Effect of phosphoric acid pretreatment on enzymatic hydrolysis of microcrystalline cellulose.

Autor: Zhang J; State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510641, China., Zhang B, Zhang J, Lin L, Liu S, Ouyang P
Jazyk: angličtina
Zdroj: Biotechnology advances [Biotechnol Adv] 2010 Sep-Oct; Vol. 28 (5), pp. 613-9. Date of Electronic Publication: 2010 May 15.
DOI: 10.1016/j.biotechadv.2010.05.010
Abstrakt: Microcrystalline cellulose (MCC) was pretreated with phosphoric acid at 323K for 10h. 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, 0.218min(-1), respectively at 278K, 293K and 308K. The activation energies of MCC and P-MCC hydrolysis reactions were found to be 22.257 and 19.721kJ mol(-1). The major hydrolysis products of MCC and P-MCC were cellobiose and glucose. Hydrolysis of MCC for 120h 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.
(Copyright 2010 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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