Molecular characterization of anaerobic sulfur-oxidizing microbial communities in up-flow anaerobic sludge blanket reactor treating municipal sewage

Abstract

A novel wastewater treatment system consisting of an up-flow anaerobic sludge blanket (UASB) reactor and a down-flow hanging sponge (DHS) reactor with sulfur-redox reaction was developed for treatment of municipal sewage under low-temperature conditions. In the UASB reactor, a novel phenomenon of anaerobic sulfur oxidation occurred in the absence of oxygen, nitrite and nitrate as electron acceptors. The microorganisms involved in anaerobic sulfur oxidation have not been elucidated. Therefore, in this study, we studied the microbial communities existing in the UASB reactor that probably enhanced anaerobic sulfur oxidation. Sludge samples collected from the UASB reactor before and after sulfur oxidation were used for cloning and terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA genes of the bacterial and archaeal domains. The microbial community structures of bacteria and archaea indicated that the genus Smithella and uncultured bacteria within the phylum Caldiserica were the dominant bacteria groups. Methanosaeta spp. was the dominant group of the domain archaea. The T-RFLP analysis, which was consistent with the cloning results, also yielded characteristic fingerprints for bacterial communities, whereas the archaeal community structure yielded stable microbial community. From these results, it can be presumed that these major bacteria groups, genus Smithella and uncultured bacteria within the phylum Caldiserica, probably play an important role in sulfur oxidation in UASB reactors.

Diversity Profile of Microbes Associated with Anaerobic Sulfur Oxidation in an Upflow Anaerobic Sludge Blanket Reactor Treating Municipal Sewage

“…The number of representatives of the phyla Caldiserica and Chloroflexi was markedly lower, whereas that of the phylum Proteobacteria was only slightly higher than those in the earlier period. A previous study ( 1 ) showed that the uncultured bacteria of phylum Caldiserica were the main bacterial group observed in the UASB reactor, which was consistent with the results observed in this study. However, in the initial and second anaerobic sulfur oxidation periods, the number of representatives of the phylum Caldiserica decreased.…”

“…These consortia, which mediate AOM with sulfate, were composed of anaerobic methanotrophic (ANME) archaea and SRB ( 24 ). Although ANME-related archaea were not detected in the UASB reactor, methanogenic archaea and SRB were detected, as reported previously by Aida et al ( 1 ). This finding suggested that SRB that were present in the UASB reactor acted as the main players in anaerobic sulfur oxidation.…”

Sewage Sludge Microbial Structures and Relations to Their Sources, Treatments, and Chemical Attributes

“…Several bacteria associated with Fe reduction were identified, such as Acidithiobacillus , Ferrimicrobium , and Nitrospira ( Figure 1B ). In parallel, S reduction generates energy in anaerobic environments ( Aida et al, 2014 ); and it is crucial in structuring microbial community. It could be ratified by relative high abundance of Desulfobulbus and presence of Desulfovibrio as well as Desulfococcus , Desulforhabdus , and Desulfovirga in the samples ( Figure 1C ).…”

Phosphorus Release from Agricultural Drainage Sediments with Iron-Added Sediment Microbial Fuel Cells

“…On the other hand, Thiobacillus can remove N from sediment by denitrification [74]. Additionally, Aida et al [75] showed that the genus Smithella was possibly able to aid in the sulfur oxidation in up-flow anaerobic sludge blanket reactors. In this study, the operation of SMFC probably supported S 2− oxidation at the anode.…”