Optimization Of Polysaccharide Of Pullulan Fermentation Process And Pilot Production

Pullulan is a biological macromolecule material produced by Aureobasidium pullulans.Potential applications of pullulan and its derivatives have been of interest in past few years in a broad range of industrial fields including the food,cosmetics.In this paper,the fermentation process of pullulan polysaccharides and pilot production was studied,the main research contents and results were as follows:1.Building a set of method to detect pullulan molecular weight by high performance liquid:0.05 M NaSO4 as Mobile phase,sample quantity:20 uL,flow rate:0.5 mL/min,column temperature:25?,detector temperature:30?.2.The seed culture medium and culture conditions were optimized,the optimizest medium components:Sugar 80 g/L,Yeast powder leaching 4.28 g/L,(NH4)2SO4 1 g/L,K2HPO4 2.78 g/L,MgSO4·7H20 0.8 g/L,NaCl 2.5 g/L,FeSO4·7H2O 0.03 g/L,the optimizest culture conditions:Initial pH 6.5,32?,190 r/min.3.Higher temperature(32?)and stirring speed(500 r/min)supported cell growth,Lower temperature(28?)and stirring speed(400 r/min)stimulate pullulan synthesis.When pH was controlled at 5.0 after stationary phase,the pullulan production could be increased again.The optimizest fermentation conditions were:Initial pH 6.0,wind was always 4 L/min;Before stationary phase,Stirring speed was 500 r/min,the temperature was 32?,and pH wasn't controlled.Subsequently,the stirring speed and temperature were adiusted to 400 r/min and 28?.And the pH was controlled at 5.0.4.As for cell morphology,temperature within a certain range was almost no influence,pH largely influenced.And the morphology of A.pullulans was slightly different under the condition of different ventilation and stirring.Under higher ventilation,A.pullulans begined to synthetic melanin.5.Molecular weight of pullulan changed as the fermentation time changes.The pH had significant effects on the molecular weight.The higher molecular weight of pullulan was obtained at lower pH.6.According to the experience,5 m3 pilot experiments had been carried out.The products were all meeting the national standards and got the license for the manufacturing of pullulan polysaccharides in early 2014.