一份南海深海沉积物样品中可培养细菌的多样性

Diversity of cultured bacteria isolated from a deep see sediment in South China Sea

海洋沉积环境蕴含丰富的微生物资源。对深海难培养微生物的分离培养,不仅有利于深海微生物资源的挖掘与利用,也有利于对深海微生物学的研究。本研究采用多种培养基分离获得细菌菌株纯培养,并通过16S r RNA基因序列鉴定,对我国南海海域1个4 000 m水深的深海表层沉积物样品的可培养细菌多样性进行初探。共设计23种分离培养基,经过选择性分离培养最终获得612株细菌菌株,分别隶属于厚壁菌门（Firmicutes）、放线菌门（Actinobacteria）和拟杆菌门（Bacteroidetes）的9目10科27个属级类群,可培养优势类群为厚壁菌门,占所有分离物种数量的85.8%,包含13个16S r RNA基因序列相似性低于98%的潜在新物种。海洋琼脂类培养基适合培养不同种类的海洋细菌类群,放线菌选择性分离类合成培养基对放线菌类群的分离效果较好。最终获得一些与具有产抗生素、细胞毒素、高效酶活、耐受不良环境、降解污染物等特殊功能微生物相近的菌株。研究结果表明,该深海沉积物样品的可培养微生物资源、潜在新物种和微生物生理特性丰富多样,研究深海环境难培养微生物的分离策略及其微生物适应生理特性对研究极端环境微生物打下了基础。

Microbial resources are abundant in marine sedimentary environment. Researches on the isolation strategies for uncultured groups not only promote the microbial resource exploitation from the unusual environments,but also help to understand their role in deep sea. In this study,a deep sea sediment,collected from South China Sea at a water depth of 4 000 m,was used for bacterial diversity analysis based on cultured -dependent method and 16 S rRNA gene sequencing. By using 23 designed media,612 strains in total were isolated and identified,which affiliated to 9 orders,10 families and 27 genera in three phyla：Firmicutes,Actinobacteria and Bacteroidetes. Strains in phylum Firmicutes were the easiest group to be recovered from the deep-sea sediment and covered 85.8% of the total isolates,with 13 potential novel species. The diluted marine agar（MA） medium was suitable to isolate normal single - cell bacteria,and actinobacterial isolation agar（AIA）dilution medium was more suitable for actinobacteria growth. Many strains in this study had the highest similarities with the known species with the characteristics of antibiotic production,cytotoxin production,highly effective enzyme activity,tolerance to adverse environments,and degradation of pollutants.The preliminary results indicate that the cultivatable bacteria,potential novel species and microbial physiologic features are abundant and diverse in the deep - sea sediment. Research on the isolation strategies for uncultured groups and the adaptability of microorganisms to marine habitats will promote the microorganism recovery from the extreme environments.