絮凝菌株Shinella sp.xn-1对铜绿微囊藻的絮凝效果

Flocculation effect of Shinella sp. xn-1 on Microcystis aeruginosa

【目的】研究絮凝功能细菌xn-1对有害水华藻——铜绿微囊藻的絮凝效果,以期为有害水华的治理提供新的选择。【方法】采用涂布划线法从藻际分离纯化絮凝功能微生物;基于16S r RNA基因序列确定进化地位;通过不同金属离子确定絮凝机制;梯度醇沉法获得絮凝物质;以酶标仪测定絮凝效率。【结果】菌株xn-1确定属于申氏杆菌属(Shinella),且命名为Shinella sp.xn-1。在添加Ca^(2+)作为促凝剂的条件下对铜绿微囊藻表现出高效的絮凝效果,其絮凝效果主要来源于胞外上清,而表现出高效的絮凝效果所需要的胞外上清添加量为3.0%。从胞外上清中获得的絮凝物质以0.5 g/L的添加量作用于藻细胞后表现出高效的絮凝效果,且随着处理时间增加,絮凝团的体积增大。【结论】Shinella sp.xn-1通过分泌胞外絮凝物质对铜绿微囊藻表现出高效的絮凝效果,在絮凝作用下藻细胞聚集在一起形成大体积的絮凝团,该研究有利于治理有害水华。

[Objective] To study the flocculation effect of bacterial strain xn-1 on water bloom causing species-Microcystis aeruginosa, to control water bloom. [Methods] Flocculation bacterium was isolated from phycosphere based on plate spread and streak technique; 16S rRNA gene was applied to determine the evolutionary status. Flocculation mechanism was confirmed by addition of different metal ions as coagulants. Biofloceulant was obtained by gradient alcohol precipitation. Microplate reader was used to study flocculation activity. [Resultsl Strain xn-1 was determined as a species of the genus Shinella, designated as Shinella sp. xn-1. Strain xn-1 exhibited high flocculation activity on M. aeruginosa with adding Ca2＋ as coagulants, and the flocculation activity was originated from extracellular supernatant, showing high flocculation efficiency with the concentration of 3.0%. Bioflocculant isolated from extracellular supematant could exhibit high flocculation effect with the addition of 0.5 g/L, and the algal flocs became huger with the increase of processing time. [Conclusion] Shinella sp. xn-1 shows high flocculation activity on M. aeruginosa through secreting extracellular bioflocculant, and the flocs with large volume are formed under the flocculation effect. This study is a useful option to control water blooms in the future.