Behavior of cellulose production of Acetobacter xylinum in 13C-enriched cultivation media including movements on nematic ordered cellulose templates

Acetobacter xylinum NQ-5 (ATCC 53582) and AY-201 (ATCC 23769) cultivated in the Hestrin-Schramm medium containing D-glucose with a natural C-13-abundance of 1.1% were investigated regarding their cell division rates and the bacterial movements. Comparative studies were carried out in the presence Of D-glucose-U-C-13(6) with a uniform C-13-labeling of 99% as the sole carbon source. The bacterial growth rates in numbers were found to increase in the C-13-enriched media by about 13% for NQ-5 and 26% for AY-201, respectively. The movements of single cells caused by the inverse force of the secretion and deposition of cellulose nanofibers on nematic ordered cellulose (NOC) templates were investigated by real-time video analyzes using light microscopy. As a result, D-glucose-U-C-13(6) reduced the speed of motion for both strains, which was an opposite trend to the above growth rates in the cell division. The deposited cellulose fibers were proved to be in a cellulose crystalline form by CP/MAS C-13 NMR and NIR FT Raman spectroscopic measurements, although the biosynthesized and thereafter-deposited cellulose has a strong interaction with the surface of NOC. (c) 2005 Elsevier Ltd. All rights reserved.