Deep eutectic solvents as novel extraction media for protein partitioning

Area of Science:

• Green Chemistry
• Bioseparation Engineering
• Protein Purification

Background:

• Ionic liquid-based aqueous two-phase systems (IL-based ATPS) are effective for protein extraction but raise environmental concerns.
• Deep eutectic solvents (DES) present a greener, cost-effective alternative with tunable properties for bioseparation.

Purpose of the Study:

• To synthesize and evaluate green deep eutectic solvents (DES) for extracting bovine serum albumin (BSA) using an aqueous two-phase system (ATPS).
• To optimize extraction conditions and investigate the mechanism of BSA separation.
• To assess the potential of DES-based ATPS as a sustainable substitute for IL-based ATPS in protein purification.

Main Methods:

• Synthesis of four green DES, including choline chloride (ChCl)-urea.
• Optimization of BSA extraction using ChCl-urea DES in an ATPS via single-factor and orthogonal experiments.
• Analysis of extraction efficiency, protein integrity (UV-vis, FT-IR, CD spectra), and separation mechanism (conductivity, DLS, TEM).

Main Results:

• Optimal conditions yielded high BSA extraction efficiencies (up to 100.05%) with excellent precision, repeatability, and stability.
• Spectroscopic and structural analyses confirmed no chemical interaction or conformational changes in BSA during extraction.
• Hydrophobic interactions, hydrogen bonding, and salting-out effects, along with aggregation, were identified as key separation drivers.

Conclusions:

• Choline chloride-urea DES-based ATPS is highly effective and selective for BSA extraction, preserving protein integrity.
• DES-based ATPS offer a promising, environmentally friendly alternative to traditional IL-based systems for protein purification.
• This study opens new avenues for sustainable bioseparation processes in the pharmaceutical and biotechnology industries.