Enzymatic Catalysis at Interfaces—Heterophase Systems as Substrates for Enzymatic Action

Abstract

Several important enzymatic reactions occurring in nature, such as, e.g., the digestion of fat, proceed only at the interface of two immiscible phases. Typically, these systems consist of an organic substrate, dispersed in an aqueous continuous phase, with a specialized enzyme capable of working at the interface. For adopting such a system for organic synthesis, a stable heterophase system with a large interfacial area is required. These prerequisites can be found in so-called miniemulsions. Such liquid-liquid heterophase systems feature droplets with sizes smaller than 500 nm, and more importantly, these emulsions do not suffer from Ostwald ripening, as conventional emulsions do. Consequently, the droplets show long-term stability, even throughout reactions conducted in the droplets. In this review, we will briefly discuss the physicochemical background of miniemulsions, provide a comprehensive overview of the enzymatically catalyzed reactions conducted in miniemulsions and, as data are available, to compare the most important features to conventional systems, as reverse microemulsions, (macro)emulsions and solvent-based systems.

Enzyme-Loaded Mesoporous Silica Particles with Tuning Wettability as a Pickering Catalyst for Enhancing Biocatalysis

“…However, enzymes commonly exhibit activity in the aqueous phase, whilst a majority of substrates can only be soluble in the organic phase. Hence enzymatic reactions tend to happen at the interface of the organic-aqueous biphasic system [3]. Unfortunately, the enzymatic reaction of the biphasic systems is often limited by mass transfer process relying on interfacial area [4].…”

CaLB Catalyzed Conversion of ε-Caprolactone in Aqueous Medium. Part 1: Immobilization of CaLB to Microgels

“…In this case, the hydrolysis-esterification equilibrium can be pushed towards the esterification by using more hydrophobic monomers. In synthetic chemistry the use of miniemulsions as nanoreactors for directing enzymatic catalyzed reactions is a common method, not only for the synthesis of linear aliphatic polyesters [ 20 ], but also for the aminolysis of lactones [ 21 ] or the preparation of biodegradable pentadecalactone (PDL) nanoparticles [ 22 ] among others [ 23 ].…”

Protein engineering of multi-enzyme virus-like particle nanoreactors for enhanced chiral alcohol synthesis

“…These separate them from the rest of the cell, facilitate some specic biochemical activities and play a key role in cellular metabolism. [7][8][9] Inspired by nature, many articial protein cages have been constructed in vitro to localize and control specic chemical reaction processes (Scheme 1). [10][11][12] These proteinaceous compartments can mimic the catalytic environments in cells, and thereby signicantly improve the efficiencies of enzymecatalyzed reactions by enhancing the mass transfer inside the protein cages.…”