Study on Production of Functional Oligosaccharides by Enzymatic Hydrolysis in Cornhusk
|Keywords||Corn bran Cellulase Xylanase Hydrolysis Adsorption mechanism Cellooligosaccharide XOS|
Corn bran fiber residues of starch production, large and concentrated. The topics to corn bran as raw material, the use of cellulase and xylanase hydrolysis of oligosaccharides and oligosaccharide production of fibers, the research work in this area not only has the important academic significance, but also has important economic and social value . At 40 ℃, solid-liquid ratio 1:10, NaOH concentration of 2% under the conditions for 24h on pretreated corn bran hemicellulose extraction was 85%. This method is mild operating conditions, low energy consumption, cellulose and hemicellulose without damaging for further enzymatic oligosaccharide prepared to lay a good foundation. Xylanase enzyme on the nature and process of xylan hydrolysis reaction was studied on the basis of the enzyme Preparation XOS process was optimized at 50 ℃, pH4. 8, wood xylanase dosage 50IU / g substrate, substrate concentration of 3.0% under the conditions of reaction time 2h Xylo average degree of polymerization of 2.26. Foreign-cut for cellulase-β-glucanase (C1), endo-type-β-glucanase (CMC) and cellobiase (CB) in corn bran fiber adsorption characteristics of substrates have conducted intensive studies and found that in certain enzymatic conditions (substrate concentration 5%, pH 4. 8,50 ℃), C1, CMC mainly adsorbed on the fibrous substrate, whereas most of the free CB is in the liquid phase . The results for deep understanding of the catalytic mechanism of cellulase to optimize the hydrolysis reaction of cellulose, etc. is important. Removed during the hydrolysis enzymes cellobiose, cellooligosaccharide help increase the proportion of the product and the average degree of polymerization. At 50 ℃, pH4. 8, the substrate concentration of 5%, enzyme dosage 7FPIU / g substrate, the reaction 6h, cellooligosaccharide conversion rate of 77%, average degree of polymerization of 3.44. Further extension of the reaction time, reaction of glucose in solution will increase cellooligosaccharide conversion rate. Cellulase adsorption properties using established feeding batch hydrolysis process: when the first enzymatic reaction after 6h, filtered to remove the filtrate, make the same amount of fresh substrate, the reaction was continued for 10h. This process is not only beneficial to remove Cellobiase, while the C1 and CMC components to achieve recycling reuse. The test results show that: 100kg corn bran can be obtained 15. 2kg cellooligosaccharide products and 21. 1kg XOS products, raw materials conversion was 32.7%, showing good economic benefits.