Fabricating biopolymer-inorganic hybrid microspheres for enzyme immobilization: Connect membrane emulsification with biomimetic mineralization

Abstract The organic-inorganic hybrid composites displayed great potential for biotechnological and biomedical application. In this research, a gelatin/alginate/silica hybrid microsphere was developed by a synergy of membrane emulsification process and biomimetic mineralization method. The gelatin was mixed and complexed with alginate solutions (water phase). The water phase was extruded through a Shirasu Porous Glass (SPG) membrane, and then was crosslinked, which formed gelatin/alginate microspheres. The biomimetic mineralization was occurred in situ by immersing gelatin/alginate complex in a Na2SiO3 solution, while silica was formed around the organic microspheres, resulting in the final gelatin/alginate/silica hybrid microspheres. These microspheres were characterized by SEM, TEM, EDS, TGA/DTA, and DSC. The hybrid microcapsules present a more than 40% mass fraction of the inorganic component, and displayed superior swelling resistance to biopolymer complex microspheres. Glycerol dehydrogenase (GlyDH) was immobilized in the obtained novel gelatin/alginate-silica hybrid microspheres as the model enzyme. Due to the protective effect of carriers, the pH tolerance stability, storage and recycling stability of the immobilized GlyDH were all improved in comparison with free GlyDH.