Effect of phosphoric acid pretreatment on enzymatic hydrolysis of microcrystalline cellulose
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- 作者：Juanhua Zhang ; Beixiao Zhang ; Jingqiang Zhang ; Lu Lin ; Shijie Liu ; Pingkai Ouyang
- 关键词：Cellulose ; Phosphoric acid ; Decrystallization ; Kinetics ; Sugar
- 刊名：Biotechnology Advances
- 出版年：2010
- 出版时间：September-October 2010
- 年：2010
- 卷：28
- 期：5
- 页码：613-619
- 全文大小：950 K
文摘
Microcrystalline cellulose (MCC) was pretreated with phosphoric acid at 323 K for 10 h. X-ray diffraction (XRD) and Atomic Force Microscope (AFM) analyses revealed that the fiber surface morphology of pretreated MCC (P-MCC) were uneven and rough with the crystalline diffraction peaks of P-MCC decreased to a distinct range. The X-ray Photoelectron Spectroscopy (XPS) analysis showed that the uneven and rough surface of P-MCC could enhance the adsorption of cellulose to the molecular surface of cellulose, which is one of the key factors affecting enzymatic hydrolysis of cellulose. A reversible first order kinetics was employed to describe the adsorption kinetics of cellulase to MCC and P-MCC, and the adsorption rate constants of MCC and P-MCC were found to be 0.016, 0.024, 0.041, and 0.095, 0.149, 0.218 min− 1, respectively at 278 K, 293 K and 308 K. The activation energies of MCC and P-MCC hydrolysis reactions were found to be 22.257 and 19.721 kJ mol− 1. The major hydrolysis products of MCC and P-MCC were cellobiose and glucose. Hydrolysis of MCC for 120 h resulted in yields of glucose (7.21 % ), cellobiose (13.16 % ) and total sugars (20.37 % ). However, after the pretreatment with phosphoric acid, the corresponding sugar yields resulted from enzymatic hydrolysis of P-MCC were increased to 24.10 % , 41.42 % , and 65.52 % ; respectively, which were 3.34, 3.15, and 3.22 times of the sugars yields from enzymatic hydrolysis of MCC.