Institute of Environmental Health and Ecological Safety, School of Environmental and Safety Engineering, Jiangsu University, Zhenjiang 212013, China E-mail:
Water Sci Technol. 2022 May;85(10):2899-2911. doi: 10.2166/wst.2022.161.
Current gel entrapment technology has certain advantages for the enrichment of anammox sludge. In this study, the optimal preparation conditions and cultivation equipment of Ca-alginate cell beads for the culturing anammox sludge were proposed. The preparation parameters of the Ca-alginate cell beads were as follows: 3% sodium alginate, 4% CaCl, V:V = 1:1, a drop height of 9 cm, stirring speed of 300 rpm, and cross-linking time of 24 h. The prepared cell beads were regular spheres with a uniform size and hard texture. Throughout the 9 days of cultivation, the number of anammox bacteria in the Ca-alginate cell beads was 4.3 times that of the initial sludge, and the color of the cell beads changed from yellowish-brown to reddish-brown. Scanning electron microscopy (SEM) analysis showed that the SA gel beads had a good microporous structure. The fluorescence in situ hybridization (FISH) results illustrated that the bacteria were mostly dispersed inside the Ca-alginate cell beads. Additionally, the qPCR results implied that only a relatively small amount of anammox biomass (2.74×10 copies/gel-bead) was required to quickly start the anammox process. The anammox bacteria in the Ca-alginate cell beads grew with a fast growth rate in a short period and exhibited high activity due to diffusion limitations. In addition, the anammox bacteria cultivated in the Ca-alginate cell beads could adapt to the increase in substrate concentration in a short period. The optimal incubation time of this gel entrapment method for anammox sludge was no more than 17 days under the experimental conditions of this work. Therefore, this simple and practicable gel entrapment method may serve as a suitable pre-culture means for the rapid enrichment of anammox bacteria.
目前的凝胶包埋技术在富集厌氧氨氧化污泥方面具有一定的优势。本研究提出了用于培养厌氧氨氧化污泥的最佳海藻酸钠包埋细胞珠的制备条件和培养设备。海藻酸钠包埋细胞珠的制备参数如下：3%海藻酸钠、4%CaCl2、V:V=1:1、滴头高度 9cm、搅拌速度 300rpm、交联时间 24h。制备的细胞珠为规则的球体，大小均匀，质地坚硬。在整个 9 天的培养过程中，厌氧氨氧化菌在海藻酸钠包埋细胞珠中的数量是初始污泥的 4.3 倍，细胞珠的颜色从黄褐色变为红棕色。扫描电子显微镜（SEM）分析表明，SA 凝胶珠具有良好的微孔结构。荧光原位杂交（FISH）结果表明，细菌主要分散在海藻酸钠包埋细胞珠内部。此外，qPCR 结果表明，仅需要相对少量的厌氧氨氧化生物量（2.74×10 拷贝/珠）就可以快速启动厌氧氨氧化过程。在短时间内，包埋在海藻酸钠细胞珠中的厌氧氨氧化菌以较快的生长速度生长，并由于扩散限制而表现出较高的活性。此外，在短时间内，包埋在海藻酸钠细胞珠中的厌氧氨氧化菌可以适应基质浓度的增加。在本工作的实验条件下，这种凝胶包埋法培养厌氧氨氧化污泥的最佳孵育时间不超过 17 天。因此，这种简单实用的凝胶包埋法可以作为快速富集厌氧氨氧化菌的合适预培养手段。
