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Ma G.,Shandong University | Pei H.,Shandong University | Pei H.,Shandong Provincial Engineering Center on Environmental Science and Engineering | Hu W.,Shandong University | And 2 more authors.
Journal of Pure and Applied Microbiology | Year: 2013

In order to offer useful information for harmless disposal of drinking water sludge, the bacterial community structures of sludge produced in two different drinking water plants were initially studied by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique. The result of sequencing of DGGE band analysis showed that the microbial community structure of drinking water sludge was complex, various types and a large number of microbes lived in drinking water sludge according to the Shannon-Wiener index of diversity (H) and the specific richness (R). Nine phyla obtained by the similarity analysis of 27 strong bands selected from the DGGE profiles sludge samples as follows: Proteobacteria, Acidobacteria, Fibrobacteres, Chloroflexi, Bacteroidetes, Firmicutes, Cyanobacteria, Verrucomicrobia and Sheathe bacteria. Among them, Proteobacteria contained two classes (Gamma-proteobacteria and Beta-proteobacteria) and then three genera (Rhodocyclus, Proteobacterium and Methylothermus) were the most common species. Chloroflexi including three classes [Chloroflexi, Caldilineae and Anaerolineae) and Bacteroidetes (Bacteroidetes and Flavobacteria) were also usual populations. Most of species, with high organic materials degradation activity, were heterotrophic bacteria due to a large number of organic materials contained in drinking water sludge. The present study also demonstrated the comparison of microbial community structure between drinking water sludge and wastewater sludge, Proteobacteria, Bacteroidetes and Chloroflexi were considered as the most common dominant species on phylum level, Differences such as the number of Rhodocyclu in drinking water sludge or Micrococcus in wastewater sludge were obviously shown due to the different treatment process and the inlet water quality. Source


Ma G.,Shandong University | Pei H.,Shandong University | Pei H.,Shandong Provincial Engineering Center on Environmental Science and Engineering | Hu W.,Shandong University | And 4 more authors.
Bioresource Technology | Year: 2014

The effects of environmental factors on cyanobacteria damage and microcystin-LR degradation in drinking water sludge were investigated under anoxic conditions. The rates of microcystin-LR release and degradation increased rapidly with the increasing temperature from 15. °C to 40. °C and the highest degradation rate of 99% was observed at 35. °C within 10. days. Compared to acidic conditions, microcystin-LR degraded more rapidly in weak alkali environments. In addition, the microbial community structures under different anoxic conditions were studied. The sequencing results showed that four phyla obtained from the DGGE profiles were as follows: Proteobacteria, Acidobacteria, Firmicutes and Cyanobacteria. Proteobacteria containing nine genera were the most common species. Pseudomonas, Methylosinus and Sphingomona all showed stronger activities and had significant increase as microcystin-LR degraded, so they should be responsible for the microcystin-LR degradation. This is the first report of Pseudomonas, Methylosinus and Sphingomonas as the microcystins-degrading microorganisms in anoxic drinking water sludge. © 2014 Elsevier Ltd. Source


Ma G.,Shandong University | Pei H.,Shandong University | Pei H.,Shandong Provincial Engineering Center on Environmental Science and Engineering | Hu W.,Shandong University | And 4 more authors.
Environmental Technology (United Kingdom) | Year: 2016

To enhance the degradation efficiency of microcystin (MC) in drinking water sludge (DWS), the underlying mechanisms between organic carbon (glucose) and the biodegradation of MC-LR under anoxic conditions were investigated by polymerase chain reaction-denaturing gradient gel electrophoresis technology. The addition of glucose reduced the rate of the MC-LR biodegradation indicating the occurrence of inhibition of degradation, and an increased inhibition was observed with increases in glucose concentration (0-10,000 mg/L). In addition, the community analysis indicated that the variety and the number of the microbes increased with the concentration of glucose amended (014-100014mg/L), but they decreased substantially with the addition of 10,00014mg/L of glucose. The phyla Firmicutes, Proteobacteria and Chloroflexi were found to be the dominant. Methylobacterium and Sphingomonas were MC-degrading bacteria and used glucose as a prior carbon source instead of MC, resulting in the decrease in the MC-LR biodegradation rate under anoxic conditions. Thus, reducing organic carbon could improve the anoxic biodegradation efficiency of MC in DWS. © 2015 Taylor & Francis. Source

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