An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide isolated by phenol–water extraction of Pseudoalteromonas haloplanktis strain KMM 223 (44-1). l-Iduronic acid (IdoA) was found to be a component of the poly

Interactions between cellulose and glucomannan/galactomannans have been studied through molecular and ultrastructural analysis of composites formed by deposition of cellulose from Acetobacter aceti ssp. xylinum into solutions containing either glucomannan or galactomannans of varying Man:Gal ratio. 13C NMR suggests that unsubstituted mannan segments can bind to cellulose by undergoing a conformational transition to an extended 2-fold form. Konjac glucomannan induces a coalescence of cellulose fibrils and a dramatic reduction of crystallinity: low galactose galactomannans also show these trends. The inferred mannan/cellulose sandwich structure may underlie the densification processes which can accompany mannan-containing secondary cell wall formation. Medium galactose galactomannans additionally form cross-links of varying lengths between cellulose fibrils and show evidence for self-association. The presence of cellulose fibrils promotes network formation from galactomannan solutions under conditions where this would not normally occur. The principles of interaction between cellulose and mannan-based polymers at both molecular and ultrastructural levels are discussed in the context of plant cell wall design and assembly.