Preparation And Protection Mechanism Of Trehalose

In this thesis, the determination of trehalose, its culture strain selection, fermentation conditions, trehalose extraction, optimal control of the fermentation and mechanism of protection were studied.The method to analyze trehalose content in biological materials by trehalase was set up. The best analytical conditions were: pH5.6 , 50℃,20min.A mutant with better property was selected from mutagenized Filobasidiun capsuligenum AS.1565 strain. In flask culture, its dry cell weight could be 17.83 mg/ml, meanwhile trehalose content was 3.94 mg/ml, extracellular polysaccharide content was 0.12 mg/ml.The composition of optimal flask culture medium was: glucose 8.0%, corn steep liquor 0.8%, validamycin A 0.5μ g/ml, KH₂PO₄ 0.2%, MgSO₄ ? 7H₂O 0.085%, NH₄SO₄ 0.1%, MnSO₄ ? 7H₂O 0.04%, silicone oil 0.01%. The optimal fermentation conditions were: 30℃, pH6.0, 180rpm stirring , 50ml culture volume , strain age 30h , 5% inoculation volume.On the basis of flask culture, the fermentation was enlarged to 5L jar, after 48h culture, the dry cell weight was 29.7 mg/ml, trehalose content was 6.3 mg/ml, 66.57% and 59.50% higher respectively than unoptimized fermentation.The kinetic model of the fermentation was established by analyzing batch culture process, The equation was:dX/dt=μ_mX(1 - X/X_m)dP/dt=V_mSX/(K_m+ S) - adX/dt- dS/dt=1/Y_p/s ? dP/dt + 1/Y_x/s ? dX/dt + mXThe best technological conditions to extract trehalose were as follows. The cell was dried under 105 °C for 5h, then trehalose was extracted with 50%ethanol-water solution for 1.5h, and purified by ion exchange chromatography...