Reverse Micelles, Enzymes

Abstract

Reverse micelles or w/o microemulsions have found wide applications in enzymology, protein chemistry and biocatalysis. Biocatalysis based on reverse micelles, is one of the earliest methodologies where microemulsions were introduced to solubilize enzymes in organic solvents. Reverse micelles have been associated to the idea of a microreactor where the enzyme can be sheltered and protected from solvent detrimental effects providing a unique microenvironment for the enzymes to react with water insoluble or poorly soluble substrates present in the organic phase. The most often investigated enzymes in microemulsions are lipases, because these enzymes are very stable and active in this medium. This review focuses on the fundamental aspects of enzymes encapsulation in reverse micelles, as well as on biotechnological applications based on these systems as reaction media for biotransformations using mainly lipase‐catalyzed processes.

Ultrasonic Characterisation of W/O Microemulsions - Structure, Phase Diagrams, State of Water in Nano-Droplets, Encapsulated Proteins, Enzymes

“…We can speculate that an alternative reaction is related to transglycosylation activity of some of -glucosidases resulting in production of tri-and tetrasaccharides. The activity can be enhanced by immobilisation and limited hydration (example: Chen & Ou-Yang, 2004;Marico et al, 2001), which are well known factors affecting functioning of enzymes in microemulsions (Kolisis & Stamatis, 2010). This could explain the observed decrease in ultrasonic velocity.…”

“…One of the possible explanations of lower than expected compressibility of encapsulated protein could be an effect of confine environment on the mechanical properties of protein globule, which can restrict the mobility of protein segments, thus making it more rigid (F. N. Kolisis & Stamatis, 2010). This will reduce the values of Tsp k and Ssp k in Equations (12) and (14) therefore the total compressibility of protein measured in microemulsion, Ssp k .…”

Ultrasonic Monitoring of Biocatalysis in Solutions and Complex Dispersions

“…However, water is often a poor solvent for applications in synthetic and industrial chemistry [67]. Water-in-oil microemulsions (w/o ME) provide a favorable hydrophilic environment for enzyme activity [68].…”

“…Water-in-oil microemulsions (w/o ME) provide a favorable hydrophilic environment for enzyme activity [68]. In addition to this, the confined environment inside the ME droplets affects the mobility of the enzyme atomic groups and their hydration level, which can be applied for changing/controlling the enzymatic catalytical activity [67]. Examples of applications of microemulsions for enzyme catalysis of reactions include hydrolytic and reverse hydrolytic reactions, esterifications and transesterifications, resolution of racemic amino acids, oxidation and reduction of steroids, and synthesis of phenolic and aromatic amine polymers [68].…”

Confined Pool-Buried Water-Soluble Nanoparticles from Reverse Micelles

“…Reverse micelles (RMs) are aggregates of surfactant molecules with their hydrophilic heads concentrated in the interior and their hydrophobic tails exposed to the oil continuum. As depicted in Figure , one of the most distinctive features of RMs is their confined water pools surrounded by the amphiphilic monolayer, in which the water molecules demonstrate properties that are remarkably different from those observed in bulk water. , Only as the water-to-surfactant molar ratio ( W 0 ) reaches a certain critical value (e.g., W 0 > 8 for AOT surfactant), the properties of the water pool asymptotically approach those of pure water. But even at relatively large W 0 values, small differences remain still.…”