Preparation of Lipase-Electrospun SiO Nanofiber Membrane Bioreactors and Their Targeted Catalytic Ability at the Macroscopic Oil-Water Interface.

Lipase is one of the most widely used enzymes in biocatalysis. Because of the special structure of the catalytic active center, lipases show high catalytic activity at oil-water interfaces. Hence, the interface plays a key role in activating and modulating lipase biocatalysis. Compared with traditional catalytic systems that offer interfaces, such as emulsions, a lipase-membrane bioreactor exhibits many obvious advantages when at the macroscopic oil-water system. In our current research, a series of new lipase (BCL)-SiO nanofiber membrane (NFM) bioreactors prepared via combined electrospinning and immobilization strategies were reported. These SiO NFMs assisted BCL in reaching the oil-water interface for efficient catalysis. The enzyme loading capacity and catalytic efficiency of BCL-SiO NFMs varied with the surface hydrophobicity of the electrospun NFMs. As the hydrophobicity increased, the activity decreased from 2.43-fold to 0.74-fold that of free BCL. However, the lipase-loading capacity increased obviously when the hydrophobicity of the SiO NFMs increased from 0 to 143°, and no significant change was observed when the hydrophobicity of the SiO NFMs increased from 143 to 153°. The gel trapping technique proved that the hydrolytic activity of the different BCL-SiO NFM bioreactors depends on the contact area of the membrane at the oil-water interface. BCL-SiO NFM, BCL-SiO NFM-C, and BCL-SiO NFM-C retained 32, 83, and 42% of activity, respectively, after five cycles of reuse. The current work was a useful exploration of the construction and modification of lipase-membrane reactors based on electrospun inorganic silicon.