Structure elucidation of uniformly ¹³C-labeled bacterial celluloses from different Gluconacetobacter xylinus strains

The morphological and supramolecular structures of native cellulose pellicles from two strains of Gluconacetobacter xylinus (ATCC 53582, ATCC 23769) were investigated. Samples had been statically cultivated in Hestrin-Schramm medium containing fully ¹³C-labeled β-d-glucose-U-¹³C₆ as the sole source of carbon. The results are compared with structure data of bacterial celluloses with a natural ¹³C abundance of 1.1%. Non-enriched and ¹³C-labeled cellulose pellicles formed crystalline structures as revealed by cross-polarized/magic-angle spinning (CP/MAS) ¹³C{¹H}-NMR and near infrared (NIR) FT-Raman spectroscopic measurements as well as wide-angle X-ray diffraction (WAXD) investigations. Atomic force microscopy (AFM) was applied for analyzing fiber morphologies and surface properties. For the first time, details about the manipulation of fiber widths and pellicle formation were shown for different bacterial strains of G. xylinus depending on the use of β-d-glucose-U-¹³C₆ for the biosynthesis.