Lignin degradation is important for enhancing the digestibility and improving the nutritive quality of ruminant feeds. White rot fungi are well known for their bioconversion of lignocellulosic biomass. The objective of this paper was to evaluate whether Lentinus sajor-caju, Pleurotus ostreatus, Phyllotopsis rhodophylla, Pleurotus djamor, Pleurotus eryngii, and Pleurotus citrinopileatus treatments altered the chemical compositions of highland barley straw constituents and enhanced their nutritional value as a ruminant feed. All white rot fungi significantly increased the relative crude protein (CP), ethyl ether extract (EE), starch, soluble protein (SP), and non-protein nitrogen (NPN) contents but decreased the ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and acid detergent insoluble protein (ADFIP) contents. In addition, L. sajor-caju treatment increased (p < 0.001) the levels of PA, PB₂, PB₃, CA, CB₁, CB₂, and CNSC, but reduced (p < 0.001) the PC and CC in the solid-state fermentation of highland barley straw. Maximum ligninlysis (50.19%) was optimally produced in the presence of 1.53% glucose and 2.29% urea at 22.72 ℃. The in vitro dry matter digestibility and total volatile fatty acid concentrations of fermented highland barley straw, as well as the fermentability, were optimized and improved with L. sajor-caju, which degraded the lignocellulose and improved the nutritional value of highland barley straw as a ruminant feed.

Lentinus sajor-caju has shown potential for the bioconversion of lignocellulosic biomass in various substrates. Here, we evaluated whether L. sajor-caju affects the lignocellulosic biomass, in vitro fermentation and antioxidant properties of Astragalus membranaceus var. mongholicus (AMM) stems. The lignocellulosic biomass content and the antioxidant activity of AMM stems were determined by scanning electron microscopy, chemical component analysis, in vitro fermentation and LC-MS metabolomics after 30 days of fermentation by L. sajor-caju at 25 °C. L. sajor-caju significantly altered the rigid structure of the stems. Compared with the control condition, the lignocellulose contents were significantly reduced (p < 0.001) and improved in vitro digestibility and total volatile fatty acids. In total, 624 differential metabolites, including 201 up-regulated and 423 down-regulated, were identified in unfermented and fermented comparison groups. Correlation analysis indicated that there were strongly correlations of the total phenolic content and total antioxidant capacity. Meanwhile, the differential metabolites were primarily associated with antioxidant activity, with 4(3H)-quinazolinone, dihydrocarvyl acetate and jaceoside being the most representative. In summary, L. sajor-caju altered the composition of the cell wall of AMM stems, thereby enhancing their antioxidant activity.

The value-added effect of white rot fungi on the feed of Astragalus membranaceus var. mongholicus (AMM) stems was explored. All four types of white rot fungi (Lentinus sajor-caju, Pleurotus ostreatus, Lentinula edodes, and Phanerodontia chrysosporium) reduced the lignocellulose content in AMM stems, improved in vitro dry matter digestibility (IVDMD), and influenced the activity of lignocellulose-degrading enzymes. Lentinus sajor-caju and Phanerodontia chrysosporium exhibited superior effects on lignin degradation and IVDMD and significantly altered non-volatile metabolites and antioxidant capacity. Lentinus sajor-caju fermentation resulted in the strongest antioxidant activity compared to that in the other fungal treatments. The fold change (FC) ratio (>100) of sakuranetin, 2′,6′-Di-O-acetylononin, isoformononetin, and artocarpin was compared between Lentinus sajor-caju and Phanerodontia chrysosporium. Among the phenolic compounds, flavonoids play a key role in antioxidant activity, with 5,6-Dihydroxy-7-methoxyflavone showing a strong correlation with antioxidant activity. This study provides valuable insights for utilizing AMM stem waste in the context of traditional Chinese medicine.

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.

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.