Evolution of cellulose crystals during prehydrolysis and soda delignification of sugarcane lignocellulose

Abstract

This work investigates the evolution of cellulose crystals from sugarcane lignocellulose (bagasse and leaves) submitted to prehydrolysis (hydrothermal, dilute acid, or steam explosion) and soda delignifications. Raw and treated materials are characterized by X-ray diffraction with modeling of area-detector patterns. Three treatment effects are correlated: increase in cellulose content, quantified by strong acid hydrolysis; increase in average cellulose crystallite width, inferred from sharper 200 diffraction peaks; and decrease in crystallite distortion, evidenced by d 200 -spacing approaching reference values. Crystal contents measured according to recent developments (in Driemeier and Calligaris, J Appl Cryst 44:184-192, 2011) are compared to cellulose contents. Limitations for this comparison are discussed. Results are consistent with minimum non-crystalline cellulose in raw lignocellulose, and with partial cellulose decrystallization or more defective crystallites in treated materials.

Understanding the mechanisms of cooperative physico-chemical treatment and mechanical disintegration of biomass as a route for enhancing enzyme saccharification

“…The rodlike nature of these structures may also mean that further reduction of longitudinal dimensions would achieve limited additional gain in accessible surface area and in digestion yield. X-ray diffraction measurements showed that some decrystallisation of the cellulose fibrils in all three biomass species was caused initially by hydrothermal treatment, from Table 4, which has been observed in earlier studies [37]. However, no further loss of crystallinity had occurred due to wet ball-milling, and in fact, there was a moderate increase in cellulose crystallinity, similar for all three biomass species, probably as a result of water-induced recrystallisation (hornification) due to the additional drying step required for XRD measurement [38].…”

Effects of Delignification on Crystalline Cellulose in Lignocellulose Biomass Characterized by Vibrational Sum Frequency Generation Spectroscopy and X-ray Diffraction

“…It should be noted that the apparent decrease of the XRD (200) peak width could also be caused by an increase in cellulose crystalline amount [26]. The increase in crystallite thickness has been reported to be caused by aggregation of cellulose microfibrils during heat treatments [9]. It is also noteworthy that the center of the XRD (200) peak has shifted slightly (2θ = 22.1°→ 22.4°) after the 130°C treatment and has remained constant after the introduction of oxygen reagent.…”

“…The peak center for pure microcrystalline cellulose Iβ is 22.8°. Hence, this slight shift of (200) peak towards pure cellulose peak position may imply the reduction of structural distortion of cellulose, potentially due to the removal or relocation of matrix components from cellulose crystallites [9].…”

“…In addition to the glycosidic bond cleavage, the delignification of lignocellulose could alter the aggregation of cellulose in the substrates [9,33]. For example, oxygen delignification has been shown to cause an increase in X-ray diffraction (XRD) crystallinity during the initial alkaline peeling reaction for pure cellulose samples such as cotton, Avicel, and fully bleached Kraft pulp [7].…”

Physical-chemical Characterization of Lignocellulosic Materials of Interest to Bioethanol Production

“…This evaluation should be made together with chrystallinity (Driemeier et al, 2011) and pre-treatment used. Important conclusion of this analysis is that the method is suitable for many different lignocellulosics, without modifications.…”