Recovery of recombinant proteins from plants using aqueous two-phase partitioning systems: an outline

Transgenic plants producing recombinant proteins are a potential low-cost substitute for complex bioreactors. However, the development of new robust downstream processes to improve protein recovery and isolation from plant feedstock is critical to promote this new technique because downstream processing costs typically contribute to more than 80 % of the total cost. Polishing separation platforms for protein purification, such as chromatography and membrane filtration, have been well established, while little attention has been allocated to initial concentration and separation procedures. In this chapter, application of aqueous two-phase partitioning (ATPP), as an attractive alternative to traditional processes for recovering and isolating target proteins from plant green tissues or seeds, as well as the main advances reported in literature concerning ATPP for the isolation and purification of proteins from plant feedstock are reviewed. The potential application of ATPP as an integrated extraction and isolation step and isolation step after extraction or protein characterization method is discussed separately. The connection of ATPP with traditional protein separation processes is discussed. The separation mechanisms of ATPP are explained based on surface properties of proteins and polymer systems. Finally, the future trends in applying ATPP for protein separation are discussed.