Bacterial cellulose preparation

E. Sourty, D. H. Rym, cuid R. H. Marchessault, Ferrite-loaded membranes of microfibrillar bacterial cellulose prepared by in situ precipitation. Chem. Mater. 10,1755-1757 (1998). 

The membrane is critically important in osomometry. Selection of a membrane involves reconciliation of high permeability toward the solvent with virtual impermeability to the smallest polymer molecules present in the sample. Membranes of cellulose are most widely used. Commercially Regenerated cellulose film is a common source. The undried gel cellophane film is often preferred, but the dry film may be swollen in water (or in aqueous solutions of caustic or zinc chloride ) to satisfactory porosity. Useful cellulose membranes may also be prepared by denitration of nitrocellulose films/ and special advantages have been claimed for bacterial cellulose films. The water in the swollen membrane in any case may be replaced by a succession of miscible organic solvents ending with the one in which osmotic measurements are to be made. Membranes of varying porosity may be... 

We wish to thank Dr. M. Takal of Hokkaido University for providing the bacterial strain and for his helpful suggestions for preparing the bacterial cellulose. We are also grateful to Mr. S. Nagata, Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, for assistance in the preparation of the bacterial cellulose. 

Native cellulose. Celluloses from purified Valonla ventricosa, Acetobaeter xylinium, ramie and cotton linters were used. Pellicles of bacterial cellulose were grown under the conditions described by Colvin (26) for 48-96 hours. The bacterial medium was thoroughly washed away with distilled water and 1% NaOH aqueous solution. A membrane of bacterial cellulose having uniaxial orientation was prepared from a young pellicle by stretching to about twice the initial length in a wet state and drying under tension. 

Cellulose II. Fortlsan, ordinary viscose rayon, mercerized ramie, mercerized bacterial cellulose, and saponified triacetate film were used. A film having uniaxial orientation was prepared from saponified triacetate film by stretching and drying under tension. 

Figures 1 and 2 show x-ray diffractograms of members of the cellulose I and II families, respectively. Diffractograms of each were typical, and Indicated complete transformation and uniplanar orientation of (110) relative to the membrane surface. It was remarkable to retain this orientation of the mercerized bacterial cellulose and of the lllu and IVjj prepared from it. The crystallinity of members of the cellulose II family were not high. But their IR spectra showed enough resolution for detailed discussion.

Fig. 2 X-ray diffractograms of the allomorphs in cellulose in II family by the reflection method. A II, mercerized bacterial cellulose, B IVu prepared from A through IIIn (C), C IIIn prepared from A. The treatments were carried out under stretching.

Figures 8 and 9 show solid state 13q nmr spectra of the allomorphs in the I family prepared from ramie and those in the II family prepared from Fortisan. The signal of Cl for IIIj- and IVj did not show enough resolution to split into peaks though there was a shoulder at about 105 ppm. For all allomorphs in the I family, the chemical shifts of the Cl signal ranged from 106.5 to 107.0 ppm and their half-widths were 250 Hz. The Cl signals for the II family were all split into two peaks at 106 and 108.5 ppm. The half-widths were 320, 330 and 290 Hz, for II, HIn and IVj-j, respectively. Larger widths were observed for the cellulose II family. The values of the chemical shift and half-width were averages of values measured for the samples with the various origins, except for the Valonia and bacterial celluloses, which had substaintially different values.

Hirai, A., Inui, O., and Horii, F. (2008). Phase separation behavior in aqueous suspensions of bacterial cellulose nanocrystals prepared by sulfuric acid treatment, Lanamuir. 25(1), 497-502. 

Zhang, S., and Luo, J. (2011). Preparation and properties of bacterial cellulose/alginate blend bio-fibers,/. Eng. Fiber. Fabr., 6,69-72. 

Preparation and characterization of a Bacterial cellulose/Chitosan composite for potential biomedical application, 18,... 

Kim et al. studied the effect of bacterial cellulose on the transparency of PLA/bacterial nanocomposites, since bacterial cellulose had shown good potential as reinforcement or preparing optically transparent materials due to its structure, which consists of ribbon-shaped fibrils with diameters in the range from 10 to 50 nm. They found that light transmission of the PLA/bacterial cellulose nanocomposite was quite high due to the size effect of... 

Recently, bacterial cellulose, produced by Acetobacter Xylinum, was used as reinforcement in composite materials with a starch thermoplastic matrix [230]. The composites prepared with bacterial cellulose displayed better mechanical properties than those with vegetable cellulose fibers. 

Jung, R., Jin, H.-J. Preparations of silk fibroin/bacterial cellulose composite films and their mechanical properties. Key Eng. Mater. 342-343, 741-744 (2007)... 

Tome, L.C., Brandao, L., Mendes, A.M., Silvestre, A.J.D., Neto, C.P., Gandini, A., Freire, C.S.R., Marrucho, I.M. Preparation and characterization of bacterial cellulose membranes with tailored surface and barrier properties. Cellulose 17(6), 1203-1211 (2010)... 

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