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Structural features of native cellulose gels and films from their susceptibility to enzymic attack
Author(s) -
Beltrame Pier Luigi,
Paglia Ernestina Dubini,
Seves Alberto,
Pellizzoni Elisabetta,
Romanò Maria
Publication year - 1992
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1992.070441204
Subject(s) - cellulose , microcrystalline cellulose , hydrolysis , xylose , substrate (aquarium) , yield (engineering) , crystallinity , bacterial cellulose , chemistry , polymer , chemical engineering , enzymatic hydrolysis , microcrystalline , polymer chemistry , materials science , chromatography , organic chemistry , composite material , crystallography , biology , fermentation , ecology , engineering
The reaction of enzymic hydrolysis has been used as a probe to evidence the different structural features of bacterial native cellulose gels and films synthesized from different carbon sources. The gels were found to be more hydrolyzable than were the films, both in terms of reaction extent and of initial reaction rate, by factors increasing with temperature. For instance, a cellulose gel synthesized from glucose showed at 50°C a hydrolysis yield twice as much as that of the corresponding film, thus revealing, in the former case, a higher level of substrate accessibility and enzyme penetrability. It has been suggested that the increase of gel accessibility with temperature can be associated with a corresponding lowering of the amount of structured water close to the polymer chains in the gel. The significant decrease of susceptibility to enzymic attack observed in going from the cellulose film obtained from glucose to that obtained from xylose has been related to the markedly lower value of specific surface area estimated in the latter case. Likely, in the film obtained from xylose, densely packed microfibrils occur that are scarcely accessible to enzyme. In some cases, the reaction progress has been followed by SEM analysis. Microcrystalline cellulose has been also considered for comparison.