The Study On Technology Of Pullulan Segregation And Purification

Pullulan, an extracelluar polysaccharide is obtained by fermentation using fungs, Aureobasidiumpullulan. It is transparent, colourless, tasteless, odourless, tenacious, resistant to oil and grease andunaffentde by small thermal variations. So it can apply in many territory, such as, medicine, food,cosmetics, nicotiana tabacum, agriculture. It is multifunction material of having the largest economic valueand exploitation potentiality.Aureobasidium pullulan produce dark gress to black pigment which unfavourably apply in confinementterritory, it may solve this problem from two aspects. On the one hand, it can obtain mutant strain whichproduce more pullulan and less pigment by ultraviolet mutagenesis, chemistry mutagenesis and molecularbiology. On the other hand, removing pigmeng and impurity by downstream technology. In this articles, thesystematic studies related to different extraction methods, purification using pullulan fermentation.The paper decolorize by using granulo-activated carbon, powder-activated carbon, diatomaceous earth. Itinvestgated decolorization result from dosage, temperature, decolorization time, pH, concentration ofsolution, decolorization frequency Determining the best decolorization condition. Contrastingdecolorization result, the studies showed that decolorization result of powder-activated carbon was the best.The optimum conditions obtained by experiments were as follows: dosage of powder-activated carbon was0.6%, temperature, 40℃, time 20min, pH (3-6), frequency two times, concentration of solution(diluting 3times by adding water). Decolorization ratio was 93.45%. Saccharide loss was 9.36%.Various extraction methods of organic solvent were studied comparatively, the results showed thatmethods of mixture methyl ethyl ketone and alcohol was better than other extraction methods. The ratioof methyl ethyl ketone and alcohol was 40/60.Four methods (sevage method, TCA method, NaCI method and CaCl₂ method) to de-protein from crudepullulan were studied, the results showed that TCA method was more effective.Contrasting two methods (D101 resin and membrane filtration) to de-ion, the results showed that thelater was more effective, ratio of de-ion was 92.5%.Contrasting four kinds resin (D201, D4006, AB-8, and D3500) to decolorization, the results showed thatthe former was more effective.In the studies that DEAE-cellulose segregated and purified puUulan, elution velocity was 2ml/min.Eluant was distilled water and Nacl solution (0.05mol/l, 0.1mol/l), purified pullulan was identified withSepharose CL-6B.