《环境昆虫学报》

纤维素类生物质是地球上分布最为广泛的可再生资源，筛选高效的纤维素降解菌对于纤维素生物质资源的开发和利用具有重要的意义。采用刚果红染色法，从双叉犀金龟Allomyrina dichotoma3龄幼虫肠道筛选到58株纤维素降解菌，选择透明圈直径与菌株直径比值较大的菌株进行酶活力测定，综合刚果红染色法与酶活力测定结果，菌株M24产纤维素酶能力最强，其滤纸酶、内切葡聚糖苷酶、外切葡聚糖苷酶和β-葡萄糖苷酶，活力大小分别为13.14 U/mL、45.67 U/mL、18.29 U/mL、36.30 U/mL；通过16S rDNA序列比对分析，鉴定其为贝莱斯芽孢杆菌；通过基因组ONT测序技术获取该菌的全基因组序列，该菌株基因组全长4 290 258 bp，共注释到15个纤维素酶相关基因，其中包括4个内切-β-1,4葡聚糖酶基因（EC 3.2.1.4），9个β-葡萄糖苷酶（EC 3.2.1.91）相关基因，2个外切β-1,4葡聚糖酶（EC 3.2.1.91）相关基因。结果为构建纤维素降解工程菌提供了重要的理论依据和供试材料。

英文摘要:

Cellulosic biomass is the most widely distributed renewable resource on earth, and the screening of efficient cellulose-degrading bacterial strains is of great significance for the development and utilization of cellulosic biomass resources. We screened 58 cellulose-degrading bacteria from the 3rd instar larvae of Allomyrina dichotoma by Congo red staining method, and selected the strain with larger ratio of transparent circle diameter to strain diameter for enzyme activity determination, and obtained the strongest cellulase-producing strain M24 by combining the results of Congo red staining method and enzyme activity determination, which was identified as Bacillus velezensis through comparison and analysis of 16S rDNA sequence. The crude enzyme solution of this strain was determined to contain filter paper enzyme, endoglucosidase, exoglucosidase and β-glucosidase with high activities of 13.14 U/mL, 45.67 U/mL, 18.29 U/mL and 36.30 U/mL, respectively. The whole genome sequence of the strain was obtained by genome ONT sequencing technology, and the genome of the strain was 4 290 258 bp in length, and a total of 15 cellulase-related genes were annotated, including 4 endo-β-1,4 glucanase genes (EC 3.2.1.4), 9 β-glucosidase (EC 3.2.1.91)-related genes, and 2 exo β-1,4 glucanase (EC 3.2.1.91)-related genes, thus providing an important theoretical basis and test material for constructing cellulose degradation engineering bacteria.

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