Thauera and Azoarcus as functionally important genera in a denitrifying quinoline-removal bioreactor as revealed by microbial community structure comparison

Abstract

Structural shifts associated with functional dynamics in a bacterial community may provide clues for identifying the most valuable members in an ecosystem. A laboratory-scale denitrifying reactor was adapted from use of non-efficient seeding sludge and was utilized to degrade quinoline and remove the chemical oxygen demand. Stable removal efficiencies were achieved after an adaptation period of six weeks. Both denaturing gradient gel electrophoresis profiling of the 16S rRNA gene V3 region and comparison of the 16S rRNA gene sequence clone libraries (LIBSHUFF analysis) demonstrated that microbial communities in the denitrifying reactor and seeding sludge were significantly distinct. The percentage of the clones affiliated with the genera Thauera and Azoarcus was 74% in the denitrifying reactor and 4% in the seeding sludge. Real-time quantitative PCR also indicated that species of the genera Thauera and Azoarcus increased in abundance by about one order of magnitude during the period of adaptation. The greater abundance of Thauera and Azoarcus in association with higher efficiency after adaptation suggested that these phylotypes might play an important role for quinoline and chemical oxygen demand removal under denitrifying conditions.

Application of molecular techniques to evaluate the methanogenic archaea and anaerobic bacteria in the presence of oxygen with different COD:Sulfate ratios in a UASB reactor

“…was involved in the cycle of sulfur compounds, probably using the S1 that was identified in the sludge blanket of the UASB reactor. Uncultured bacterium (AY945891) was previously identified from the secondary sedimentation tank of wastewater from a coking and chemical treatment plant (Shangai, China) that was studied in a denitrifying quinoline-removal bioreactor [40]. D. hafniense (AP008230) were previously isolated from an environment contaminated with dechlorinate tetrachloroethene (PCE) [41].…”

Evaluation of the microbial diversity of denitrifying bacteria in batch reactor

“…A lot of them occur in wastewater and play an important role in the biological decontamination treatment of such sites (http://en.wikipedia.org/wiki/Rhodocyclaceae). Liu et al (2006), fed a denitrifying reactor with quinoline (40 mg/L) -a toxic amine used in the manufacture of dyes, pesticides and synthetic fuels, glucose (180 mg/L), nitrate and potassium phosphate (C/N/P of 150:30:1). The inoculum was from the second sedimentation tank of the sewage treatment system of Industry Shanghai Coking & Chemical Factory (Wujing, Shanghai -Japan).…”

“…Many inocula from domestic and industrial sewage treatment plants may contain denitrifying bacteria, mainly in activated sludge systems (Liu et al, 2006;Daniel et al, 2009), where the biological nitrogen removal occurs to promote denitrification, i.e., under heterotrophic anoxic conditions, the organic carbon sources act as electron donors and reduce nitrate to nitrogen gas (Canto et al, 2008).…”

Efficient regulation of elemental sulfur recovery through optimizing working height of upflow anaerobic sludge blanket reactor during denitrifying sulfide removal process

“…and Thauera sp. were two ubiquitous denitrifying sulfur oxidizing bacteria, which were able to covert S 2À to S 0 and simultaneous reduce NO 3 À to N 2 (Liu et al, 2006). Arcobacter sp.…”