酸碱调控污泥厌氧发酵实现乙酸累积及微生物种群变化

摘要：【目的】通过对污泥厌氧发酵pH调控，研究挥发性脂肪酸的累积、产酸微生物种群变化及产氢产乙酸菌群对乙酸产生的贡献。【方法】测定不同pH条件下污泥厌氧发酵过程中挥发性脂肪酸的累积；分别应用末端限制性片段长度多态性（T-RFLP）和荧光原位杂交技术（FISH）分析产酸系统中微生物种群结构的变化及产氢产乙酸菌的数量。【结果】 pH为10.0时，有机酸和乙酸的产率在发酵结束时分别达到652.6 mg COD/g-VS和322.4 mg COD/g-VS，显著高于其它pH条件。T-RFLP结果表明，pH值为12

Acetate accumulation and shift of bacterial community in anaerobic sewage sludge fermentation by pH adjustment

Abstract: Objective] To investigate the accumulation mechanism of volatile fatty acids (VFAs) the shift of bacterial community and the contribution of syntroph acetogenic bacteria during the anaerobic fermentation of sewage sludge under different pH values. Methods] The VFAs were determined at different pH conditions during the sludge anaerobic fermentation process. The Terminal Restriction Fragment Length Polymorph (T-RFLP) and Fluorescence In Situ Hybridization (FISH) were used to explore the variation of bacterial community and the quantity of syntroph acetogenic bacteria, respectively. Results] When the pH was controlled at 10.0, yields of VFAs and acetate were 652.6 mg COD/g-VS and 322 mg COD/g-VS,respectively (COD, Chemical Oxygen Demand; Volatile Solid, VS). They are much higher than that under neutral and acid pH conditions. The results by T-RFLP showed that Granulicatella was the dominant bacterial population at pH 12.0, while Peptostreptococcus dominated at pH 10.0. When the pH was adjusted from 7.0 to 3.0, the dominant bacterial populations were Clostridium and Bacillus, respectively. Based on the FISH result, the amount of syntrophic acetogenic bacteria at neutral condition was higher than that under the acid and alkali conditions. When the pH value was 10.0, the relative abundance was below 0.01% in total microorganism. Conclusions] pH not only altered the yields of VFAs and acetate, but also changed the bacterial community structure. Under the alkali condition, the VFAs accumulation was mainly from the hydrolysis fermenting bacteria. At the neutral and acid conditions, the syntroph acetogenic bacteria made more contribution for the acetate accumulation.