Optimization of Culture Conditions for Specific Production of Glycosidase from Gibberella intermedia WX12

Abstract:

A glycosidase from Gibberella intermedia WX12 could convert dioscin into diosgenin. Through the single factor and orthogonal experiments，the optimal fermentation medium was found to consist of 5 g/L glucose，25 g/L yeast，1.16 g/L NaCl，2.72 g/L KH2PO4 and 0.3 g/L MgSO4 and the culture parameters for dioscin-glycosidase production were temperature 30 ℃，rotation speed 220 r/min，initial pH 6.0 and inoculum size 8.0%（v/v）. With these conditions，the enzyme production had a similar trend to that of cell growth curve，and the highest activity of glycosidase reached 28.1 U/mL after fermentation for 96 h，which was 5 times higher than that before optimization. A conversion rate of 60% was achieved when the obtained crude enzyme was used to convert dioscin from Dioscorea zingiberensis C.H. Wright into diosgenin at 50 ℃ for 12 h.