165. Abstract

A mutant strain of Acetobacter xylinum produces cellulose of anomalous band-like form ('native band'), and this material has been found to be cellulose II, presumably having a folded-chain structure (according to recent work by Kuga et al.). In addition to the previous results of electron diffraction, X-ray analysis showed that this band material to obtain additional evidence for the proposed structure. When hydrolysed with 1 N hydrochloric acid at 100 degrees C, the degree of polymerization (DP) of the material decreased rapidly from 322 (DPw/DPn = 3.83) to 18.3 (DPw/DPn = 1.19). The latter value (leveling-off DP) corresponds to the observed width (10 nm) of strand-like constituents of the band material. The sample dissolved in and regenerated from 8.75% aqueous sodium hydroxide lost its original characteristic morphology and became irregular-shaped agglomerates. The leveling-off of DP of this regenerated sample was 55.2 9ddPw/DPn=2.53), a typical value for common regenerated celluloses. These findings as a whole strongly suggest that the cellulose molecules in the native band are selectively cleaved at sharply folded parts by acid, producing fragments of the length of folding periodicity.

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