Abstract：
Exogenous quorum sensing (QS) molecular can regulate the activity and granulation process of anaerobic sludge in anaerobic digestion process, but would be impractical as a standalone operation. Here we demonstrated that application of 1 mg L-1 boric acid assisted in an upflow anaerobic sludge blanket (UASB) reactor recovery from volatile fatty acids (VFAs) accumulation. After VFAs accumulation, the chemical oxygen demand (COD) removal suddenly reduced from 78.98% to 55.86%. The relative abundance of acetoclastic methanogens decreased from 55.79% to 68.28%-23.14%∼25.41%, and lead to the acetate accumulate as high as 1317.03 mg L-1. Granular sludge disintegrated and the average size of sludge decreased to 586.38 ± 42.45 μm. Application of 1 mg L-1 boric acid activated the interspecies QS signal (AI-2) and then induced the secretion of intraspecies QS signal (N-acyl-homoserine lactones, AHLs). AHLs were then stimulated the growth of syntrophic acetate oxidizing bacteria and hydrogenotrophic methanogen. Moreover, the concentration of acetate decreased to 224.50 mg‧L-1, and the COD removal increased to 75.10% after application of 1 mg L-1 boric acid. The activated AI-2 may induce multiple quorum-sensing circuits enhance the level of AI-2 and AHLs in parallel, and in turn assisted in anaerobic digestion recovery from VFAs accumulation.
摘要：
外源群体感应(QS)分子可以调控厌氧消化过程中厌氧污泥的活性和颗粒化过程,但将是不切实际的作为一个独立的操作。在这里，我们证明了1mg·L-1硼酸的应用有助于上流厌氧污泥床（UASB）反应器从挥发性脂肪酸（VFA）积累中的回收。VFA积累后，化学需氧量(COD)去除率突然从78.98%降至55.86%。乙酸碎屑产甲烷菌的相对丰度从55.79%~68.28%下降到23.14%~25.41%，并导致乙酸盐积累高达1317.03mg·L-1。颗粒污泥分解，污泥平均粒径降至586.38±42.45μm。应用1mg·L-1硼酸激活种间QS信号（AI-2），然后诱导种内QS信号的分泌（N-酰基高丝氨酸内酯，AHLs).然后刺激AHLs的生长生养乙酸盐氧化细菌和氢营养型产甲烷菌。此外，施用1mg·L-1硼酸后，乙酸浓度降低至224.50mg·L-1，COD去除率提高至75.10%。激活的AI-2可以诱导多个群体感应电路并行增强AI-2和AHL的水平，反过来又有助于从VFAs积累中恢复厌氧消化。
