The microbial mechanisms of enhanced humification by inoculation with Phanerochaete chrysosporium and Trichoderma longibrachiatum during biogas residues composting

This study investigated effects of composite microbes (CMs) (Phanerochaete chrysosporium and Trichoderma longibrachiatum) on humification during co-composting of biogas residue, spent mushroom substrate and rice straw. Results showed that CMs inoculation elevated degradation ratios of cellulose, hemicellulose and lignin by 7.86%, 8.87% and 6.45%, and contents of humus and humic acid were correspondingly promoted by 15.5% and 23.6%, respectively. Relative abundances of bacteria associated with refractory macromolecules degradation (Flavobacterium, Anseongella and Actinomadura) and cellulolytic fungi (Hypocreales_Incertae_sedis, Hypocreaceae and Psathyrellaceae) were raised by CMs addition. Redundancy analysis demonstrated a positive correlation between microbial communities and temperature, fulvic acid and lignocellulose contents. Moreover, CMs inoculation promoted pathways of xenobiotics biodegradation and metabolism, and biosynthesis of other secondary metabolites, which was closely associated with lignocellulose degradation and humus formation. These results suggested that biological inoculation could enhance composting efficiency and improve compost quality, benefiting biogas residues composting.

Automated summary

This study investigated the effects of composite microbes on humification during co-composting of biogas residue, spent mushroom substrate, and rice straw. The results showed that the inoculation of composite microbes increased the degradation of cellulose, hemicellulose, and lignin, as well as the content of humus and humic acid. The addition of composite microbes also increased the abundance of bacteria and fungi associated with the degradation of refractory macromolecules and cellulose, and promoted the pathways of xenobiotics biodegradation and metabolism.