The most widely used organisms are fungi, and several enzymes and organic acids are synthesized by species of Aspergillus. Over the past 1,000 years, the use of hydrolytic enzymes from fungi has become more prevalent in Japanese fermentation industries. The molds Aspergillus oryzae, A. sojae, A. awamori and A. saitoi are of great practical importance in fermentation industries, enzyme technologies and food industries in Japan. This book discusses the catalytic and molecular properties of unique and characteristic enzymes obtained from Aspergillus fungi used in Japanese bioindustries.