Nitrogen source-driven regulation of Irpex lacteus for enhanced lignocellulose degradation and microbial protein production in wheat straw

White rot fungi, such as Irpex lacteus, offer significant potential for lignocellulose degradation and protein synthesis in sustainable biofuel and animal feed production,but optimizing nitrogen sources to balance fungal growth, lignin degradation, and protein synthesis remains a critical challenge.This study investigated the effects of ammonium chloride (NH₄Cl) and sodium nitrate (NaNO₃) on I. lacteus fermentation in wheat straw, with a focus on the regulation of nitrogen source.Transcriptomic analysis revealed that NaNO₃ upregulated genes associated with nitrogen uptake and cellulose/hemicellulose degradation,while exerting less repression on key ligninolytic enzymes, such as manganese peroxidase and cytochrome P450, compared to NH₄Cl.These findings suggest that NaNO₃ enhances I. lacteus metabolism by harmonizing lignin degradation with efficient nitrogen conversion. To investigate the effects of different nitrogen sources on the fermentation of wheat straw by the fungus Tricholoma album, a study was conducted where ammonium chloride and sodium nitrate solutions were added as inorganic nitrogen sources. A control group was also set up by adding distilled water. Subsequently, transcriptional sequencing was performed on the fermentation samples.

白腐真菌（White rot fungi），如乳白耙齿菌（Irpex lacteus），在可持续生物燃料与动物饲料生产的木质纤维素降解及蛋白质合成领域具备显著应用潜力，但如何优化氮源以平衡真菌生长、木质素降解与蛋白质合成，仍是一项关键挑战。本研究以麦秆为发酵基质，探究了氯化铵（NH₄Cl）与硝酸钠（NaNO₃）对乳白耙齿菌发酵的影响，重点聚焦氮源的调控效应。转录组分析结果显示，相较于氯化铵，硝酸钠可上调与氮摄取、纤维素/半纤维素降解相关的基因，同时对锰过氧化物酶、细胞色素P450等关键木质素降解酶的抑制作用更弱。上述研究结果表明，硝酸钠可通过协调木质素降解与高效氮转化，提升乳白耙齿菌的代谢活性。为探究不同氮源对白蘑（Tricholoma album）麦秆发酵的影响，本研究设置了添加氯化铵与硝酸钠溶液作为无机氮源的实验组，并增设添加蒸馏水的空白对照组，随后对发酵样本开展转录组测序。