An effective and simplified scale-up strategy for acarbose fermentation based on the carbon source control.

The scale-up strategy for acarbose fermentation by Actinoplanes sp. A56 was explored in this paper. The results obtained in shake-flask cultivation demonstrated that the ratio of maltose and glucose had significant effects on the biosynthesis of acarbose, and the feeding medium containing 3:1 (mass ratio) of maltose and glucose was favorable for acarbose production. Then the correlation of the carbon source concentration with acarbose production was further investigated in 100-l fermenter, and the results showed that 7.5-8.0 g of total sugar/100 ml and 4.0-4.5 g of reducing sugar/100 ml were optimal for acarbose production. Based on the results in 100-l fermenter, an effective and simplified scale-up strategy was successfully established for acarbose fermentation in a 30-m(3) fermenter, by using total sugar and reducing sugar as the scale-up parameter. As a result, 4,327 mg of acarbose/l was obtained at 168 h of fermentation.