Department of National Defense Architectural Planning & Environmental Engineering, Logistic Engineering University, Chongqing, 401311, China.
Department of National Defense Architectural Planning & Environmental Engineering, Logistic Engineering University, Chongqing, 401311, China.
Chemosphere. 2017 Dec;189:679-688. doi: 10.1016/j.chemosphere.2017.09.067. Epub 2017 Sep 22.
Extracellular polymeric substances (EPS) have be founded to participate in the process of enhanced biological phosphorus removal (EBPR), but the exact role of EPS in EBPR process is unclear. In this work, the roles of loosely-bound EPS (LB-EPS), tightly-bound EPS (TB-EPS) and microbial cell in EBPR were explored, taking the activated sludge from 4 lab-scale A/O-SBR reactors with different temperatures and organic substrates as objects. It was founded that the P of EBPR activated sludge was mainly stored in TB-EPS, but the P of non-EBPR activated sludge was primarily located in microbial cell. The P release and uptake of EBPR activated sludge was attributed to the combined action of TB-EPS and microbial cell. Furthermore, TB-EPS played an more important role than microbial cell in EBPR process. With the analysis of P NMR spectroscopy, both polyP and orthoP were the main phosphorus species of TB-EPS in EBPR sludge, but only orthoP was the main phosphorus species of LB-EPS and microbial cell. During the anaerobic-aerobic cycle, the roles of LB-EPS, TB-EPS and microbial cell in transfer and transformation of P in EBPR sludge were obviously different. LB-EPS transported and retained orthoP, and microbial cell directly anaerobically released or aerobically absorbed orthoP. Importantly, TB-EPS not only transported and retained orthoP, but also participated in biological phosphorus accumulation. The EBPR performance of sludge was closely related with the polyp in TB-EPS, which might be synthesized and decomposed by extracellular enzyme.
胞外聚合物（EPS）被发现参与了强化生物除磷（EBPR）过程，但 EPS 在 EBPR 过程中的确切作用尚不清楚。在这项工作中，以不同温度和有机底物的 4 个实验室规模的 A/O-SBR 反应器中的活性污泥为对象，探索了松散结合 EPS（LB-EPS）、紧密结合 EPS（TB-EPS）和微生物细胞在 EBPR 中的作用。研究发现，EBPR 活性污泥中的磷主要储存在 TB-EPS 中，而非 EBPR 活性污泥中的磷主要位于微生物细胞中。EBPR 活性污泥的磷释放和吸收归因于 TB-EPS 和微生物细胞的共同作用。此外，TB-EPS 在 EBPR 过程中的作用比微生物细胞更为重要。通过磷 NMR 光谱分析，发现无论是聚磷还是正磷都是 EBPR 污泥中 TB-EPS 的主要磷形态，但只有正磷是 LB-EPS 和微生物细胞的主要磷形态。在厌氧-好氧循环过程中，LB-EPS、TB-EPS 和微生物细胞在 EBPR 污泥中磷的迁移和转化方面的作用明显不同。LB-EPS 运输并保留正磷，而微生物细胞直接在厌氧条件下释放或在好氧条件下吸收正磷。重要的是，TB-EPS 不仅运输和保留正磷，还参与了生物磷的积累。污泥的 EBPR 性能与 TB-EPS 中的多聚体密切相关，这些多聚体可能是由胞外酶合成和分解的。
