Characteristics of Acid-Stable α-Amylase Production by Submerged Culture of Aspergillus kawachii

Abstract A culture medium having a suitable composition for acid-stable α-amylase (asAA) production by submerged culture of Aspergillus kawachii IFO4308 ( shochu white- koji mold) is described. Using the proposed submerged medium, approximately 130 mg of asAA protein per liter of the medium were produced at 30°C for 5 d cultivation. The mold had glycogen as the storage polysaccharide and when the content of storage glycogen (CSG) began to decrease in the presence of an inducer such as dextrin, the production of asAA always began. A high level of asAA was produced after production began and when CSG decreased virtually to zero, however, when CSG started to increase, as AA production tended to be repressed. CSG was affected by both the glucose concentration of the medium and the growth rate of the mycelia. The amount of asAA produced was approximately proportional to the amount of mycelia which had grown after asAA production began.