The effect of the different P/C ratios, i. e. , 2.9/100, 1.4/100, 0.57/100, 0. 29/100, 1.4/100 and 2.9/100, on the dynamic changes of the phosphorus removal as well as the organism community was examined in an anaerobic/aerobic sequencing batch reactor (A/O-SBR) system, affiliated with Polymerase Chain Reaction-denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results showed that when the P/C ratio dropped ( 2. 9/100→ 1.4/100→0. 57/100→0.29/100 ) gradually, the P-release to substrate-uptake ratios decreased companied by an increase in the intracellular glycogen content. Also, the DGGE profiles showed that with the decrease of the influent P/C ratios the dominant microbial species increased from 11 operation taxonomy units (OTUs) to 14 OTUs, and then dropped to 7 OTUs. Judged from the biochemical characteristics of the SBR, it can be confirmed that the predominant microbial populations in the SBR had changed from PAOs to PAOs and GAOs co-exist, and finally to GAOs. For the last recovery period, the P-release to substrate-uptake ratios increased gradually with the decrease of the intracellular glycogen content, indicating that PAOs can be recultivated through regulating the influent P/C ratio, once GAOs had dominated the EBPR system. While, the DGGE profiles showed that the dominant species of PAOs re-cultivated from the GAOs-dominated system was different greatly from both the GAOs-dominated system and the initial PAOs-dominated system.%通过调节进水ρ(P)/ρ(C)的不同水平(2.9/100、1.4/100、0.57/100、0.29/100、1.4/100和2.9/100),考察了A/O-SBR系统强化生物除磷效果的动态变化;同时利用PCR-DGGE分子生物学技术,研究了聚磷菌和聚糖菌种群的竞争与演变.结果表明,当ρ(P)/ρ(C)逐渐降低时(2.9/100→1.4/100→0.57/100→0.29/100),吸收单位碳源的厌氧释磷量逐渐降低,而胞内糖原量逐渐升高.相应的DGGE图谱显示,微生物类群在p(P)/ρ(C)降低过程由11 OTUs升高到14 OTUs,最后降至7 OTUa;结合生化指标判断,系统优势菌种呈现的是从聚磷菌占优势、聚糖菌聚磷菌共存到聚糖菌占优势的动态变化.随后,提高进水ρ(P)/ρ(C)值从0.29/100到1.4/100再到2.9/100,污泥吸收单位碳源的厌氧释磷量逐渐升高,而胞内糖原量逐渐降低.这说明当聚糖菌占优势以后,通过调节ρ(P)/ρ(C)可重新培养获得聚磷菌优势系统,但DGGE图谱也显示,此时的聚磷菌优势种群较聚糖菌系统的优势种群已有较大变化,且与先前聚磷菌系统的优势种群也不尽相同.
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