1994 Fiscal Year Final Research Report Summary
Propeties of Native Cellulose II with Folded-Chain Structure
| Project/Area Number |
05453175
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
生物資源科学
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
KUGA Shigenori The University of Tokyo, Assistant professor, 農学部, 助手 (60012051)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KONDO Tetsuo Forestry & Forest Products Research Institute, Research Associate, 研究員
ISOGAI Akira The University of Tokyo, Associate professor, 農学部, 助教授 (40191879)
|
|---|
| Project Period (FY) |
1993 – 1994
|
| Keywords | Acetobater / Native band cellulose / Cellulose II / Folded-chaincrystal / Level-off degree of polymerization / Solid-state NMR |
|---|
| Research Abstract |
(1) Culture conditions for the native band-producing strain were established. The bulk material gave the X-ray diffraction pattern of well defined cellulose II.
(2) Leveling-off behavior on acid hydrolysis of native band cellulose was similar to those of other cellulose samples, but the former's leveling-off value (LODP) (18.4) was remarkably lower than others. When the native band cellulose was dissolved in and regenerated from concentrated alkali, its cahracteristic band morphology was lost and LODP changed to ca.50, a value similar to ordinary regenerated celluloses. These results strongly support the proposed model of regular chain folding in the native band with a periodicity of 10 nm.
(3) The typical thickness of native band was determined by shadowing technique as ca.10 nm.
(4) Analysis of the change in solid-state 13C NMR spectrum by acid hydrolysis of native band showed that the chain folding region involved irregular conformations of glucose residues, whose contribution to the spectrum coinciding with that of amorphous regions of other celluloses.
(5) These findings lead to a model of native band cellulose consisting of strand-like structures each composed of ca.16 glucan chains forming a monomolecular sheet, which is subsequently folded regularly.
|
