Gibberella intermedia WX12产特异性糖苷酶的发酵工艺优化

赤霉菌（Gibberella intermedia WX12）糖苷酶能将黄姜薯蓣皂苷转化为薯蓣皂苷元。先后采用单因素实验和正交实验对G. intermedia WX12发酵产糖苷酶的培养基组分和发酵工艺进行了优化。确定最佳发酵工艺条件为：葡萄糖5 g/L，酵母粉25 g/L，NaCl 1.16 g/L，KH2PO4 2.72 g/L，MgSO2 0.3 g/L，培养基初始pH 6.0，接种量为体积分数8%。G. intermedia WX12在上述条件下，于220 r/min、30 ℃摇床培养96 h，糖苷酶活性达到28.1 U/mL，较优化前提高4倍。在此基础上利用粗酶液对黄姜薯蓣皂苷进行转化，50 ℃条件下转化12 h后，薯蓣皂苷元转化率可达到60%。
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