Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, PR China.
Department of Chemical Engineering, University of Gujrat, Gujrat, 50700, Pakistan.
Chemosphere. 2022 Mar;291(Pt 3):132907. doi: 10.1016/j.chemosphere.2021.132907. Epub 2021 Nov 12.
The aggregation of anaerobic ammonium oxidation (anammox) bacteria is important for the start-up and biomass retention of anammox processes. However, it is unclear whether it is beneficial to the activity, growth and reproduction of anammox bacteria. In this study, four reactor systems were developed to explore the effects of aggregation on anammox activity, growth and reproduction, after excluding the contribution of aggregation to sludge settling and retention. Results demonstrated that (i) compared with free-living planktonic bacteria, the aggregated bacteria had a higher volumetric nitrogen removal rate (0.75 kg-N/(m³·d)) and specific nitrogen removal activity (1.097 kg-N/VSS/d). And after 67 days cultivation, it had the higher sludge concentration and relative abundance (92.4%); (ii) compared with acidic polysaccharides and α-d-glucopyranose polysaccharides, β-d-glucopyranose polysaccharide play more essential roles of anammox aggregation; (iii) norspermidine triggered the secretion of α-d-glucopyranose polysaccharides to combat the toxicity, and inhibited biomass growth rate; (iv) immobilization in polyvinyl alcohol (10%) or sodium alginate (2%) gel beads was better than sodium alginate-chitosan gel beads and norspermidine (biofilm inhibitor) for the cultivation of free-living planktonic anammox bacteria. This is the first comparative study of three methods for cultivating free-living anammox bacteria. In conclusion, we found that the aggregation of anammox sludge not only facilitates biomass retention but also enhances the bioactivity, relative abundance, growth, and reproduction rate of anammox bacteria. The work is helpful to understand the formation of anammox granular sludge and contribute to the fast start-up and stable operation in anammox application.
厌氧氨氧化（anammox）细菌的聚集对于 anammox 过程的启动和生物量保留很重要。然而，它是否有利于 anammox 细菌的活性、生长和繁殖尚不清楚。在这项研究中，开发了四个反应器系统，在排除聚集对污泥沉降和保留的贡献后，探索了聚集对 anammox 活性、生长和繁殖的影响。结果表明：（i）与自由生活的浮游细菌相比，聚集细菌具有更高的体积氮去除率（0.75kg-N/（m³·d））和特定氮去除活性（1.097kg-N/VSS/d）。并且在 67 天培养后，具有更高的污泥浓度和相对丰度（92.4%）；（ii）与酸性多糖和α-d-吡喃葡萄糖多糖相比，β-d-吡喃葡萄糖多糖在 anammox 聚集中发挥了更重要的作用；（iii）腐胺诱导α-d-吡喃葡萄糖多糖的分泌以抵抗毒性，并抑制生物量生长速率；（iv）在聚乙烯醇（10%）或海藻酸钠（2%）凝胶珠中的固定化优于海藻酸钠-壳聚糖凝胶珠和腐胺（生物膜抑制剂）用于培养自由生活的 anammox 细菌。这是首次对三种培养游离氨氧化菌的方法进行比较研究。总之，我们发现 anammox 污泥的聚集不仅有利于生物量保留，而且增强了 anammox 细菌的生物活性、相对丰度、生长和繁殖速度。这项工作有助于了解 anammox 颗粒污泥的形成，并有助于 anammox 应用中的快速启动和稳定运行。
