黄翅大白蚁后肠几丁质降解微生物的分离与鉴定

Isolation and identification of chitin-degrading bacteria from the hindgut of Macrotermes barneyi

摘要:

【目的】从培菌白蚁——黄翅大白蚁后肠微生物菌群中分离能降解几丁质的细菌。【方法】以胶体几丁质为唯一碳源，根据胶体几丁质水解透明圈的大小进行筛选。通过形态学、生理生化以及16S rRNA基因序列分析进行菌株鉴定。【结果】从黄翅大白蚁肠道中筛选到8株能够降解胶体几丁质的细菌，它们分别属于芽孢杆菌属(Bacillus)、短芽孢杆菌属(Brevibacillus)、纤维单胞菌属(Cellulomonas)、指孢囊菌属(Dactylosporangium)、黄杆菌属(Flavobacterium)、类芽孢杆菌属(Paenibacillus)、鞘氨醇单胞菌属(Sphingomonas)和寡养单胞菌属(Stenotrophomonas)。8株菌均具有几丁质酶、β-葡萄糖苷酶和内切葡聚糖酶活性。【结论】从黄翅大白蚁后肠中获得8株能够降解胶体几丁质并具有其他碳水化合物降解酶活性的细菌，这一研究为了解白蚁肠道微生物协助白蚁消化食物机制提供了依据。

Abstract:

[Objective] This study aims to isolate and identify chitin-degradation bacteria from the hindgut of a fungus-growing termite Macrotermes barneyi. [Methods] Using an oligotrophic medium containing chitin as the only carbon source, chitin-degradation bacteria were screened and identified based on the transparent zone around the clone and morphological, physiological and biochemical properties as well as 16S rRNA gene sequence analysis. [Results] Eight chitin-degradation strains, which belong to Bacillus, Brevibacillus, Cellulomonas, Dactylosporangium, Flavobacterium, Paenibacillus, Sphingomonas and Stenotrophomonas, were isolated from the gut of M. barneyi. In addition to chitinase activity, the strains also exhibit β-glucosidase and endoglucanase activities. [Conclusion] Eight chitin-degradation strains, which also have other carbohydrate-active degradation activities, were obtained from the hindgut of M. barneyi. The study can help us understanding how gut symbionts facilitate termite in its food digest.