Study On Preparation Of The Charged Ultrafiltration Membrane And Separation Of Yeast Extract

Yeast Extract, which was a nutritional natural condiment, consisted of 10% trehaloseand a lot of proteins which badly disturbed the extraction of trehalose, so a method wasdescribed according to the paper where the procedure based on the charged membrane byself-made, the results were as fellows:1. It was obtained that the minimal protein was 1.5mg/mL by means of the biuretreaction through the study of assay method. We also found the polarimetry is suitable fortrehalose's analysis, and the linear relationship between the concentration and the opticalvalue was in the range 0.1~50mg/mL, the results showed that the method is simple, fastand accurate.2. According to the paper, the hydrophilic sulfonic acid group was introduced topolysulfone——a kind of membrane material made by heterogeneous sulfonationreaction, then a charged membrane with fine material was prepared by phase inversionmethod. The charged membrane had both good separation character and the high flux,and also good anti-fouling ability. The process of membrane preparation and membraneseparation performance were studied in the paper, the results showed the relation of them.3.Based on the investigation of ultrafiltration process, it was obtained that operationalpressure, temperature and the concentration of solution were important elements whichinfluenced membrane flux and rejection rate. A series of orthogonal experiments werecarried out to optimize the parameters, whereafter, to make general evaluate to them. Amass transferring equation was educed : J=0.9624ln(36.223/Cb), which showed a linearrelationship between flux and logarithm of solute concentration. Moreover, we also foundthat the various cleanout reagent had various effect on the charged membrane fouling. Toprotein enzyme, the flux recovery coefficient reached 0.95. Compared to original, themembrane flux declined only 60% after running for 50h.4. Based on the scale-up study, the overall recovery was found to increase with theincrease of diafiltration solvent. Furthermore, the yield value of trehalose was 95% whendiafiltration solvent reach 200%(relative to the volume of concentrated solution).Ultrafiltration and continuous diafiltration treatment using the charged membrane, gavethe final rejection rate of 90% for protein, the permeation rate of 95% for trehalose, thepurification degree of 50% for trehalose.