Agar powder is a polysaccharide derived from seaweed and used as a solidifying agent in microbiological culture media. It is used to create a solid surface for growing bacteria, fungi, and other microorganisms., Agar powder is typically mixed with nutrients and water and then autoclaved to sterilize the mixture. The mixture is then poured into petri dishes or other containers and allowed to solidify. This is supplied by Thermoscientific.