【摘要】 为了解生物结皮的微生物组成及影响碳素循环的微生物,文中在采用高通量技术研究西夏王陵生物结皮的微生物群落结构的基础上,采用选择培养基从生物结皮中分离产漆酶的微生物。研究结果表明:细菌的多样性显著高于真菌;变形菌门、酸杆菌门、蓝细菌门、放线菌门、拟杆菌门是绝对优势的细菌门类,子囊菌门和担子菌门是绝对优势的真菌门类;微鞘藻属、藓杆菌属、鞘氨醇单胞菌属、甲基杆菌属在细菌中占比较大的属,链格孢属、菌刺孢属、热子囊菌属、亚脐菇属等是主要的真菌,这些类群在稳定生物结皮结构、碳氮循环、有机物代谢等方面发挥了重要作用。以愈创木酚为唯一碳源从生物结皮中获得能利用愈创木酚的细菌10株,基于丁香醛联氮氧化的颜色反应,筛选出产漆酶能力最强的菌株C01和C06,基于16S rDNA序列的分子鉴定表明,两菌株均为芽孢杆菌。更多还原

【Abstract】 High-throughput technology was employed to explicit the bacterial and fungal community composition based on the V3+V4 regions of 16 S rDNA and ITS1 region of 18 S rDNA in the biological soil crusts collected from the Western Xia Imperial Tombs. To obtain the microorganisms affecting the carbon cycle in the biological soil crust, isolation, screening, and identification of laccase producing microorganisms from the soil crust were further carried out. Results showed the diversity of bacteria was significantly higher than that of fungi. The overall phylum-level composition of bacterial community was dominated by Proteobacteria, Acidobacteria, Cyanobacteria, Actinobacteria, and Bacteroidetes, while the fungal community was dominated by Ascomycota and Basidiomycota. On the genus-level, the bacteria were divided into 145 different genera and dominated by Microcoleus, Sphingomonas, Bryobacter, Methylobacterium. On the class-level, the fungi were divided into 83 different genara and dominated by Alternaria, Mycocentrospora, Thermoascus, Omphalina, et al. The predominant groups maybe play an important role in stabilizing the structure of biological soil crusts, carbon and nitrogen cycling, and the metabolism of organic matter. The selective culture medium using guaiacol as the sole carbon source was applied to isolate the laccase producing strains. Plate-screening of the target strains was conducted based on the oxidation of syringaldehyde and the selected strain was identified via 16 S rDNA sequencing. Ten strains with the potential of laccase production were isolated and two strains were screened as the laccase producing microorganisms. The phylogenetic tree of 16 S rDNA showed both the two strains belonged to Bacillus sp.更多还原