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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Effect of cellulose physical characteristics, especially the water sorption value, on the efficiency of its hydrolysis catalyzed by free or immobilized cellulase

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Author(s):
Ogeda, Thais L. [1] ; Silva, Igor B. [1] ; Fidale, Ludmila C. [1] ; El Seoud, Omar A. [1] ; Petri, Denise F. S. [1]
Total Authors: 5
Affiliation:
[1] Univ Sao Paulo, Inst Quim, BR-05513970 Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Journal of Biotechnology; v. 157, n. 1, p. 246-252, JAN 2012.
Web of Science Citations: 28
Abstract

Cellulase, an enzymatic complex that synergically promotes the degradation of cellulose to glucose and cellobiose, free or adsorbed onto Si/SiO(2) wafers at 60 degrees C has been employed as catalyst in the hydrolysis of microcrystalline cellulose (Avicel), microcrystalline cellulose pre-treated with hot phosphoric acid (CP), cotton cellulose (CC) and eucalyptus cellulose (EC). The physical characteristics such as index of crystallinity (I(C)), degree of polymerization (DP) and water sorption values were determined for all samples. The largest conversion rates of cellulose into the above-mentioned products using free cellulase were observed for samples with the largest water sorption values; conversion rates showed no correlation with either IC or DP of the biopolymer. Cellulose with large water sorption value possesses large pore volumes, hence higher accessibility. The catalytic efficiency of immobilized cellulase could not be correlated with the physical characteristics of cellulose samples. The hydrolysis rates of the same cellulose samples with immobilized cellulase were lower than those by the free enzyme, due to the diffusion barrier (biopolymer chains approaching to the immobilized enzyme) and less effective contact between the enzyme active site and its substrate. Immobilized cellulase, unlike its free counterpart, can be recycled at least six times without loss of catalytic activity, leading to higher overall cellulose conversion. (C) 2011 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 10/51219-4 - Interactions between macromolecules and surfaces
Grantee:Denise Freitas Siqueira Petri
Support Opportunities: Regular Research Grants