Fig. 6.

Number of glucan chains in cellulose microfibrils as a function of the s:i ratio. The minimum number of glucan chains for s:i values of 1.1, 1.2, 1.3, 1.4, and 1.5 are 30, 29, 28, 24, and 30, respectively (filled circles). (B) Representative cellulose microfibril cross sections with different s:i ratios. For each model, glucan chains from core cellulose (magenta), surface-bound cellulose (red), and surface cellulose (orange) are depicted. Structural models with 18 or fewer chains correspond to s:i ratios of 2.0 or higher and lack core cellulose, which are inconsistent with the experimental data.