Periodic peristalsis releasing constrained water in high solids enzymatic hydrolysis of steam exploded corn stover

• Water constraint was a main factor determining the high solids hydrolysis efficiency.
• Submicroscopic particulates and macro granule residues affected water constraint.
• Periodic peristalsis obviously released the constrained water before 24 h.
• Periodic peristalsis increased sugars conversion at high solids loadings.
• Periodic peristalsis was an effective method facilitating high solids hydrolysis.

Periodic peristalsis was used to release water constraint and increase high solids enzymatic hydrolysis efficiency. Glucan and xylan conversion in periodic peristalsis enzymatic hydrolysis (PPEH) at 21% solid loading increased by 5.2–6.4% and 6.8–8.8% compared with that in incubator shaker enzymatic hydrolysis (ISEH), respectively. Hydrolysis kinetics suggested that sugars conversion significantly increased within 24 h in PPEH compared with ISEH. The peak height of main water pool increased by 7.7–43.1% within 24 h in PPEH compared with ISEH. The increases in peak height of main water pool were consistent with the increases in glucan conversion. Submicroscopic particulates and macro granule residues contributed greatly to water constraint compared with glucose, xylose, ethanol, and Tween 80. Smaller particle size and longer residence time resulted in lower water constraint and facilitated the enzymatic hydrolysis performance. Periodic peristalsis was an effective method to reduce water constraint and increase high solids enzymatic hydrolysis efficiency.