Production of alginate beads by emulsification/internal gelation. I. Methodology

Small diameter alginate beads (microspheres) were formed via internal gelation of alginate solution emulsified within vegetable oil. Gelation was initiated by addition of an oil-soluble acid thereby reducing the pH of the alginate solution and releasing soluble Ca2+ from the citrate complex. Smooth, spherical, micron-sized beads were formed. The mean diameter ranged from 200 to 1000 microns, controlled by the reactor impeller design and rotational speed. The technique has potential for large-scale and continuous applications in immobilization.