Extraction of proteins with ionic liquid aqueous two-phase system based on guanidine ionic liquid

Area of Science:

• Green Chemistry
• Biochemistry
• Separation Science

Background:

• Ionic liquids (ILs) are versatile solvents with tunable properties.
• Aqueous two-phase systems (ATPS) are effective for biomolecule separation.
• Developing sustainable and efficient protein extraction methods is crucial.

Purpose of the Study:

• To synthesize and evaluate green ionic liquids for protein extraction.
• To develop and optimize an ionic liquid aqueous two-phase system (ILATPS) for bovine serum albumin (BSA) extraction.
• To investigate the extraction mechanism and protein stability.

Main Methods:

• Synthesis of eight green ionic liquids.
• Development of a guanidine ionic liquid-based ATPS using 1,1,3,3-tetramethylguandine acrylate (TMGA).
• Optimization of extraction conditions using single factor and orthogonal experiments.
• Analysis of extraction efficiency, precision, repeatability, and stability.
• Characterization of protein-IL interactions and conformation using UV-vis and FT-IR.
• Investigation of microstructure and separation mechanism using conductivity, DLS, and TEM.

Main Results:

• An ILATPS based on TMGA guanidine ionic liquid was successfully developed.
• Optimum conditions yielded a high BSA extraction efficiency of 99.6243%.
• Extraction process showed high precision (RSD 0.8156%), repeatability (RSD 1.6173%), and stability (RSD 1.6292%).
• No chemical interactions or conformational changes were observed between BSA and the ionic liquid.
• Hydrophobic interaction, hydrogen bonding, and salting-out effects were key to the separation mechanism.

Conclusions:

• Guanidine ionic liquid-based ATPSs are highly efficient for protein extraction.
• The developed ILATPS offers a promising, green alternative for protein separation.
• The extraction mechanism involves physical interactions and aggregation phenomena, preserving protein structure.