Abstract: Delignification is the key to improve the anaerobic digestion performance of vinegar residue. In this study, vinegar residue after anaerobic fermentation was used as substrate. The delignification was realized by post-treatment of vinegar residue with Phanerochaete chrysosporium, so as to deeply improve the methane production potential. The degradation and methane production potential of vinegar residue were investigated under different post-treatments (inoculation amount and post-treatment time). It was shown that increasing the inoculum amount and prolonging the post-treatment time could promote the secretion of lignocellulase, so as to obtain higher degradation effect. When the inoculation amount was 9 pieces and the post-treatment time was 16 days (experimental group T9-16), the substrate degradation efficiency was the highest. The degradation rates of total solids and violate solids were 8.96% and 9.91%, respectively. And the degradation rates of cellulose, hemicellulose and lignin reached 7.84%, 23.72% and 11.84%, respectively. Further experiments on the methane production potential showed that the biodegradability of vinegar residue was improved effectively by the post-treatment with P. chrysosporium. The optimal methane production was achieved in the experimental group T6-16 with 6 pieces of inoculation amount and 16 days of post-treatment time. The methane production per unit substrate (based on violate solids) of T6-16 reached up to 246.8 mL·g^-1, which was 2.82 times of that in the control group (vinegar residue without post-treatment). This study confirmed the feasibility of post-treatment with P. chrysosporium in promoting the anaerobic digestion efficiency of vinegar residue.

Key words: Phanerochaete chrysosporium, post-treatment, vinegar residue, lignocellulose, anaerobic digestion