Amphiphilic Carbonaceous Microsphere-Stabilized Oil-in-Water Pickering Emulsions and Their Applications in Enzyme Catalysis

An oil-in-water Pickering emulsion system stabilized by amphiphilic porous carbonaceous microspheres was prepared and successfully used in enzyme-catalyzed hydrolysis. The control of the emulsion droplet size and size distribution were investigated by adjusting the particle content and the dispersed phase volume fraction. More than 99 % of the lipase was adsorbed at the interface of the emulsion droplets and showed excellent stability and activity. The size of the emulsion droplets exerted two opposite influences on the catalytic efficiency of the enzyme: increasing the rate of the process by providing a large interfacial area, thereby overcoming mass transfer limitations, and reducing the rate of the process by decreasing the interfacial enzyme concentration. A high hydrolysis yield (up to 100 %) was obtained after 2 h. This study shows the great potential and advantages of using an oil-in-water Pickering emulsion system for enzyme-catalyzed reactions.