Preparation Of Immobilized Enzyme By Bamboo Cellulose And Study On Its Properties

Enzymes are protein which have catalytic function in biological cells. Enzymes canpromote all metabolic reactions, no enzymes, metabolism stops, life stops. Enzymes workunder wild conditions, and they have high efficiency and specificity, far better thansynthesis catalysts. Considering stability of enzyme and cost, enzymes were used toimmobilized on carriers in industry. Immobilized enzyme is important in enzymeengineering.China is a large country, covers an area of about9.6million square kilometers.Bamboos can be planted in its most southern territories. Abundant bamboo resources andbamboo fiber are produced in China. Cellulose, which is the most part in bamboo fiber, isnatural polymer material, has a certain spatial structure and flexibility. There are a largenumber of free hydroxyl groups in bamboo cellulose, and—OH could be preparedcellulose derivatives, to combine with amino, mercapto, imidazolyl and indolyl of enzymes.So bamboo celluloses are ideal materials to be carriers of immobilized enzyme.This paper chooses of several common bamboos as raw materials, by smashed,pretreated, and oxidized to oxycellulose of bamboo with sodium periodate-formaldehydemethod, a fine carrier for immobilized enzyme was prepared. Both papain and porcinepancreatic lipase were immobilized by the carrier in this paper, and we considered thefactors which have an effect on the immobilized enzymes, such as characters of carriers,immobilization condition, its microenvironment, stability and so on. At last, an applicationfor hydrolysis of chitosan by immobilized enzymes was preliminary studied.In the experiment of preparation of modified bamboo cellulose carrier materials,through cellulose content measurement, SEM, the specific surface area test and infraredspectroscopy, it can be proved that Bambusa multiplex has the highest content of cellulose.What is more, when placed in5%NaOH solution for1.5h, oxidized in2g/L sodiumperiodate solution for an hour, with the temperature is4℃and pH is5.0, and thencovalented a spacer arm by urea and formaldehyde, the modified bamboo oxycelluloseobtained was a fine carrier for immobilized enzymes.The papain was immobilized by the carrier in this paper, and the results show that themodified bamboo oxycellulose was a fine carrier for immobilized papain when it wasimmobilized for24hours with the temperature is4℃and pH is7.5. Under the conditionsof50℃and pH7.5, it had the best catalytic activity for hydrolysis of casein, the best one could be805.5U/g.What’s more, it is better than free enzyme for its thermal stability andalkali resistence, and it could remain76.9%after it was used repeatedly for6times.The porcine pancreatic lipase, PPL for short, was immobilized by the carrier in thispaper, and the results show that the modified bamboo oxycellulose was a fine carrier forimmobilized PPL when it was immobilized for24hours with the temperature is4℃and pHis7. However,1.5mL tween-80was necessary as surfactant in experiments. Under theconditions of55℃and pH7, it had the best catalytic activity for hydrolysis of olive oilemulsion, the best one could be166.7U/g.What’s more, it is better than free enzyme for itsthermal stability, and it could remain74.6%after it was used repeatedly for6times.Experimental studies have shown that, immobilized papain and immobilized PPL, asnon-specific hydrolases, could hydrolyze chitosan efficiently under the conditions of roomtemperature and low value of pH. This is one of the applications of two immobilizedenzyme products in chemical industry. In the paper, immobilized enzymes hydrolyzedchitosan more slowly than free enzymes, but more stably. The process could be madecontinuous, and the yields of reaction products, which were reducing sugars, were equal tothose catalysed by free enzymes.