Transgenic corn seed for recombinant protein production: relevant aspects on the aqueous extraction of native components

Plants have been considered one of the most promising expression systems for the production of recombinant proteins. Foreseen advantages include high productivity, optimal processing and assembly, and the non‐propagation of human or animal pathogens. A few successful examples of commercial proteins produced in plants have been reported in the literature, such us β‐glucoronidase, avidin, hirudin and aprotinin. Although the purification scheme is always a challenge in downstream processing development, the extraction is the key point since the presence of impurities deleterious to the process efficiency and operational‐life span of the equipment is determined at this step. This work reports the effect of pH and ionic strength in the extraction of proteins, phenolic compounds, lipids and sugars from transgenic corn seed. The phenolic compounds, lipids and reducing sugars were not significantly affected by changes in the ionic strength of the extracting solutions in the range 0–300 mM NaCl and pH 6.3. However, at high pH value (pH 10.0), high solubilization of proteins, phenolic compounds and lipids was achieved, whereas reducing sugars were not significantly extracted at this condition. This work is complementary to the studies reported in a previous paper and contributes to the development of recombinant protein recovery and purification process from transgenic corn.