Application Of Chitosan Beads Immobilized Pectinase In The Treatment Of Whitewater Anionic Trash

In this dissertation, the immobilization of alkaline pectinase on modified chitosan beads and its application in the treatment of anionic trash in whitewater were explored for the first time. The cross-linking reaction of glutaraldehyde and chitosan and immobilized methods were discussed. Also, the immobilized enzyme was characterised and a new enzymatic route for treatment of white water was developedResults showed that cross-linking reaction of glutaraldehyde and chitosan beads was well according with the pseudo-second-order equation and Freundlich equations. After the treatment of polygalacturonic acid by modified and unmodified chitosan beads, it seems that inner diffusion is not the only process control on the adsorption of polygalacturonic acid. And it just has influence on the adsorption process.With the increase of pH value of polygalacturonic acid solution, the adsorbance of chitosan beads and its derivative with poly-galacturonic acid fistly gradually decreased, but then increased. In addition, increasing sodium chloride concentration obviously decreased the absorbance of chitosan beads and its derivative on poly-galacturonic acid.The immobilization conditions of pectinase on chitosan beads were optimized and dual system (first glutaraldehyde then EDC) immobilized alkaline pectinase showed the highest activity. The optimum dosages of glutaraldehyde and EDC were of 0.005% and 1%, respectively. Immobilized enzyme optimal pH is 8.5, optimum temperature is 55℃. Immobilized enzyme has better temperature stability,pH stability,storage stability and operation stability.Compare the IR and SEM analysis of two chitosan beads, we can find the modified chitosan beads (by glutaraldehyde and EDC) is very helpful to enzyme immobilization. It proves that first glutaraldehyde then EDC immobilized enzyme method is really effective.When we use immobilized enzyme to treat PGA, with the bead dosage and treatment time change the PGA cation demand value have different degrees decline. From the comparation of blank chitosan beads,free enzyme,immobilized enzyme treatment of whitewater, it concludes that immobilized enzyme treatment effect is best, because it have both adsorption property of blank chitosan and degradation of free enzyme. In the immobilized enzyme treatment process of whitewater, after immobilized enzyme recycle six times, whitewater CD reduce 36.6%, after 10 times, CD reduce 27.5%, achieve good recycle performance, lay a good foundation for production. Through the GPC analysis of PGA molecula weight by immobilized enzyme treatment in different dosage and time, the immobilized enzyme treatment effect is significantly. After treatment by 2g immobilized enzyme 15min, the PGA Mw decreased from 4.815×104 to 6.790×103, it proves again immobilized enzyme has good treatment effect.