An optimized industrial fermentation processes for acarbose production by Actinoplanes sp.  A56. 
Acarbose, a competitive α-glucosidase inhibitor, is clinically and widely used in the treatment of type II diabetes mellitus.  In order to improve the industrial acarbose productivity by Actinoplanes sp.  A56, the classical fermentation conditions such as total sugar concentration in broths, pH value and dissolved oxygen (DO) level were systematically investigated in a 30000-l fermenter, respectively.  It was observed that a high-concentration total sugar (75-80 g/l), 7.0-7.2 of pH value and 40-50% of DO concentration were favorable for acarbose production.  As a result, the final acarbose yield was elevated to approximately 5000 mg/l at 168 h of fermentation.