Metagenomics, metatranscriptomics, and proteomics reveal the metabolic mechanism of biofilm sequencing batch reactor with higher phosphate enrichment capacity under low phosphorus load

Min Ni; Yang Pan; Dapeng Li; Yong Huang; Zhiqiang Chen; Lu Li; Zhen Bi; Ruijing Wu; Zuowei Song

doi:10.1016/j.envres.2023.117237

Metagenomics, metatranscriptomics, and proteomics reveal the metabolic mechanism of biofilm sequencing batch reactor with higher phosphate enrichment capacity under low phosphorus load

Environ Res. 2023 Dec 1;238(Pt 2):117237. doi: 10.1016/j.envres.2023.117237. Epub 2023 Oct 2.

Authors

Min Ni¹, Yang Pan², Dapeng Li³, Yong Huang³, Zhiqiang Chen⁴, Lu Li³, Zhen Bi³, Ruijing Wu⁵, Zuowei Song⁶

Affiliations

¹ 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.
² 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. Electronic address: panyang@mail.usts.edu.cn.
³ 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.
⁴ Harbin Institute of Technology, Harbin, 150006, China.
⁵ School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China.
⁶ Novoprotein, Suzhou, 215200, China.

PMID: 37793587
DOI: 10.1016/j.envres.2023.117237

Abstract

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/(m³·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_upt, P_rel, 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.

Keywords: Biofilm sequencing batch reactor; Low glycogen metabolism; Metagenomics; Metatranscriptomics; Phosphorus accumulating organisms; Proteomics.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adenosine Triphosphate
Biofilms
Bioreactors
NAD*
Phosphorus
Proteomics*
Sewage

Substances

polyhydroxybutyrate
NAD
Phosphorus
Adenosine Triphosphate
Sewage