Agar, a jelly like substance is a complex polysaccharide which is extracted in water from certain species of red algae, e.g., Gelidium, Gracillaria etc. This is produced and stored in their cell walls along cellulose and contains galactose and sulphate. It is used as a base in culture media for algae, fungi, bacteria, etc. and also as emulsifier in food, cosmetics, leather and pharmaceutical industries.