Sulfide is a toxic pollutant in the farming environment. Microbial removal of sulfide always faces various biochemical challenges, and the application of enzymes for agricultural environmental remediation has promising prospects. In this study, a strain of Cellulosimicrobium sp. was isolated: numbered strain L1. Strain L1 can transform S²⁻, extracellular enzymes play a major role in this process. Next, the extracellular enzyme was purified, and the molecular weight of the purified sulfur convertase was about 70 kDa. The sulfur convertase is an oxidase with thermal and storage stability, and the inhibitor and organic solvent have little effect on its activity. In livestock wastewater, the sulfur convertase can completely remove S²⁻. In summary, this study developed a sulfur convertase and provides a basis for the application in environmental remediation.

Applying exogenous additives during composting can help to effectively mitigate the environmental dissemination of antibiotic resistance genes (ARGs). Calcium peroxide (CaO₂)—a strong oxidizing agent—has achieved significant efficacy in degrading various pollutants. This study aims to evaluate the effects of CaO₂ at varying doses (0, 1% and 3% DW) on the variation in ARGs, mobile genetic elements (MGEs), and bacterial community succession during swine manure composting. Compared to the control (CK), adding 1% and 3% CaO₂ reduced total ARGs and MGEs by 50.29% and 64.62% in the LCP and by 68.96% and 79.74% in the HCP treatment, respectively. Adding 1% and 3% CaO₂ significantly increased the relative abundances (RAs) of Actinobacteriota and Firmicutes while decreasing those of Proteobacteria and Bacteroidetes during the thermophilic phase, especially under the high-dose treatment. Redundancy analysis (RDA) revealed that MGEs accounted for 54.20% of the total variation in ARGs, followed by environmental factors (30.3%). Network analysis further revealed that 1% and 3% CaO₂ treatments disrupted the association between ARGs and their host bacteria. Overall, adding CaO₂ can reduce the risks of spreading ARGs in compost products.

The complex chemical structure of plant lignin limits roughage utilization. Biological modification is commonly used to enhance lignin properties. Lentinus sajor-caju (L. sajor-caju) is a potent white-rot fungus for lignocellulose pretreatment in animal roughage. However, the key lignin-degrading enzyme genes remain unclear. This study evaluated the key enzyme genes involved in lignin degradation and their efficiency in decomposing alkaline lignin. Transcriptome and proteome comparative analyses of L. sajor-caju cultured in media with glucose and alkaline lignin as carbon sources revealed that the AA1 laccase aids lignin decomposition in L. sajor-caju. Additionally, a laccase heterologously expressing strain in Pichia pastoris X-33 was constructed. Compared with the wild-type L. sajor-caju strain W-2, Lac2 laccase activity increased by 67.35%. Electron microscopy showed that Lac2 degraded alkaline lignin, forming irregular pores and surface fusion. These findings indicate that Lac2 laccase has potential application value. In the future, it may be applied in agriculture, the chemical industry, and the energy sector to efficiently convert lignin into feed additives or energy products.