| abstract |
Biological materials such as enzymes, proteins and peptides are encapsulated by forming a mixture of the material and an aqueous non-ionic polymer solution, spraying the mixture into a circulating water-immiscible nonsolvent for the polymer at a temperature sufficient to freeze the beads and drying the frozen beads to remove essentially all unbound water such as to provide a water content of about 1-2 weight percent. Suitable non-ionic polymers are poly(vinyl alcohol), polyvinylpyrollidone, dextran and derivatized cellulose. A densification agent such as alumina may be present in the polymer solution to enhance specific gravity of the beads formed. Encapsulated material such as microbes produced by this process provide useful agricultural agents which can be delivered to the market in a dormant state and suitable for delivery to soil or plant leaves. The beads can be applied dry, via a planting or an insecticide box, or wet via a spray nozzle. |