ISSN:
1572-882X
Keywords:
bacterial cellulose
;
Acetobactor xylinum
;
cellulose crystals
;
CPMAS13C NMR
;
FT-IR
;
xyloglucan
;
carboxymethyl cellulose
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract Effects of polymeric additives with different degrees of polymerization (DP) or substitution (DS) on the crystallization of celluloses Iα and Iβ have been examined at an early stage of the incubation of Acetobactor xylinum by using newly developed FT-IR spectroscopy. It was found that the mass fraction of cellulose Iα is greatly decreased with increasing concentrations of carboxymethyl cellulose sodium salt (CMC) or xyloglucan (XG) in the incubation medium. Such a decrease in the mass fraction of cellulose Iα, which corresponds to the enhanced crystallization of cellulose Iβ, is more prominent for CMC or XG with lower DPs, but the additives with too low DPs are not so effective probably due to higher solubility and the lower adhesion on the surface of microfibrils. Moreover, the mass fractions of celluloses Iα and Iβ are highly correlated with the crystallite size of microfibrils, indicating that Iα is crystallized in larger-size microfibrils while Iβ is produced in smaller-size microfibrils. On the basis of these experimental results, the mechanism of the crystallization of celluloses Iα and Iβ is discussed in the Acetobactor xylinum system.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02228804
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