Abstract: There are abundant ellulose degrading bacteria in intestinal tract of larvae of Protaetia brevitarsis and they are capable of digesting and utilizing a large amount of lignocellulose. By using the Congo red staining method and filter paper degradation methods, Cellulomonas sp. strain h9 with strong cellulose degrading ability was isolated and identified by 16S rRNA analysis. The activity of the bacteria and its related enzymes were studied under different culture conditions, the results showed that strain h9 reached the stable growth state period after 120 h fermentation in liquid CMC-Na medium, and the maximum CMC enzyme activity was 0.19 U·mL^-1. The complete genome sequence of the strain h9 was obtained by genomic de novo sequencing, and the BLAST software was used to conduct a comparison analysis with the protein sequences in COG and CAZy databases. Key genes and pathways involved in the cellulose degradation, such as β-endoglucanases, β-glucosidases, and exoglucanases, were indentified. This study  provided the theoretical basis and experimental material for cellulose degrading enzymes and constructing cellulose degrading engineering bacteria.

Key words: cellulosic degrading bacteria, Protaetia brevitarsis larva, Cellulomonas sp., genome

摘要： 白星花金龟幼虫的肠道中含有丰富的纤维素降解菌，能够消化和利用大量的木质纤维素。通过刚果红染色法结合滤纸降解法，从其肠道中分离筛选出1株具有纤维素降解能力较强的纤维单胞菌（Cellulomonas sp.）h9。在不同培养条件下对该菌的生长及相关酶活性进行了研究，结果表明：在液体CMC-Na培养基中发酵120 h，菌体生长达到稳定期，CMC酶活性也在此时达到峰值为0.19 U·mL^-1。通过基因组de novo测序技术获取该菌的全基因组序列，经BLAST软件与GOG和CAZy数据库中的蛋白序列进行比对分析，确定菌株h9具有重要的纤维素降解相关基因及代谢通路，包括内切葡聚糖酶、β-葡萄糖苷酶、外切葡聚糖酶等。从而为筛选优质酶，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。

关键词: 纤维素降解菌, 白星花金龟幼虫, 纤维单胞菌, 基因组