To achieve rapid enrichment of the targeted hydrogen-producing bacterial population and reconstruction of the microbial community in the biological hydrogen-producing reactor, the activated sludge underwent multiple pretreatments using micro-aeration, alkaline treatment, and heat treatment. The activated sludge obtained from the multiple pretreatments was inoculated into the continuous stirred tank reactor (CSTR) for continuous operations. The community structure alteration and hydrogen-producing capability of the activated sludge were analyzed throughout the operation of the reactor. We found that the primary phyla in the activated sludge population shifted to Proteobacteria, Firmicutes, and Bacteroidetes, which collectively accounted for 96.69% after undergoing several pretreatments. This suggests that the multiple pretreatments facilitated in achieving the selective enrichment of the fermentation hydrogen-producing microorganisms in the activated sludge. The CSTR start-up and continuous operation of the biological hydrogen production reactor resulted in the reactor entering a highly efficient hydrogen production stage at influent COD concentrations of 4000 mg/L and 5000 mg/L, with the highest hydrogen production rate reaching 8.19 L/d and 9.33 L/d, respectively. The main genus present during the efficient hydrogen production stage in the reactor was , accounting for up to 33% of the total population. exhibited autoaggregation capabilities and a superior capacity for hydrogen production, leading to its prevalence in the reactor and contribution to efficient hydrogen production. During high-efficiency hydrogen production, flora associated with hydrogen production exhibited up to 46.95% total relative abundance. In addition, redundancy analysis (RDA) indicated that effluent pH and COD influenced the distribution of the primary hydrogen-producing bacteria, including , , and , as well as other low abundant hydrogen-producing bacteria in the activated sludge. The data indicates that the multiple pretreatments and reactor's operation has successfully enriched the hydrogen-producing genera and changed the community structure of microbial hydrogen production.

中文翻译：

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一种利用多重预处理和 CSTR 操作提高氢气产量的新型微生物群落重组策略


为了实现生物制氢反应器中目标产氢菌群的快速富集和微生物群落的重建，活性污泥经过微曝气、碱处理和热处理等多重预处理。将经过多次预处理得到的活性污泥接种到连续搅拌釜反应器（CSTR）中连续运行。分析了反应器运行过程中活性污泥群落结构的变化和产氢能力。我们发现，经过多次预处理后，活性污泥种群中的主要门类转变为变形菌门、厚壁菌门和拟杆菌门，合计占96.69%。这表明多重预处理有助于实现活性污泥中发酵产氢微生物的选择性富集。生物制氢反应器的CSTR启动和连续运行，使反应器在进水COD浓度4000mg/L和5000mg/L时进入高效制氢阶段，最高产氢率达到8.19L/分别为 d 和 9.33 L/d。反应器高效产氢阶段存在的主要属是 ，占总种群的 33%。表现出自动聚集能力和卓越的产氢能力，导致其在反应器中普遍存在并有助于高效产氢。在高效制氢过程中，与制氢相关的菌群总相对丰度高达46.95%。 此外，冗余分析（RDA）表明出水pH和COD影响主要产氢细菌的分布，包括 、 、 和 ，以及活性污泥中其他低丰度产氢细菌的分布。数据表明，多次预处理和反应器运行成功富集了产氢菌属，改变了微生物产氢的群落结构。