College of Bioscience and Biotechnology, Jiangxi Agricultural University, Nanchang, 330045, PR China.
Innovation Center of Pesticide Research, Department of Applied Chemistry, College of Sciences, China Agricultural University, Beijing 100193, China.
Environ Pollut. 2023 Apr 1;322:121230. doi: 10.1016/j.envpol.2023.121230. Epub 2023 Feb 6.
The key to the efficient removal of pulping wastewater lies in the effective degradation of lignin at high temperature. There is thus an urgent need to seek effective eco-environmental techniques to overcome this environmental limit for lignin degradation. The soil isolate thermophilic Serratia sp. AXJ-M efficiently metabolizes lignin. Nevertheless, the underlying comprehensive molecular mechanism of lignin degradation by thermophilic AXJ-M is poorly understood. Here, strain AXJ-M showed excellent degradation ability toward diverse lignin-related aromatic compounds. Functional genome analysis and RNA-Seq disclosed several traits which in joint consideration suggest a high efficiency of AXJ-M representative to the lignin degradation and environmental adaptation. Multiomics analyses combined with GC-MS revealed seven potential lignin biodegradation pathways. DyP was predicted to be involved in the breakdown of the β-O-4 ether bond, Cα-Cβ bond and Cα oxidation of lignin by prokaryotic expression and gene knockout and complementation. Molecular docking deepens the understanding of the interaction between DyP and lignin. Toxicity assessment experiments clearly indicated that AXJ-M significantly reduced the toxicity of the metabolites. This work expands the knowledge about the degradation mechanism of thermophilic lignin-degrading bacteria, most importantly, offers a new perspective on potential applications in utilizing this strain in pulping wastewater bioremediation.
制浆废水高效去除的关键在于高温条件下木质素的有效降解。因此，迫切需要寻求有效的生态环保技术来克服木质素降解的这一环境限制。土壤分离的嗜热沙雷氏菌 AXJ-M 能够有效地代谢木质素。然而，人们对嗜热 AXJ-M 木质素降解的综合分子机制还知之甚少。在这里，AXJ-M 菌株对各种木质素相关的芳香族化合物表现出了优异的降解能力。功能基因组分析和 RNA-Seq 揭示了几个特征，综合考虑表明 AXJ-M 代表了一种高效的木质素降解和环境适应能力。多组学分析结合 GC-MS 揭示了七种潜在的木质素生物降解途径。通过原核表达、基因敲除和互补实验预测 DyP 参与了木质素的 β-O-4 醚键、Cα-Cβ 键和 Cα 氧化的断裂。分子对接加深了对 DyP 与木质素相互作用的理解。毒性评估实验清楚地表明，AXJ-M 显著降低了代谢物的毒性。这项工作扩展了对嗜热木质素降解细菌降解机制的认识，最重要的是，为利用该菌株进行制浆废水生物修复提供了新的视角。
