Preparation Of Bagasse Fiber-immobilized Enzyme And Preliminary Study On The Treatment Of Sugarcane Juice

It's the key technology during the process of producing sugar to remove non-sucrose in the process of clarifying.At present,the method of clarifying for most sugarcane plants in China is sulfuric acid method,which has several disadvantages including high content of calcium salt and high energy consumption.Therefore,there are some researchers at home and abroad who used enzymes to remove non-sucrose from sugarcane juice,and the effect is significant in energy consumption reduction and lessening production cost.However,there are some shortcomings in free enzyme treatment,such as poor stability,easy inactivation,difficulty in product separation and purification,and high cost of products,which is in urgent need of improvement.The bagasse is a by-product of the sugar plant,which has large volumes of cellulose and is not soluble in water.Cellulose contains a large amount of free hydroxyl,and its derivatives can be combined with enzyme protein molecules to prepare the immobilized enzyme.In this paper,the immobilization of free enzyme was carried out to prepare bagasse fiber-immobilized enzyme,which was used to treat sugar cane mixture juice,so as to reduce the cost of free enzyme and to facilitate the continuous production.The carrier of immobilized enzyme of bagasse fiber was modified by oxidation method.Two methods,adsorption and covalent binding,were used to immobilize high temperature alpha-amylase and pectin lyase respectively.The optimum process conditions of carrier preparation and immobilized enzyme were researched.And the immobilized high temperature alpha-amylase and immobilized pectin lyase were used to purify the mixed juice of sugarcane.The main research content and results are as follows:(1)The effects of various reaction factors on the preparation of modified bagasse fiber carrier were studied,and the preparation conditions were optimized.Under the optimized conditions,the content of aldehyde was 7.589mmol·g-1.The properties and structure of the obtained dialdehyde cellulose were characterized by scanning electron microscopy(SEM)and Fourier transform infrared(FTIR).The results showed that the bagasse was modified in good condition.(2)The high temperature alpha-amylase was immobilized on the carrier of modified bagasse fiber and the immobilization conditions were studied.The results showed that compared with free enzyme,the stability of immobilized high temperature alpha-amylase was good.The heat resistance and alkali resistance of high temperature alpha-amylase were enhanced,it has good catalytic activity.The reusability of the high temperature alpha-amylase hydrolyzed starch was studied.The results showed that the enzyme activity could reach the initial activity of 76.51%after repeated use of 6 times,the stability of the enzyme was good.After 7 days of preservation,the enzyme activity was still 86.75%of the original enzyme,and the allosteric enzyme liquid was completely inactive,which improved the enzyme storage stability.(3)The pectin lyase was immobilized on the carrier of modified bagasse fiber and the immobilization conditions were studied.The results showed that compared with free enzyme,the stability of immobilized pectin lyase was good.The heat resistance and alkali resistance of high temperature alpha-amylase were enhanced,it has good catalyticThe reusability of the pectin lyase hydrolyzed pectin was studied.The results showed that the enzyme activity could reach the initial activity of 66.72%after repeated use of 6 times,the stability of the enzyme was good.After 7 days of preservation,the enzyme activity was still 86.41%of the original enzyme,and the allosteric enzyme liquid was completely inactive,which improved the storage stability of pectin lyase.(4)Two kinds of immobilized enzymes were used to treat sugarcane mixed juice and compared with the treatment effect of free enzyme.The results showed that the treatment of mixed juice with immobilized enzyme had little change in the brix and purity of sugarcane juice,and under the moderate conditions to achieve a better clarification effect.The color value reduction was greater than the degree of free enzyme as well.