Research On Hydrolyzing Bagasse Hemicellulose With Enzyme Assisted By Ultrasonic Pretreatment With Acid

This experiment mainly studies the effect of hydrolyzing bagasse hemicellulose with enzyme assisted by ultrasonic pretreatment; In order to recycle xylanase and easy to isolate, we use immobilized technology to fix the enzyme, and deduce Michaelis-Menten Equation about immobilized enzyme; arabinosidase is added in order to improve bagasse hemicellulose enzyme hydrolysis efficiency and speed, and get a simple dynamics model through the modeling. The main research conclusion as follows:(1) This experiment separately inspected the influence of different pretreatment method, ultrasonic temperature, time, ultrasonic power ultrasonic, acid concentration, xylanase content to bagasse. According to single factors of research on ultrasonic pretreatment and optimize process by the response surface method, we acquire optimum conditions:the temperature of the ultrasonic pretreatment is53.07℃, time of the ultrasonic pretreatment is62.2min, the power of the ultrasonic pretreatment is300.71W, sulphuric acid concentration is0.056%.Reducing sugar content is14.421%and increase6.521%in the process. Quadratic model is acquired which regression is significant very much.(2) The experiment study on the xylanase immobilization by glutaraldehyde. The frist, crosslinking, then, immobilizing.Also, This paper probes into the effects of glutaraldehyde concentration, crosslinking time, immobilized time, immobilized temperature, the immobilized enzyme adding amount, and apply the response surface method, choose glutaraldehyde concentration, crosslinking time, immobilized time as significant factors to optimizing the process, we acquire optimum conditions: Glutaraldehyde concentration1.46%, crosslinking time62.2min, immobilized time3.05h. the optimum temperature is50℃, the best pH is5, its thermal stability and pH value is higher than free enzyme, using The immobilized enzyme.Besides, we research on the dynamics of immobilized enzyme, and Km (mg·mL-1) is3.69samller than that of free enzyme,because that molecule of immobilized enzyme is bigger than free enzyme and diffusion resistance of immobilized enzyme increases. Vmax is0.319.(3) The experiment study the effect of Arab glycosidase enzymes to hydrolyzing bagasse hemicellulose with xylanase, Arab glycosidase enzymes have synergistic effect on hydrolyzing and we get the best adding amount of0.1mL. The best pH and temperature of the double enzyme hydrolysis are5.8 and53℃respectively. As long as the substrate enough, reducing sugar yield linear rise approximately.