Molecularly aggregated state of bacteria-produced cellulose made through nano-spinning

在标准培养条件下，木醋杆菌产生带状纤维素组装体，其平行于细菌细胞的长轴挤出，并含有富含纤维素Iα的晶体。与此相反，“密集”和“粗糙”的带状纤维素组件，这是垂直于细胞的长轴挤出，产生在HS培养基中在4 ℃或固化的HS培养基在28℃。通过TEM、AFM、X射线衍射分析和~（13）C固体核磁共振研究了纤维素的“致密”和“粗糙”带状组装体以及带状组装体的结构。“密集”和“粗糙”的带状组装体在由一种细菌产生的纤维素分子链的数量上是不同的。“致密”组件在电子和X射线衍射图中给出对应于纤维素II型晶体的结晶反射。负染色的“致密”带状组装体的显微照片表明，一个支架由结构单元组成，每个结构单元为6 - 9 nm x 10-22 nm。X射线衍射分析还表明，由三个正交反射估算的“致密”带状组装体的晶粒尺寸分别为6.6、6.7和8.2 nm，比铜纤维的晶粒尺寸大1.4 - 2倍。我们成功地获得了相同的带状组件的AFM和TEM图像。从AFM高度分布估计“密集”带状组件的高度为20-30 nm。结合AFM和TEM观察，获得了三维信息，阐明了带状组装体的形成过程

Under standard culture conditions, Acetobacter xylinum produces a ribbon-like cellulose assembly, which is extruded parallel to the long axis of the bacterial cell and contains cellulose Iα rich crystals. In contrast, 'dense' and' coarse' band-like cellulose assemblies, which are extruded perpendicularly to the long axis of the cell, are produced in HS medium at 4 ℃ or on solidified HS medium at 28℃ . Structures of 'dense' and 'coarse' band-like cellulose assemblies as well as ribbon-like cellulose assembly have been investigated by TEM, AFM, X-ray diffraction analysis, and carbon-13 solid-state NMR. 'Dense' and'coarse' band-like assemblies are different in the number of strands of cellulose molecules produced from one bacterium. The 'dense' assembly gives crystalline reflections corresponding to the cellulose II type crystal in the electron and X-ray diffraction diagrams. A micrograph of the negatively stained 'dense' band-like assembly indicates that a stand is composed of the structural units, each of which is 6 - 9 nm x 10-22 nm. A separate X-ray analysis also reveals that crystallite sizes estimated from the threee quatorial reflections are 6.6, 6.7, and 8.2 nm for 'dense' band-like assembly, which are 1.4 - 2 times larger than those of cupra rayon fibers. We succeeded in obtaining AFM and TEM images of the same band-like assemblies. The height of 'dense' band-like assemblies is estimated to be 20-30 nm from their AFM height profiles. By combining AFM and TEM observations, three-dimensional information is obtained to elucidate the formation process of band-like assemblies