Agar powder, also known as agar-agar, is a plant-based gelatinous substance derived from red algae (primarily species of Gelidium and Gracilaria). It is commonly used as a vegetarian and vegan alternative to gelatin in cooking, baking, and scientific applications.Solid culture medium prepared with AGAR can be used for high-temperature culture without melting, and when inoculated before solidification, it will not scald the culture to death. Therefore, AGAR is the most widely used coagulant in the preparation of various biological culture media.