Ma Jiangshan, Li Qiang, Wu Yujie, Yue Huimin, Zhang Yanghong, Zhang Jiashun, Shi Muling, Wang Sixian, Liu Gao-Qiang
Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, 410004, Hunan, People's Republic of China.
International Cooperation Base of Science and Technology Innovation On Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, 410004, Hunan, People's Republic of China.
Biotechnol Biofuels. 2021 Sep 25;14(1):189. doi: 10.1186/s13068-021-02040-7.
Lignin is a complex aromatic heteropolymer comprising 15-30% dry weight of the lignocellulose. The complex structural characteristic of lignin renders it difficult for value-added utilization. Exploring efficient lignin-degrading microorganisms and investigating their lignin-degradation mechanisms would be beneficial for promoting lignin valorization. In this study, a newly isolated white-rot basidiomycete, Trametes hirsuta X-13, with capacity to utilize alkaline lignin as the sole substrate was investigated.
The analysis of the fermentation properties of T. hirsuta X-13 using alkaline lignin as the sole substrate, including the mycelial growth, activities of ligninolytic enzymes and the rates of lignin degradation and decolorization confirmed its great ligninolysis capacity. The maximum lignin degradation rate reached 39.8% after 11 days of T. hirsuta X-13 treatment, which was higher than that of reported fungi under the same condition. Fourier transform infrared spectrometry (FTIR), gas chromatography-mass spectrometry (GC-MS) scanning electron micrographs (SEM), two-dimensional heteronuclear single quantum coherence NMR analysis (2D-HSQC NMR) collaborated with pyrolysis gas chromatography-mass spectrometry (py-GC/MS) analyses proved that lignin structure was severely deconstructed along with amounts of monomer aromatics generated. Furthermore, according to those chemical analysis, in addition to canonical C-C breakage, the cleavage of lignin interunit linkages of β-β might also occur by T. hirsuta X-13.
This study characterized a newly isolated white-rot basidiomycete T. hirsuta X-13 with impressive alkaline lignin degradation ability and provided mechanistic insight into its ligninolysis mechanism, which will be valuable for the development of lignin valorization strategies.
木质素是一种复杂的芳香族杂聚物，占木质纤维素干重的15%-30%。木质素复杂的结构特性使其难以进行高附加值利用。探索高效降解木质素的微生物并研究其木质素降解机制，将有助于促进木质素的增值利用。在本研究中，对新分离出的一种能够以碱性木质素作为唯一底物的白腐担子菌——毛栓菌X-13进行了研究。
以碱性木质素作为唯一底物对毛栓菌X-13的发酵特性进行分析，包括菌丝体生长、木质素分解酶活性以及木质素降解和脱色率，证实了其强大的木质素分解能力。经毛栓菌X-13处理11天后，木质素最大降解率达到39.8%，高于相同条件下已报道的真菌。傅里叶变换红外光谱（FTIR）、气相色谱-质谱联用（GC-MS）、扫描电子显微镜（SEM）、二维异核单量子相干核磁共振分析（2D-HSQC NMR）以及热解气相色谱-质谱联用（py-GC/MS）分析证明，随着大量单体芳烃的生成，木质素结构被严重解构。此外，根据这些化学分析，除了典型的C-C断裂外，毛栓菌X-13可能还会导致木质素β-β单元间连接键的断裂。
本研究对新分离出的具有显著碱性木质素降解能力的白腐担子菌毛栓菌X-13进行了表征，并对其木质素分解机制提供了机理见解，这对于开发木质素增值策略具有重要价值。
