PROBLEM TO BE SOLVED: To produce the subject body capable of efficiently adsorbing an active ingredient by forming the adsorptive body/gradually releasing body having a function adsorbing the active ingredient such as all kinds of chemicals and the function gradually releasing the adsorbed active ingredient from a biopolymer and using a silk protein or an animal-originated keratin, collage, etc., as the biopolymer.
SOLUTION: The adsorptive body/gradually releasing body is formed by using the biopolymer having the adsorbing function adsorbing the active ingredient, for example, enzyme, toxin, antibiotic, drug, vaccine, agrochemical, perfume, etc., and the gradually releasing function gradually releasing the adsorbed active ingredient from a biopolymer. The silk protein or the animal-originated keratin, collagen and gelatin are used as the biopolymer. Alternatively, silk fibroin or wool keratin is used as the biopolymer, and the silk fibroin or the wool keratin having ≥7% crystallinity based on X-ray diffraction strength analysis is used. A reduced keratin or S-(substd.)alkylkeratin having a SH group can be used.