Carbon Nanoparticle-Stabilized Pickering Emulsion as a Sustainable and High-Performance Interfacial Catalysis Platform for Enzymatic Esterification/Transesterification

Abstract

A sustainable and efficient reaction system for enzymatic oil modification is imperative for the food industry. Given the interfacial activation effect of lipase, the sufficient oil–water interface is vital for excellent catalytic activity of lipase. In the present study, a Pickering emulsion reaction system was prepared through directly using reactants as the oil phase and stabilized by mesoporous carbon spheres (MCS) after immobilization of lipase AYS (Candida rugosa, lipase@MCS). Lipase@MCS worked as both the emulsifier and catalyst. Each droplet in the Pickering emulsion was regarded as a microreactor with the reactants in the oil phase, and the removal of the product H2O “pushed” the reaction forward. Taking advantage of the adequate oil–water interface for “lid” opening of lipase and rapid mass transfer in MCS, the Pickering emulsion exhibited excellent enzymatic activity toward phytosterol esterification and transesterification, achieving 95.0% conversion after 1.5 h and catalytic efficiency (CE) of 6.8 mmol g–1 h–1 under nonequilibrium conditions. It is the best performance reported currently with the shortest reaction time, minimal amount of catalyst, and the highest CE (19-fold higher than free lipase one-phase reaction system). Immobilization of lipase on the MCS not only endowed the lipase with exceptional recyclability but also afforded a shield to protect the enzyme from deactivation in a harsh environment, as evidenced by the thermotolerance and recycling test results. This paper paves the way to advancing progress in enzyme-immobilized Pickering emulsion as a sustainable and high-efficiency platform for biocatalysis application.

Responsive Emulsions for Sequential Multienzyme Cascades

“…This stimuli responsiveness allowed the controllable emulsification and demulsification, which were successfully explored for oil recovery [20] and chemocatalysis [21] . However, until now, stimuli‐responsive emulsions for biocatalysis have been relatively underdeveloped, [13c, 22] and to the best of our knowledge, they have never been explored for multienzyme cascades despite their potential to improve reaction compatibility and reduce cross‐reactivity.…”

“…These benefits, especially their large interface, have promoted rapidly the field of "emulsion biocatalysis" to address a wide range of synthetic challenges to date. [10] For instance, microemulsions, [11] miniemulsions, [12] and Pickering emulsions [13] were employed to encapsulate enzymes for the single-step enantioselective reduction, hydrolysis, and esterification. Recently, we further advanced the field by developing multi-compartmentalized emulsion biocatalysis for benzoin condensation and carbonyl reduction.…”

Solvent-free synthesis of phytosterol linoleic acid esters at low temperature

“…1 In recent years, the enzyme-catalyzed synthesis of phytosterol esters has attracted increasing attention as these methods have advantages of having mild and environmentally friendly reaction conditions and fewer side products. 1,[14][15][16][17][18][19][20] However, its high cost and low reliability have great limit its large-scale industrial applications. 1 Previous studies have indicated that the solubility of phytosterol unsaturated fatty acid esters in edible oils (e.g., soybean oil) was up to 10 times than phytosterol saturated fatty acid esters.…”

Engineering proteinaceous colloidosomes as enzyme carriers for efficient and recyclable Pickering interfacial biocatalysis

“…10 Particle-stabilized emulsion, also known as Pickering emulsion, has received considerable interest in biphasic enzymatic catalysis. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] The novel platform combines the advantages of enhanced stability, improved biocompatibility, and ease of product/catalyst separation. 13,14 Given that the involved reactants are organic-soluble, water-in-oil (w/o) Pickering emulsions with oil as the continuous phase are more preferable for feasible extraction of products and reuse of catalysts.…”