Department of Military Installation, Army Logistics Academy of the People's Liberation Army, University Town, Shapingba District, Chongqing, 401311, China.
College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, University Town, Shapingba District, Chongqing, 401331, China.
Chemosphere. 2021 Sep;279:130912. doi: 10.1016/j.chemosphere.2021.130912. Epub 2021 May 18.
The characteristics of enhanced biological phosphorus removal (EBPR) process under the combined actions of intracellular and extracellular polyphosphate (polyP) were investigated with the P Nuclear Magnetic Resonance (NMR) and the fractionation extracting the loosely-bound and tightly-bound extracellular polymer substances (i.e., LB-EPS and TB-EPS) and bacterial cells in EBPR sludge. The hydrolysis/synthesis of extracellular and intracellular polyP was a key step of the phosphate migration and transformation in EBPR sludge. The orthophosphate (orthoP) produced from the intracellular and extracellular polyP anaerobic-hydrolysis was partially accumulated in the bacterial cells and TB-EPS, and then the accumulated orthoP was main composition for these polyP aerobic-synthesis. Importantly, the anaerobic-hydrolysis enhancement of intracellular and extracellular ployP could promote EBPR sludge to absorb volatile fatty acids (VFAs) followed by being transformed into intracellular poly-hydroxy-alkanoates (PHAs). The mechanism for VFAs passing through the LB-EPS and TB-EPS should be an anion-exchange action between orthoP and VFAs. The orthoP accumulation in the TB-EPS kept an orthoP concentration gradient among the TB-EPS, LB-EPS and bulk solution, driving orthoP and VFAs migrations. The orthoP accumulation in the bacterial cells could keep an orthoP concentration difference between the cell-membrane two sides of phosphorus accumulating organisms (PAOs) to promote VFAs passing through the cell membrane considered as an anion exchange membrane. The intracellular PHAs continuously hydrolyzed accompanied with the average chain-length increases of the extracellular and intracellular polyP during the whole aerobic stage. Additionally, the energy of the extracellular polyP synthesized in situ should came from the intracellular PHAs hydrolysis.
采用 P 核磁共振（NMR）和分步提取松散结合和紧密结合胞外聚合物物质（即 LB-EPS 和 TB-EPS）以及 EBPR 污泥中细菌细胞的方法，研究了细胞内和细胞外多磷酸盐（polyP）共同作用下增强生物除磷（EBPR）过程的特性。胞外和胞内 polyP 的水解/合成是 EBPR 污泥中磷迁移和转化的关键步骤。来自胞内和胞外 polyP 厌氧水解的正磷酸盐（orthoP）部分在细菌细胞和 TB-EPS 中被部分积累，然后积累的 orthoP 是这些 polyP 好氧合成的主要成分。重要的是，细胞内和细胞外 polyP 的厌氧水解增强可以促进 EBPR 污泥吸收挥发性脂肪酸（VFAs），然后将其转化为细胞内 poly-羟基烷酸（PHAs）。VFAs 通过 LB-EPS 和 TB-EPS 的机制应该是 orthoP 和 VFAs 之间的阴离子交换作用。TB-EPS 中 orthoP 的积累在 TB-EPS、LB-EPS 和主体溶液之间保持了 orthoP 浓度梯度，驱动了 orthoP 和 VFAs 的迁移。细菌细胞中 orthoP 的积累可以在聚磷菌（PAOs）的细胞膜两侧之间保持 orthoP 浓度差，促进被认为是阴离子交换膜的 VFAs 通过细胞膜。在整个好氧阶段，细胞内 PHAs 不断水解，同时胞外和胞内 polyP 的平均链长增加。此外，原位合成的胞外 polyP 的能量应该来自细胞内 PHAs 的水解。
