Aureobasidium pullulans popularly known as Black Yeast is a micro-fungus that occurs frequently in a wide range of habitats. Earlier it was known as Pullularia pullulans. Aureobasidium pullulans produces a wide range of useful products including a polysaccharide Pullulan. Pullulan is a linear chain of glucose units. It posses several potential application in various fields. This book will throws light on production of this polysaccharide at laboratory level.