The study investigated the effects of methanogen pretreatment on pyrolysis behaviors of corn stalk (CS)
by using Py–GC/MS analysis and thermogravimetric analysis. Results indicated that biopretreatment
changed considerably the pyrolysis behaviors of CS from four weight loss stages to two weight loss
stages. Increasing biopretreatment time from 5 days to 25 days enhanced the kinds and contents of
chemicals in volatile products. In pyrolysis products, the contents of sugars, linear ketones and furans
decreased from 1.43%, 12.60% and 7.38% to 1.25%, 10.22% and 3.25%, respectively, and the contents of
phenols increased from 15.08% to 27.84%. The most content change from 6.83% to 13.63% indicated that
methanogen pretreatment improved the pyrolysis selectivity of CS to product the 4-VP, but it was disadvantageous
to 5-hydroxymethyl furfural, levoglucose and furfural. The changes of chemical compositions
and structure of CS after biopretreatment were the main reason of the differences.