Histidine tagged protein recovery from tobacco extract by foam fractionation.

Tobacco plants have the potential to be used for the production of proteins for pharmaceutical applications. This work describes a novel protein recovery strategy where the protein of interest is "tagged" with a histidine sequence, which forms a complex with cobalt ions and surfactant possessing a chelating functionality, such that the protein is recovered in the foamate of a foam fractionation step. His-gus, a histidine-tagged enzyme, was chosen as a model protein to study the feasibility of this strategy. The His-gus is recovered from spiked prefoamed tobacco extract by foam fractionation in the presence of surfactant and cobalt ions with an enrichment of 1.29 and a recovery of 21.5% in terms of an adjusted activity.