Photogranulation in a Hydrostatic Environment Occurs with Limitation of Iron
Photogranulation in a Hydrostatic Environment Occurs with Limitation of Iron
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DOI：
10.1021/acs.est.0c07374
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发表时间：
2021-07-13
影响因子：
11.4
通讯作者：
Park, Chul
中科院分区：
文献类型：
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作者：
Ansari, Abeera A.;Ansari, Arfa A.;Park, Chul
丝状蓝藻是用于光合曝气颗粒废水处理的含氧光颗粒的基本元素。目前，该微生物群的选择机制及其在颗粒结构中的发育尚不清楚。在这里，我们研究了在静水环境中使用活性污泥 (AS) 接种物进行的光粒化中铁的特性和归宿。我们发现，由于接种物的腐烂，散装液体（Fe-BL）中的铁含量急剧增加，但随着微藻的繁殖和有氧环境的出现而迅速减少。与细胞外聚合物连接的铁（Fe-EPS）继续下降，但随着颗粒结构的出现而达到稳定的低值。 Fe-EPS 与蓝藻特异性色素之间存在很强的负相关性。光谱显示颗粒生物质中存在无定形氧化铁，这些氧化铁在光造粒过程中似乎保持不变。这些结果表明，藻华后，AS 接种物中 Fe-EPS 的可用性选择了蓝藻，并且该 Fe 库的限制成为蓝藻在静水环境中颗粒化的重要驱动因素。因此，我们认为铁的可用性对光造粒过程有很大影响。
Filamentous cyanobacteria are an essential element of oxygenic photogranules for granule-based wastewater treatment with photosynthetic aeration. Currently, mechanisms for the selection of this microbial group and their development in the granular structure are not well understood. Here, we studied the characteristics and fate of iron in photogranulation that proceeds in a hydrostatic environment with an activated sludge (AS) inoculum. We found that the level of Fe in bulk liquids (Fe-BL) sharply increased due to the decay of the inoculum but quickly diminished along with the bloom of microalgae and the advent of the oxic environment. Iron linked with extracellular polymeric substances (Fe-EPS) continued to decline but reached steady low values, which occurred along with the appearance of granular structure. Strong negative correlations were found between Fe-EPS and the pigments specific for cyanobacteria. Spectroscopies revealed the presence of amorphous ferric oxides in pellet biomass, which seemed to remain unaltered during the photogranulation process. These results suggest that the availability of Fe-EPS in AS inoculums-after algal bloom-selects cyanobacteria, and the limitation of this Fe pool becomes an important driver for cyanobacteria to granulate in a hydrostatic environment. We therefore propose that the availability of iron has a strong influence on the photogranulation process.