Study on Conditions of Ethanol Fermentation of Mannitol by Pichia angophorae

Ethanol fermentation of different concentration of mannitol by Pichia angophorae was carried out in 250ml Erlenmeyer flasks.The optimum composition of fermentation medium was determined by the tests with concentration of 20g/L,40g/L,60g/L and 80g/L of mannitol.Then an orthogonal test was designed and performed,searching for the best fermentation condition.The results indicated that the optimum medium composition for ethanol fermentation was 20g/L mannitol,0.3g/L yeast extract,0.3g/L malt extract,5g/L(NH4)2SO4,2g/L KH2PO4 and 0.4g/L MgSO4·7H2O.Besides,the optimal fermentation condition was 32℃,150rpm,initial pH value 4.5 and 150ml fermentation liquor with a yield of 0.45 g ethanol(g mannitol)-1.