Extraction of some essential amino acids using aqueous two-phase systems made by sugar-based deep eutectic solvents

Aqueous two-phase systems (ATPSs) have long been recognized as versatile and efficient tools for the extraction of biomolecules, including amino acids. Recent advancements in the field have introduced a novel approach by utilizing deep eutectic solvents (DES) to form ATPs. This study aimed to determine the phase diagrams for an ATPS made of polyethylene glycol dimethyl ether 250 and two types of NADESs, namely choline chloride as a hydrogen bond acceptor (HBA), and either sucrose or fructose as a hydrogen bond donor (HBD) with a molar ratio of 1 : 2. The measured tie-line results revealed that the hydrogen bonds of NADES may not be entirely disrupted in aqueous solutions, and thus, these ATPSs act as ternary-like systems. Additionally, the binodal data were fitted using two semi-empirical equations, namely Merchuk and Zafarani-Moattar et al. equations. Furthermore, the ATPSs mentioned above were applied to extract three amino acids, namely l-arginine, l-phenylalanine, and l-tyrosine, and demonstrated good extraction levels. Finally, the Diamond-Hsu equation and its modified version were utilized to correlate the experimental partition coefficients of the amino acids. These advancements pave the way for the development of improved extraction methodologies and the exploration of new applications in the field of biotechnology, pharmaceuticals, and beyond.

Automated summary

This study developed a novel aqueous two-phase system (ATPS) using deep eutectic solvents (DES) combined with polyethylene glycol dimethyl ether 250 and two types of NADESs. The experimental results showed that the hydrogen bonds of NADESs in the mixed solutions may not be completely disrupted, forming ternary-like systems. Additionally, the binodal data fitted well using the Merchuk and Zafarani-Moattar equations. Furthermore, the ATPSs demonstrated good extraction levels for amino acids such as l-arginine, l-phenylalanine, and l-tyrosine. These findings provide a basis for the development of improved extraction methodologies and exploring new applications in biotechnology and pharmaceuticals.