Feng Shugeng, Tan Chuan Hao, Constancias Florentin, Kohli Gurjeet S, Cohen Yehuda, Rice Scott A
The Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore.
The School of Materials Science and Engineering, Nanyang Technological University, Singapore 637551, Singapore.
FEMS Microbiol Ecol. 2017 Apr 1;93(4). doi: 10.1093/femsec/fix020.
We recently isolated and characterised a predatory Bdellovibrio bacteriovorus strain from activated sludge (Ulu Pandan Water Reclamation Plant, Singapore), and this strain, B. bacteriovorus UP, was able to prey upon a broad spectrum of bacterial isolates from the activated sludge when grown as planktonic cells or as biofilms. Here, we have tested the effect of Bdellovibrio predation on floccular and granular sludge to determine if the spatial organisation, loosely or tightly aggregated communities, was protective from predation. The effect of predation was assessed using a combination of biomass quantification, cellular activity measurement and microscopic image analysis to determine community viability. Additionally, changes in the microbial communities due to predation by B. bacteriovorus UP were analysed through total RNA sequencing. Predation led to a significant reduction in microbial activity and total biomass for both floccular and granular sludge communities. Predation was also associated with significant changes in the microbial community composition in both communities, with >90% of the community members reduced in relative abundance after 24 h. Of those community members, the dominant organisms, such as Proteobacteria and Bacteroidetes, were the most affected phylotypes. This suggests that predatory bacteria, which display indiscriminant feeding, could significantly shift the species composition and thus, may disturb the operational performance of wastewater treatment systems.
我们最近从活性污泥（新加坡乌鲁班丹水回收厂）中分离并鉴定了一株捕食性食菌蛭弧菌，该菌株食菌蛭弧菌UP，在以浮游细胞或生物膜形式生长时，能够捕食活性污泥中广泛的细菌分离株。在此，我们测试了蛭弧菌捕食对絮状污泥和颗粒污泥的影响，以确定空间组织，即松散或紧密聚集的群落，是否能抵御捕食。使用生物量定量、细胞活性测量和显微镜图像分析相结合的方法评估捕食效果，以确定群落活力。此外，通过总RNA测序分析了食菌蛭弧菌UP捕食导致的微生物群落变化。捕食导致絮状污泥和颗粒污泥群落的微生物活性和总生物量显著降低。捕食还与两个群落中微生物群落组成的显著变化有关，24小时后，超过90%的群落成员相对丰度降低。在这些群落成员中，优势生物，如变形菌门和拟杆菌门，是受影响最大的系统发育型。这表明，表现出无差别摄食的捕食性细菌可能会显著改变物种组成，从而可能扰乱废水处理系统的运行性能。
