Research On The Production Of Pullulan Produced By Aureobasidium Pullulans

Polysaccharide of pullulan is a biological macromolecule material produced by Aureobasidium pullulans.At present,Japan had monopolied the market,which limited the application of pullulan.So the pullulan fermentation process optimization to reduce the production cost and at the same time,the control of molecular weight is of great significance.The paper explores effect of temperature,pH,dissolved oxygen on Aureobasidium pullulans,particularly on cell growth,pullulan yield,fermentation substrate,polysaccharide,molecular weight and other parameters.When the temperature is at 32 ?,more suitable for Aureobasidium pullulans growth,when the incubation temperature at 28 ?,pullulan production reached the maximum yield,We finally put forward two stage temperature control culture method,which pullulan yield increased to 74.83 g/L;Through the single factor experiments researched the effect of the pH on pullulan fermentation,results show that the nature pH 6.5 was Aureobasidium pullulans optimum growth pH;constant pH 5.5,pullulan production reached peak.At the Ventilation of 4 L/min,speed of 400 r/min,the cell growth rate is the fastest.Through the single factor experiments to explore the effect of growth factor and surface active agent on Aureobasidium pullulans fermentation.The experimental results show that 0.2 g/L serine and 0.04 g/L threonine fermentation of Aureobasidium pullulans had a more significant impact.Cationic CTAB,anionic SDS did not favor the growth of bacteria,and 1 g/L tween 40 couble be significantly promoted the pullulan synthesis,pullulan final yield is 85.39 g/L.Through the Aureobasidium pullulans were observed,when the mycelial morphology is swollen conidia and chlamydospores,synthesis of pullulan has obviously promoted role.According to the existing experimental results,we conducted 9 batches of 5000 L fermentation test of Aureobasidium pullulans,we solved the problems encountered in the actual production process,and each batch of products are in line with national standards,so the subject of industrialized production of pullulan polysaccharide had certain guiding significance.