The bioaugmentation effect of microbial inoculants on humic acid formation during co-composting of bagasse and cow manure

• Published in: Environmental research 2024-07, Vol.252, p.118604-118604, Article 118604
• Main Authors: Lu, Mengling, Hao, Yuhao, Lin, Binfeng, Huang, Zhi, Zhang, Yu, Chen, Liang, Li, Kai, Li, Jianbin
• Format: Article
• Language: English
• Subjects: Carbohydrate-active enzymes genes; Compost quality; Humification process; Inoculation; Lignocellulose
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2024.118604

The effective degradation of recalcitrant lignocellulose has emerged as a bottleneck for the humification of compost, and strategies are required to improve the efficiency of bagasse composting. Bioaugmentation is a promising method for promoting compost maturation and improving the quality of final compost. In this study, the bioaugmentation effects of microbial inoculants on humic acid (HA) formation during lignocellulosic composting were explored. In the inoculated group, the maximum temperature was increased to 72.5 °C, and the phenol-protein condensation and Maillard humification pathways were enhanced, thus increasing the HA content by 43.85%. After inoculation, the intensity of the microbial community interactions increased, particularly for fungi (1.4-fold). Macrogenomic analysis revealed that inoculation enriched thermophilic bacteria and lignocellulose-degrading fungi and increased the activity of carbohydrate-active enzymes and related metabolic functions, which effectively disrupted the recalcitrant structure of lignocellulose to achieve a high humification degree. Spearman correlation analysis indicated that Stappia of the Proteobacteria phylum, Ilumatobacter of the Actinomycetes phylum, and eleven genera of Ascomycota were the main HA producers. This study provides new ideas for bagasse treatment and recycling and realizing the comprehensive use of resources. [Display omitted] •Inoculation increased compost temperature, and improved biological transformation.•The humic acid of group T eventually increased by 43.85% compared to group CK.•Actinomycetes and Ascomycota as key taxa were enriched in T for HA formation.•Inoculation can improve bacterial-bacterial and fungal-fungal interactions.•Bioaugmentation achieved the rapid composting humification process.