Hydration and saccharification of cellulose Iβ, II and IIII at increasing dry solids loadings

Crystalline cellulose I beta (Avicel) was chemically transformed into cellulose II and IIII producing allomorphs with similar crystallinity indices (ATR-IR and XRD derived). Saccharifications by commercial cellulases at arrayed solids loadings showed cellulose IIII was more readily hydrolysable and less susceptible to increased dry solids levels than cellulose I beta and II. Analysis by dynamic vapor sorption revealed cellulose II has a distinctively higher absorptive capacity than cellulose I and IIII. When equally hydrated (g water/g cellulose), low-field nuclear magnetic resonance (LF-NMR) relaxometry showed that cellulose II, on average, most constrained water while cellulase IIII left the most free water. LF-NMR spin-spin relaxation time distribution profiles representing distinct water pools suggest cellulose IIII had the most restricted pool and changes in water distribution during enzymatic saccharification were most dramatic with respect to cellulose IIII compared to celluloses I beta and II.