好氧反硝化聚磷菌的筛选及菌群构建优化

Screening and combination of aerobic denitrifying phosphorus-accumulating bacteria for waste removal

摘要:

【背景】近年来，随着海水养殖规模的扩大，养殖产品产生的排泄物与残留的饲料大量积累，导致养殖水域的氮磷元素含量上升，水体富营养化加剧并对环境造成危害。【目的】从红树林人工湿地中筛选出好氧反硝化聚磷菌株并研究各菌株的最佳除氮除磷效率，随后通过响应面法构建菌群，进一步强化菌株去除污染物的能力。【方法】将前期筛选出的5株耐盐异养硝化-好氧反硝化菌通过异染颗粒染色和聚-β-羟基丁酸(poly-β-hydroxybutyric acid, PHB)染色进行好氧反硝化聚磷菌的筛选，通过单因素试验明确各菌株的最佳除氮除磷条件，并利用Design-Expert软件和Box-Benhnken响应面法进行配比试验。【结果】经过筛选获得3株耐盐好氧反硝化聚磷菌，分别为肺无色杆菌(Achromobacter pulmonis) strain E43、氧化木糖无色杆菌(Achromobacter xylosoxidans) strain J1和食油假单胞菌(Pseudomonas oleovorans) strain F2，发现菌株E43具有聚磷功能，确定了耐盐好氧反硝化聚磷菌群的最优降解投加比例为E43:J1:F2=1:1:4，验证结果显示该菌群的平均氨氮(NH₄⁺-N)去除率和磷酸盐(PO₄^3--P)去除率分别为91.28%和93.03%。【结论】菌群的构建提升了PO₄^3--P的平均去除率，为后续在实际含盐污水中的应用提供了前期基础。本研究是对好氧反硝化聚磷菌群构建的有效尝试，为构建高效功能混合菌群提供一种科学的方法。

Abstract:

[Background] In recent years, the expansion of mariculture has caused the massive accumulation of excrement and residual feed, which has increased nitrogen and phosphorus content in aquaculture waters, aggravating eutrophication and causing harm to the environment. [Objective] To screen out the aerobic denitrifying phosphorus-accumulating strains from mangrove constructed wetlands, determine the optimal nitrogen and phosphorus removal efficiency of each strain, and then optimize the strain combination by response surface methodology to further improve pollutant removal. [Methods] From the 5 strains of salt-tolerant heterotrophic nitrifying-aerobic denitrifying bacteria isolated in our previous study, the aerobic denitrifying phosphorus-accumulating bacteria were screened by metachromatic granules staining and poly-β-hydroxybutyric acid (PHB) staining. The optimal nitrogen and phosphorus removal conditions of each strain were determined by single factor test. Box-Benhnken design was performed in Design-Expert to optimize the strain combination. [Results] Three strains of salt-tolerant aerobic denitrifying phosphorus-accumulating bacteria were screened out, which were Achromobacter pulmonis strain E43, Achromobacter xylosoxidans strain J1, and Pseudomonas oleovorans strain F2, respectively. E43 was found for the first time to have the function of phosphorus accumulation. The optimal strain combination was determined as E43:J1:F2=1:1:4. The average removal rates of ammonia nitrogen (NH₄⁺-N) and phosphate (PO₄^3--P) by this combination were 91.28% and 93.03%, respectively. [Conclusion] The bacterial strain combination improved the average removal rate of PO₄^3--P, which provided a preliminary basis for the subsequent application in the actual treatment of saline wastewater. This study is an effective attempt for the assembly of aerobic denitrifying phosphorus-accumulating bacteria and provides a feasible method for the assembly of efficient functional bacteria.