A Study On Decolorization And Extraction Techniques Of Pullulan5L Expanded Fermentation

The present study, with mutational budding aureobasidium pullulans D1-11as theoriginal strain, which prepared fermented liquid of pullulan for larger scale production of5L fermentation on the basis of100mL fermentor, investigated to what extent inoculationand rotational speed may influence the expanded fermentation. Differences between the100ml fermentor and the expanded fermentation in biomass, production of polysaccharid,protein and pigment were addressed. Besides, the appropriate method of decolorizationwas suggested through a comparative study on the devices of powdered active carbon,diatomite, organic solvent and H2O2. The optimal technical parameters were determined byresponse surface methodology (RSM). Moreover, the extraction methods ofenzyme-NaC1-alcohol, microwave–alkali water and ultrasonic-saline were analyzed fromthe aspects of univariate index and response surface methodology with statistical resultsidentifying the most appropriate extraction technology. The main findings of this study areas follows:(1) The optimum conditions of expanded fermentation for pullulan under whichthe content of the polysaccharide reaches3.66g/L are: volume3.5L, temperature40℃,time5d.(2) The maximum decolorization rates of diatomite, organic solvent and H2O2methods are87.43%,69.22%and80.61%respectively, with attrition rates of saccharide of13.94%,18.46%and18.24%in accordance. As regards the results from RSM, the poweredactive carbon device, with its advantages of simplicity, effectiveness, low-cost andadaption to large scale industrial production, among the four decolorization methods,reached the optimal rate of88.58%with13.59%attrition in saccharide under the technicalparameters as follows: pH6.3, time42min, temperature48℃and enzyme added1%.(3)The method of ultrasonic-saline reached the highest extraction rate of79.43%. Othersranking from high to low are microwave-alkali water approach (78.66%) andenzyme-NaC1-alcohol device (64.16%). Taking the technical parameters into consideration,the microwave-alkali water method, with its optimum conditions of concentration0.5mol/L, microwave power P40,temperature70℃and time90s, was selected as theoptimal technique.