Spatial structure characteristic analysis of corn stover during alkali and biological co-pretreatment using XRD

• Spatial structure change of corn stover is not uniform with time during alkali–biological pretreatment process.
• Crystalline areas and amorphous areas showed periodic changes.
• Dynamic periodic variation of crystallinity of corn stover was observed.
• Dynamic periodic variation of microcrystalline size of cellulose was observed.

Dynamic variation in the spatial structure of corn stover during alkali and biological co-pretreatment was investigated by X-ray diffraction. The result for crystallinity and microcrystalline size of cellulose showed periodic changes during the pretreatment process. The dominant destruction periods of crystalline areas were mainly located at 3–5 d and 7–17 d, and prevailing destroyed amorphous areas mainly occurred at 0–2 d and 5–7 d. On day 7, the relative crystallinity and microcrystalline size reached 52.81% and 8.56 nm, respectively, which were the maximum and minimum values during the whole co-pretreatment. The results indicated that spatial structure change was not uniform with pretreatment time, and this was contributed to explore the vital time point of destruction during the alkali–biological pretreatment.