Composites of lignin and biologically active materials

The subject invention is directed to composites of lignin and biologically active materials. The composites consist of a biologically active agent dispersed throughout an alkali lignin material in a ratio of .1:1 to 1:10 of the biologically active agent to alkali lignin. The biologically active agent is either entrapped by the lignin macromolecular matrix or held by physical-chemical forces of van der Waal's, hydrogen bonding or ion association types. The active agent is slowly released on application either by diffusion through the lignin solid, or through degradation or dissolution of the lignin. The composites are obtained by a variety of processes including the coprecipitation-inclusion from an aqueous alkaline lignin solution by adding acid or salts, the drying of a precipitated lignin slurry biologically active agent dispersion, or the eliminaton of a common solvent from a lignin-biologically active organic agent mixture. The biologically active agent may be incorporated in the lignin matrix at dimensions varying from molecular size to droplet or particle sizes.