深渊沉积物中盐单胞菌(Halomonas sp.)NyZ771菌株的分离培养及其降解芳香酸的研究

Isolation of a bacterium degrading aromatic acids from hadal trench sediment

摘要:

【背景】海洋是地球上最大的碳库，也是地球生物最大的栖息地。在这个庞大的生态系统中拥有多种多样的微生物，它们在全球碳循环中扮演了重要的角色。海斗深渊(海平面6 000 m以下的海域)由于高静水压和表层沉积汇集了大量有机质，形成了包含丰富生物资源的特殊生境。【目的】从马里亚纳海沟海斗深渊沉积物样品中分离培养能够以芳香酸为唯一碳源和能源生长的微生物，并研究其降解特性。【方法】通过模拟原位高压环境富集培养和常压条件下芳香酸选择性分离培养获得深渊来源的纯培养细菌，并根据形态学观察和16S rRNA基因序列系统发育分析进行种属鉴定，利用不同芳香酸进行培养和生物转化，通过HPLC和LC/MS鉴定芳香酸代谢中间产物。【结果】从马里亚纳海沟6 300 m沉积物样本中分离获得了一株盐单胞菌(Halomonas sp.)NyZ771。该菌株能够利用苯甲酸和4-羟基苯甲酸作为唯一碳源生长。其代谢4-羟基苯甲酸的中间产物鉴定为原儿茶酸。【结论】从深渊沉积物样本分离得到一株能降解苯甲酸和4-羟基苯甲酸的盐单胞菌NyZ771，丰富了深渊来源的微生物资源，为今后研究深渊中微生物的芳香酸降解及海洋微生物驱动的碳循环提供了一定的理论基础。

关键词:海斗深渊;微生物分离;芳香酸;原儿茶酸途径

Abstract:

[Background] The ocean is the largest reservoir of carbon and the largest habitat for life on the Earth. This vast ecosystem harbors a wide variety of microorganisms that play a key role in the global carbon cycle. Hadal trench (6 000 m below the sea level) is a special habitat containing rich biological resources owing to the high hydrostatic pressure and the accumulation of massive organic matter by surface deposition. [Objective] To obtain the bacterial pure culture capable of utilizing aromatic acids as the sole carbon and energy from the hadal trench sediment samples, and analyze its aromatic acid-degrading characteristics. [Methods] The hadal trench sediment sample was cultivated in the simulated in situ high-pressure environment, and then the culture was incubated on the plates with different aromatic acids under atmospheric ambient pressure. Finally, the bacterial pure culture was selected and identified based on the morphological characteristics and the phylogenetic tree constructed with the 16S rRNA gene. The strain was then incubated with different aromatic acids, and the degradation intermediates were identified by HPLC and LC/MS. [Results] A strain capable of utilizing benzoate and 4-hydroxybenzoate was isolated from the sediment sample from Mariana trench (6 300 m below the sea level). It belonged to the genus Halomonas and was designated Halomonas sp. strain NyZ771. The intermediate in 4-hydroxybenzoate degradation was identified as protocatechuate. [Conclusion] A benzoate- and 4-hydroxybenzoate-degrading bacterium, Halomonas sp. strain NyZ771, was isolated from the trench sediment. This study enriches the microbial resources derived from the hadal trench and provides a theoretical foundation for the future research on the aromatic acid degradation in hadal trenches and the carbon cycle driven by microorganisms in the ocean.

Key words:hadal trench;microbial isolation;aromatic acids;protocatechuate pathway