Efficient decomposition of lignocellulose and improved composting performances driven by thermally activated persulfate based on metagenomics analysis

Highlights: • Self-generating heat during composting could activate persulfate to produce SO₄⁻·. • SO₄⁻· could accelerate the degradation of lignocellulose. • Actinobacteria and Proteobacteria were vital for lignocellulosic degradation. • GHs and AAs gene abundances were higher in PS than in CK by metagenomics analysis. In this study, fresh dairy manure and bagasse pith were used as raw materials to study the effect of potassium persulfate in the aerobic composting process. The influence of sulfate radical anion (SO₄⁻·) generated by thermally activated persulfate on physicochemical parameters, lignocellulose degradation, humic substance (HS) formation, microbial community succession, and carbohydrate-active enzymes (CAZymes) composition were assessed during composting. Experimental results showed that the degradation rates of cellulose, hemicellulose and lignin in the treatment group with potassium persulfate (PS) (61.47%, 74.63%, 73.1%) were higher than that in blank control group (CK) (59.98%, 71.47%, 70.89%), respectively. Additionally, persulfate additive promoted dynamic variation of dissolved organic matter (DOM) and accelerated the formation of HS. Furthermore, metagenomics analysis revealed that persulfate changed the structure of the microbial community, and the relative abundances of Actinobacteria and Proteobacteria increased by 17.64% and 34.09% in PS, whereas 12.09% and 29.96% in CK. Glycoside hydrolases (GHs) and auxiliary activities (AAs) families were crucial to degrade lignocellulose, and their abundances were more in PS. Redundancy analysis (RDA) manifested that Actinobacteria and Proteobacteria were closely associated with lignocellulosic degradation. In brief, persulfate could accelerate the degradation of organic components, promote the formation of HS, optimize the structure of microbial community, and improve the compost quality.