Solubilization limit of lysozyme into DODMAC reverse micelles

Abstract

Dioctyldimethyl ammonium chloride (DODMAC) was used to form reverse micelles and to extract lysozyme from an aqueous solution into an organic phase. The solubilization behavior of lysozyme into a DODMAC reverse micellar phase was examined in terms of the temperature, the type of cations in the aqueous phase, and the surfactant concentration in the organic phase. Complete removal of lysozyme from the aqueous phase was obtained when the pH was set one unit higher than the pI of the protein. However, it was found that there is a solubilization limit of lysozyme in the organic phase. Not all the lysozyme extracted out of the initial aqueous phase was solubilized into the DODMAC reverse micellar phase, resulting in the formation of white precipitate at the aqueous-organic interface. Temperature has a negligible effect on the solubilization limit of lysozyme. The value of the solubilization limit is a strong function of the type of cations present in the aqueous phase, indicating an important role of lysozyme-cation interactions on the extraction process. An increase in the DODMAC concentration from 100-200 mM resulted in little change in the highest concentration of lysozyme obtained in the organic phase.

Reverse Micellar Extraction and Precipitation of Lysozyme Using Sodium Di(2-ethylhexyl) Sulfosuccinate

“…One mechanism of protein loss, often found in studies of reverse micellar extraction processes, is through the formation of a water‐insoluble protein−surfactant complex that precipitates at the interface between the aqueous and organic phases (37, 38). The formation of this precipitate depended largely on the mass transfer kinetics (39) and on the saturation limit of the protein in the reverse micellar phase (40). The protein−surfactant complex which precipitated at the interface was viewed as an undesirable product, since the protein was thought to be denatured (41).…”

Characterization of reversed micelles of Cibacron Blue F-3GA modified Span 85 for protein solubilization

“…By the presence of the water pools, proteins, enzymes, and nucleic acids can be solubilized into the reversed micellar phase. Thus, a reversed micellar system has been widely studied for potential applications in the field of biotechnology such as protein recovery and purification, enzyme reactions, and protein refolding [2][3][4][5][6][7]. For decades most of the experimental data on protein solubilization by reversed micelles have been collected for systems of ionic surfactants such as bis-2-ethylhexyl sodium sulfosuccinate (AOT) and trioctylmethylammonium chloride (TOMAC) [8][9][10].…”

Novel lipase purification methods – a review of the latest developments

“…1). However, the formation of reverse micelles is proportionally decreased with increasing head group charge, due to the thermodynamically unfavorable electrostatic interactions on hydrophilic sequestration [16].…”