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Published on: August 6, 2018
Aqueous two-phase extraction for protein recovery from corn extracts
Zhengrong Gu1, Charles E Glatz
1Department of Chemical and Biological Engineering, 2114 Sweeney Hall, Iowa State University, Ames, IA 50011-2230, USA.
Summary
Aqueous two-phase partitioning effectively purifies recombinant proteins from corn, optimizing recovery and concentration. This method integrates biomass removal, offering a cost-effective solution for large-scale production challenges.
Area of Science:
- Biotechnology
- Biochemical Engineering
- Protein Purification
Background:
- Corn is a promising host for large-scale recombinant protein production.
- Efficient downstream processing, including initial recovery, separation, and concentration, remains a significant challenge.
- Aqueous two-phase (ATP) partitioning offers advantages for integrating biomass removal with protein recovery and concentration from fermentation broths.
Purpose of the Study:
- To evaluate the applicability of ATP partitioning for purifying recombinant proteins from corn endosperm and germ.
- To optimize ATP system parameters (PEG MW, salt, TLL, pH) for controlled protein partitioning.
- To assess the integration of protein extraction with partitioning for improved purification efficiency.
Main Methods:
- ATP systems were developed using varying poly(ethylene glycol) (PEG) molecular weights (MW), phase-forming salts, tie line lengths (TLL), and pH.
- Partitioning of extracted native proteins and model proteins (lysozyme, cytochrome c) from corn endosperm and germ was analyzed.
- Integrated protein extraction and partitioning steps were compared to traditional separate methods.
Main Results:
- Moderate PEG MW, reduced phase ratio, and added NaCl enabled complete recovery and ~5x enrichment of hydrophobic lysozyme in the top phase.
- Integrated extraction and partitioning reduced host protein contamination compared to separate steps.
- Lower PEG MW and specific salt conditions (1450 PEG, 8.5% NaCl) achieved 5-9x enrichment for hydrophilic cytochrome c in the lower phase.
Conclusions:
- ATP partitioning is a viable method for recovering and concentrating recombinant proteins from corn.
- Optimization of PEG MW and salt composition is crucial for targeting specific protein hydrophobicities and achieving high enrichment.
- Integrated processing shows potential but can be limited by solids loading or protein solubility, necessitating careful system design.
