2026-06-18 スウェーデン王立工科大学（KTH）
＜関連情報＞
- https://www.kth.se/en/om/nyheter/centrala-nyheter/method-to-extract-baltic-phosphorus-may-ease-europe-s-reliance-on-fertilizer-imports-1.1458411
- https://www.sciencedirect.com/science/article/pii/S0043135425017452
機能的微生物濃縮とキレート化促進による海洋堆積物からのリン放出：持続可能なリン管理に向けて Functional microbial enrichment and chelation-enhanced phosphorus release from marine sediments: Toward sustainable phosphorus management
Fengyi Zhu, Frederico Marques Penha, Zeynep Cetecioglu
Water Research Available online: 20 October 2025
DOI:https://doi.org/10.1016/j.watres.2025.124842
Graphical abstract
Highlights
- A dual-mode strategy enhanced P release via PAO inoculation and EDTA chelation.
- Over 80 % total P release and >98 % recovery were achieved in just 13 days.
- PAOs were rapidly enriched from 12.9 % to 65.0 % under EDTA exposure.
- Activation of core energy pathways potentially supporting PAO activity.
- EDTA enriched PAO P-uptake genes while suppressing GAO functional genes.
Abstract
To improve the efficiency of phosphorus (P) release from marine sediments and contribute to P loop closure, this study proposed a novel strategy combining bio-inoculation with polyphosphate-accumulating organisms (PAOs) and chemical enhancement via chelating agents. Based on prior findings, two-stage experiments were conducted. In Stage 1, anaerobic batch tests assessed the effect of different chelating agents for P release. While citrate showed no promoting effect, the addition of ethylenediaminetetraacetic acid (EDTA) significantly enhanced total P release, reaching 48.5 % within 15 days. In Stage 2, PAO-acclimated sediments were introduced into the system, followed by alternating anaerobic-aerobic fed-batch operation for 7 days, and subsequent EDTA addition with anaerobic incubation for another 6 days. This combined approach achieved a total P release efficiency 83.4 %, with final soluble P concentrations reaching 145.9 mg/L. During this process, PAOs were rapidly enriched, with their relative abundance increasing from 12.9 % to 65.0 %. Metagenomic analysis revealed that EDTA promoted environmental filtering, selectively enriching PAOs (Candidatus Accumulibacter) and thereby reinforcing their specific contributions to P functional genes. The resulting P-rich supernatant was then subjected to precipitation. PHREEQC simulations guided the prediction of optimal precipitation conditions, and laboratory experiments confirmed that most soluble P, especially Fe-bound forms, could be efficiently recovered, with maximum precipitation efficiencies of 98.8 %.
