Affiliation:
1. College of Harbour and Coastal Engineering, Jimei University, Xiamen 361021, China
2. Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
Abstract
Anaerobic digestion (AD) represents one of the most eco-friendly approaches for recovering the energy from kitchen waste (KW). This study investigated the impact of humic acid (HA) on AD of KW. Batch experiments were conducted using KW as the substrate, with varying HA dosages. The results revealed that an increase in HA dosage led to an inhibition of methanogenic efficiency by 29.51% and a delayed start-up of AD. The HA exhibited dual effects on enzyme activities during AD, inhibiting hydrolytic enzymes while stimulating acidogenic enzymes. This unique interaction ultimately resulted in a significant 12.32% increase in volatile fatty acid production. Furthermore, HA induced the generation of reactive oxygen species and had a discernible impact on the activity of the electron transfer system. A bioinformatics analysis highlighted that HA promoted the abundance of microorganisms with mediated interspecies electron transfer ability, including DMER64 and Methanosaeta, as well as the Firmicutes phylum, while significantly reducing the abundance of Methanobacterium. Moreover, the KEGG pathway analysis revealed a decrease in hydrolysis and methanogenesis-related genes and an increase in acidogenesis-related genes.
Funder
Science and Technology Service (STS) Network Initiative Project of Fujian Province
Natural Science Foundation of China
Key Natural Science Foundation of Fujian
Subject
Plant Science,Biochemistry, Genetics and Molecular Biology (miscellaneous),Food Science