School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China; Jiangsu Key Laboratory of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China.
School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China; National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, Suzhou University of Science and Technology, Suzhou, 215009, China.
Environ Res. 2023 Dec 1;238(Pt 2):117237. doi: 10.1016/j.envres.2023.117237. Epub 2023 Oct 2.
The biofilm sequencing batch reactor (BSBR) process has higher phosphate recovery efficiency and enrichment multiple when the phosphorus load is lower, but the mechanism of phosphate enrichment at low phosphorus load remains unclear. In this study, we operated two BSBR operating under low and high phosphorus load (0.012 and 0.032 kg/(m·d)) respectively, and used metagenomic, metatranscriptomic, and proteomics methods to analyze the community structure of the phosphorus accumulating organisms (PAOs) in the biofilm, the transcription and protein expression of key functional genes and enzymes, and the metabolism of intracellular polymers. Compared with at high phosphorus load, the BSBR at low phosphorus load have different PAOs and fewer types of PAOs, but in both cases the PAOs must have the PHA, PPX, Pst, and acs genes to become dominant. Some key differences in the metabolism of PAOs from the BSBR with different phosphorus load can be identified as follows. When the phosphorus load is low, the adenosine triphosphoric acid (ATP) and NAD(P)H in the anaerobic stage come from the TCA cycle and the second half of the EMP pathway. The key genes that are upregulated include GAPDH, PGK, ENO, ppdk in the EMP pathway, actP in acetate metabolism, phnB in polyhydroxybutyrate (PHB) synthesis, and aceA, mdh, sdhA, and IDH1 in the TCA cycle. In the meantime, the ccr gene in the PHV pathway is inhibited. As a result, the metabolism of the PAOs features low glycogen with high PHB, P, P, and low PHV. That is, more ATP and NAD(P)H flow to phosphorus enrichment metabolism, thus allowing the highly efficient enrichment of phosphorus from low concentration phosphate thanks to the higher abundance of PAOs. The current results provide theoretical support and a new technical option for the enrichment and recovery of low concentrations of phosphate from wastewater by the BSBR process.
生物膜序批式反应器（BSBR）工艺在较低磷负荷时具有更高的磷回收效率和富集倍数，但低磷负荷下磷的富集机制仍不清楚。本研究分别在低磷负荷（0.012 kg/（m·d）和高磷负荷（0.032 kg/（m·d）下运行两个 BSBR，采用宏基因组、宏转录组和蛋白质组学方法分析生物膜中聚磷菌（PAOs）的群落结构、关键功能基因和酶的转录和蛋白表达以及细胞内聚合物的代谢。与高磷负荷相比，低磷负荷下的 BSBR 具有不同的 PAOs 和较少类型的 PAOs，但在这两种情况下，PAOs 必须具有 PHA、PPX、Pst 和 acs 基因才能成为优势菌。可以识别出不同磷负荷 BSBR 中 PAOs 代谢的一些关键差异如下：当磷负荷较低时，厌氧阶段的三磷酸腺苷（ATP）和烟酰胺腺嘌呤二核苷酸（NAD（P）H）来自三羧酸（TCA）循环和 EMP 途径的后半部分。上调的关键基因包括 EMP 途径中的 GAPDH、PGK、ENO 和 ppdk、乙酸代谢中的 actP、聚羟基丁酸（PHB）合成中的 phnB 以及 TCA 循环中的 aceA、mdh、sdhA 和 IDH1。同时，PHV 途径中的 ccr 基因受到抑制。因此，PAOs 的代谢特征是低糖原、高 PHB、P、P 和低 PHV。也就是说，更多的 ATP 和 NAD（P）H 流向磷富集代谢，从而使 BSBR 工艺能够从低浓度磷酸盐中高效富集磷。目前的结果为 BSBR 工艺从废水中富集和回收低浓度磷酸盐提供了理论支持和新的技术选择。
