Glycogen accumulating organisms(GAOs) are closely related to the deterioration of enhanced biological phosphorus removal systems. However, the metabolic mechanisms that drive GAOs remain unclear. Here, the two-thirds ...Glycogen accumulating organisms(GAOs) are closely related to the deterioration of enhanced biological phosphorus removal systems. However, the metabolic mechanisms that drive GAOs remain unclear. Here, the two-thirds supernatant of a reactor were decanted following the anaerobic period to enrich GAOs. Long-term monitoring demonstrated that the system was stable and exhibited typical characteristics of GAOs metabolism. Acetate was completely consumed after 60 min of the anaerobic phase. The level of glycogen decreased from 0.20 to 0.14 g/gSS during the anaerobic phase, whereas the level of glycogen significantly increased to 0.21g/gSS at the end of the aerobic period. Moreover, there was almost no phosphate release and absorption in the complete periods, thus confirming the successful construction of a GAOs enrichment system. Microbial community analysis demonstrated that Ca. Contendobacter was among the core functional genera and showed the highest activity among all of the communities. Furthermore, our study is the first to identify the involvement of the ethyl-malonyl-CoA pathway in the synthesis of polyhydroxyvalerate via croR, ccr, ecm, mcd, mch and mcl genes. The Embden-Meyerhof-Parnas(EMP) pathway was preferentially used via glgP. Furthermore, the glyoxylate cycle was the main source of ATP under anaerobic conditions, whereas the tricarboxylic acid cycle provided ATP under aerobic conditions. aceA and mdh appeared to be major modulators of the glyoxylate pathway for controlling energy flow. Collectively, our findings not only revealed the crucial metabolic mechanisms in a GAOs enrichment system but also provided insights into the potential application of Ca. Contendobacter for wastewater treatment.展开更多
Polymerase chain reaction （PCR）-denaturing gradient gel electrophoresis （DGGE） protocol was employed for revealing microbial community structure and succession in a sequential anaerobic and aerobic reactor perform...Polymerase chain reaction （PCR）-denaturing gradient gel electrophoresis （DGGE） protocol was employed for revealing microbial community structure and succession in a sequential anaerobic and aerobic reactor performing enhanced biological phosphorus removal （EBPR） during start-up period. High phosphorus removal was achieved after 15 d. On day 30, phosphorus removal efficiency reached to 83.2% and the start-up was finished. DGGE profiles of periodical sludge samples showed that dominant microbial species were 19 OTUs （operational taxonomy units）. Unweighted pair-group method using arithmetic averages （UPGMA） clustering analysis revealed that rapid community succession correlated to low phosphorus removal rate and high phosphorus removal efficiency reflected on steady community structure. Sequencing results indicated that determined sequences （12 OTUs） belonged to Proteobacterium, Actinobacteria, Gemmatimonadales and unaffiliate group. Proteobacterium, Tetrasphaera elongate and Gemmatimonas aurantiaca may act important roles in phosphorus removal. With little amount as known glycogen accumulating organisms, Candidatus Competibacter phosphatis still at accumulating-phase had limited effect on microbial community structure. When climax community was obtained, dominant microbes were 14 OTUs. Microbes in a large amount were uncultured bacterium Thauera sp., uncultured y-Proteobacterium and Tetrasphaera elongata.展开更多
基金supported by the National Natural Science Foundation of China (No.51678565)the Special Fund of China (No.AWS18J004)+1 种基金the Tianjin Natural Science Foundation (Nos.19JCYBJC_(2)3800, 19JCZDJC_(3)9800)the National Key R&D Program of China (No.2018YFD0800104)。
文摘Glycogen accumulating organisms(GAOs) are closely related to the deterioration of enhanced biological phosphorus removal systems. However, the metabolic mechanisms that drive GAOs remain unclear. Here, the two-thirds supernatant of a reactor were decanted following the anaerobic period to enrich GAOs. Long-term monitoring demonstrated that the system was stable and exhibited typical characteristics of GAOs metabolism. Acetate was completely consumed after 60 min of the anaerobic phase. The level of glycogen decreased from 0.20 to 0.14 g/gSS during the anaerobic phase, whereas the level of glycogen significantly increased to 0.21g/gSS at the end of the aerobic period. Moreover, there was almost no phosphate release and absorption in the complete periods, thus confirming the successful construction of a GAOs enrichment system. Microbial community analysis demonstrated that Ca. Contendobacter was among the core functional genera and showed the highest activity among all of the communities. Furthermore, our study is the first to identify the involvement of the ethyl-malonyl-CoA pathway in the synthesis of polyhydroxyvalerate via croR, ccr, ecm, mcd, mch and mcl genes. The Embden-Meyerhof-Parnas(EMP) pathway was preferentially used via glgP. Furthermore, the glyoxylate cycle was the main source of ATP under anaerobic conditions, whereas the tricarboxylic acid cycle provided ATP under aerobic conditions. aceA and mdh appeared to be major modulators of the glyoxylate pathway for controlling energy flow. Collectively, our findings not only revealed the crucial metabolic mechanisms in a GAOs enrichment system but also provided insights into the potential application of Ca. Contendobacter for wastewater treatment.
基金supported by the National Natural Science Foundation of China (No. 50508011).
文摘Polymerase chain reaction （PCR）-denaturing gradient gel electrophoresis （DGGE） protocol was employed for revealing microbial community structure and succession in a sequential anaerobic and aerobic reactor performing enhanced biological phosphorus removal （EBPR） during start-up period. High phosphorus removal was achieved after 15 d. On day 30, phosphorus removal efficiency reached to 83.2% and the start-up was finished. DGGE profiles of periodical sludge samples showed that dominant microbial species were 19 OTUs （operational taxonomy units）. Unweighted pair-group method using arithmetic averages （UPGMA） clustering analysis revealed that rapid community succession correlated to low phosphorus removal rate and high phosphorus removal efficiency reflected on steady community structure. Sequencing results indicated that determined sequences （12 OTUs） belonged to Proteobacterium, Actinobacteria, Gemmatimonadales and unaffiliate group. Proteobacterium, Tetrasphaera elongate and Gemmatimonas aurantiaca may act important roles in phosphorus removal. With little amount as known glycogen accumulating organisms, Candidatus Competibacter phosphatis still at accumulating-phase had limited effect on microbial community structure. When climax community was obtained, dominant microbes were 14 OTUs. Microbes in a large amount were uncultured bacterium Thauera sp., uncultured y-Proteobacterium and Tetrasphaera elongata.
