Ozonolysis pretreatment of maize stover: The interactive effect of sample particle size and moisture on ozonolysis process

• Both particle size and moisture content had significant effects on ozonolysis.
• The ratio of free and bond water is a key factor for ozonolysis.
• Glucose yield after enzymatic hydrolysis increased as delignification rate increased.
• Washing ozonolyzed samples made no obvious difference to enzymatic digestibility.

Maize stover was ozonolyzed to improve the enzymatic digestibility. The interactive effect of sample particle size and moisture content on ozonolysis was studied. After ozonolysis, both lignin and xylan decreased while cellulose was only slightly affected in all experiments. It was also found that the smaller particle size is better for ozonolysis. The similar water activity of the different optimum moisture contents for ozonolysis reveals that the free and bound water ratio is a key factor of ozonolysis. The best result of ozonolysis was obtained at the mesh of −300 and the moisture of 60%, where up to 75% lignin was removed. The glucose yield after enzymatic hydrolysis increased from 18.5% to 80%. Water washing had low impact on glucose yield (less than 10% increases), but significantly reduced xylose yield (up to 42% decreases). The result indicates that ozonolysis leads to xylan solubilization.