Exploring the Potential of PEG-Based Deep Eutectic Solvents as a Sustainable Alternative for Extraction of Biological Macromolecules Bovine Serum Hemoglobin.

In recent years, deep eutectic solvents (DESs) have garnered significant attention as promising green alternatives to conventional organic solvents for a wide range of applications. In this study, four novel polyethylene glycol (PEG)-based DESs were prepared and evaluated for their physicochemical properties, including density, dynamic viscosity, and kinematic viscosity. Fourier transform infrared spectroscopy (FT-IR) and NMR analyses revealed substantial intermolecular interactions between the hydrogen bond donor and hydrogen bond acceptor components, confirming the formation of stable DES systems. The application of the prepared DESs was tested in biological separation, specifically for the selective extraction of bovine serum hemoglobin (BHb). This study demonstrates the efficacy of PEG-based DESs in selectively extracting BHb. Among the DESs studied, DES-4 (PEG-600) achieved the highest extraction efficiency of 88%, while maintaining protein stability. Spectroscopic techniques, including UV-visible, fluorescence, dynamic light scattering, circular dichroism, and FT-IR, were employed to investigate the extraction mechanism, conformational changes in protein structure, and DES-protein interactions. These methods provided insights into the structural stability and functionality of BHb during the extraction process. The physicochemical characterizations confirmed the unique properties of PEG-based DESs, making them viable candidates for sustainable protein extraction. Their compatibility, excellent extraction efficiency, and short separation times underscore their potential as environmentally friendly and long-lasting substitutes for conventional separation techniques. This study highlights the advancement of DESs in green chemistry and biotechnological applications, offering an efficient and sustainable platform for protein extraction while maintaining structural integrity.