摘要
Abstract
Optimization of medium composition and submerged culture conditions for β-glucosidase and intracellular polysaccharide (IPS) production by Grifolafrondosa was studied.Glucose and bran were the most suitable carbon and nitrogen sources determined by single factor experiment.Afterwards,response surface methodology was used to achieve the favorable medium composition,and a quadratic regression equation for the change of enzyme activity and IPS with glu cose and bran was established.The result was glucose 27.83 g/L,bran 35.57 g/L,KH2PO4 3 g/L,MgSO4 1.5 g/L,VB1 0.05 g/L while biomass,IPS and β-glucosidase can be obtained respectively at 1.397 g/100 mL,2.176 g/L,22.177 U/100 mL,which is 1.9,0.75,2.71 timesas much before optimization.The effect of submerged culture conditions including pH,inoculation,temperature and fermentative time on enzyme activity and IPS was investigated subsequently.The result shows the optimal pH and inoculation for both β-glucosidase and IPS production in shake flask cultures were 5 and 10％.In addition,the submerged culture of Grifolafrondosa can be finished at 7 dayswhen choose the liquid seed cultured for 7 days and the temperature and rotation speed were set at 25 ℃ and 180 r/min,respectively.关键词
灰树花/液体发酵/β-葡萄糖苷酶/胞内多糖/响应面/发酵条件Key words
Grifolafrondosa/submerged culture/β-glucosidase/intracellular polysaccharide/response surface methodology/submerged culture conditions
