation of inclusion bodies was effectively depressed during DO-stat fed-batch operation; consequently, the solubility of anti-CRP scFv was significantly improved from 36–43% by the flask and batch cultures to 96–98% by the DO-stat fed-batch culture under a wide range of DO conditions. From the kinetic analysis of fed-batch experiments, it was also found that the successful folding of anti-CRP scFv in the cytoplasm occurred when metabolic rates, such as the specific growth rate and specific glucose consumption rate, were relatively low. These results show that the fed-batch culture operated by the DO-stat feeding strategy was effective for the enhanced production of anti-CRP scFv with high solubility.