为了筛选出对生物絮团系统水质及菌群结构有积极作用的适宜浓度，本研究通过使用不同浓度的大豆低聚糖 (SBOS)替代葡萄糖 (GLU)作为生物絮团的碳源，对照组碳源为葡萄糖，实验组分别设置2.5%、5.0%、7.5%和10.0% SBOS (SBOS-2.5、SBOS-5.0、SBOS-7.5、SBOS-10.0组)替代葡萄糖为碳源。氯化铵为氮源，C/N 为 15，并添加枯草芽孢杆菌促进生物絮团系统形成。结果显示，各实验组与对照组均有效降低水中氨氮、亚硝态氮、硝态氮、总氮的浓度，各组之间均无显著差异。基于16S rRNA高通量测序，在门水平下，14 d时各实验组及对照组的优势菌门为变形菌门。28 d时，变形菌门与拟杆菌门的比例相近。属水平下，14 d时，SBOS-2.5组与SBOS-10.0组均显著提高芽孢杆菌属的丰度，显著降低气单胞菌科的丰度。28 d时，SBOS-2.5组与对照组和SBOS-10.0组相比显著提高黄杆菌属的丰度，各实验组与对照组相比显著降低金黄杆菌属的丰度。将菌群组成与环境因子关联分析，发现部分菌群对氮的硝化与反硝化有重要作用。研究表明，2.5%和10.0%的SBOS替代葡萄糖作为生物絮团的碳源均可有效提高有益菌丰度，降低有害菌丰度，有利于维持水体中细菌群落的稳定性。综合实验结果与生产应用成本，SBOS替代葡萄糖的推荐比例为2.5%。本研究为SBOS作为碳源应用于生物絮团系统提供基础，并为后续研究提供参考。

The study investigated the effects of soybean oligosaccharides (SBOS) on the microbial community structure within a biofloc system and identified the optimal concentration. The control group utilized glucose as carbon source, whereas experimental groups replaced it with 2.5%, 5.0%, 7.5%, and 10.0% SBOS, respectively. Ammonium chloride served as the nitrogen source with C/N ratio of 15, and Bacillus subtilis was introduced to establish the biofloc system. The results indicated that total nitrogen, ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen concentrations in the water were reduced, with no significant differences observed among all groups (P>0.05). High-throughput 16S rRNA sequencing revealed that Proteobacteria was the dominant phylum at 14 days in both experimental and control groups. By 28 days, Proteobacteria and Bacteroidota proportions were similar. At the genus level, Bacillus abundance significantly increased in the SBOS-2.5 and SBOS-10.0 groups at 14 days (P<0.05), while Aeromonadaceae abundance significantly decreased (P<0.05). At day 28, Flavobacterium abundance significantly increased in the SBOS-2.5 and SBOS-10.0 groups compared to the control group (P<0.05). Additionally, Chryseobacterium abundance in all experimental groups was significantly lower than control group (P<0.05). Some bacteria may be crucial in the nitrification and denitrification of nitrogen in water, according to a correlation analysis between bacterial composition and environmental conditions. In conclusion, substituting glucose with 2.5% and 10.0% SBOS as the carbon source in bioflocs effectively enhanced the abundance of beneficial bacteria and reduced that of harmful bacteria, thus promoting the stability of bacterial communities in water. Considering experimental outcomes and application costs, a 2.5% SBOS replacement ratio for glucose is recommended. This study provides a foundation for the practical application of SBOS as a carbon source in the biofloc systems and offers insights for future research.

S 966.9

浙江省农业重大技术协同推广计划 (2022XTTGSC01)；浙江省自然科学基金 (LTGN23C190002)