Effective Release of Intracellular Enzymes by Permeating the Cell Membrane with Hydrophobic Deep Eutectic Solvents

Abstract

An efficient and green method is crucial for the recovery of intracellular biological products. The major drawbacks of the conventional cell disruption method are nonselectivity and enzyme denaturation. The permeability of hydrophobic deep eutectic solvents (DESs) to the cell membrane was studied, for the first time, and then hydrophobic DESs were innovatively applied to release intracellular enzymes from recombinant Escherichia coli. After optimization, a DES suspension of l‐menthol/oleic acid (0.5 %, v/v) showed the highest release yield of intracellular enzyme. Compared with that released by sonication, a release yield of phospholipase D (PLD) of up to 114.58 % was achieved, and the specific activity was increased by 1.96 times. The microstructure of the cell membrane under different treatments was observed by using an electron microscope to understand the permeation of DESs to the cell membrane. The feasibility and applicability of the proposed release method in industrial applications were also demonstrated. The effective and green release method of intracellular enzymes developed herein has bright prospects for industrial application to replace traditional cell disruption methods. A preliminary study on the permeability of hydrophobic DESs to the cell membrane showed that there would be a potential application prospect of hydrophobic DESs not only in releasing intracellular contents, but also in seeking new green penetrating agents.

Improvement of Conversion Efficiency from d-Glucose to d-Allulose by Whole-Cell Catalysts with Deep Eutectic Solvents

“…The cells were transparent and empty after the component penetration and diffusion in the medium, indicating that DES increased the cell membrane permeability and motivated the efflux of cytoplasmic substances. Cao’s study also showed that the cell membrane was partially damaged by a hydrophobic DES, which was similar to the present results . The E.…”

“…Cao's study also showed that the cell membrane was partially damaged by a hydrophobic DES, which was similar to the present results. 44 The E. coli cell wall consists of two membranes: the outer layer is comprised of lipopolysaccharides, and the inner layer is a phospholipid bilayer. 45 An investigation of the interaction between a DES and a cell indicated that the HBD inserted in the phospholipid bilayer and that the insertion was dependent on the hydrophobicity of HBDs.…”

Antibacterial and antifungal activities of natural deep eutectic solvents

“…5 TEM images of Escherichia coli cells before any treatment A and after treatment with a suspension of L-menthol/oleic acid, 1:1. With the permission of Cao et al ( 2020 ) …”

Natural deep eutectic solvents (NaDES): translating cell biology to processing

“…Poorly water-soluble compounds can be extracted from plant biomass in high concentrations and afterwards separated from the (Na)DES by addition of water and subsequent compound precipitation. Thus, (Na)DES, alone or in combination with other methods, can be used to extract various compounds like polyphenols, 47–51 pigments, 52 enzymes 53 and carbohydtrates. 50 Their high solubilizing capacity can be exploited to overcome limited substrate solubility in enzymatic reactions 54 as well as for separation techniques.…”