Complete Assignment of the CP/MAS 13C NMR Spectrum of Cellulose IIII

Abstract

For the assignment of 13C resonance for C2, C3, and C5 of cellulose IIII, 13C-enriched celluloses were biosynthesized by Acetobacter xylinum (A. xylinum) ATCC10245 in the culture medium containing d-(2-13C), d-(3-13C), or d-(5-13C)glucose. After the 13C-enriched celluloses and Cladophora cellulose were converted into IIII allomorph by the ethylenediamine treatment, cross-polarization/magic angle spinning (CP/MAS) 13C NMR spectra of these cellulose IIII samples were measured. By comparison of the CP/MAS 13C NMR spectrum of Cladophora cellulose sample with those of the 13C-enriched celluloses, 13C resonance lines of the cellulose IIII were completely assigned for the first time. As a result, all carbons of cellulose IIII were shown in singlet in the CP/MAS spectrum of cellulose IIII, which suggests that cellulose IIII is made up of one kind of glucopyranose residue.