Showing papers by "Juliana Calábria de Araújo published in 2015"
TL;DR: Different molecular techniques are described, the questions that can be addressed by each technique, enumerate their limitations and give practical advices for their use are given.
Abstract: Anaerobic digestion is used with success for the treatment of solid waste, urban and industrial effluents with a concomitant energy production. The process is robust and stable, but the complexity of the microbial community involved in the process is not yet fully comprehensive. Nowadays, the study of this complex ecosystem is facilitated by the availability of different molecular tools, but it is very important to choose the adequate tool to answer specific questions. The aim of this review is to describe different molecular techniques, indicate the questions that can be addressed by each technique, enumerate their limitations and give practical advices for their use. Examples of how the molecular tools have been used to address various questions in anaerobic digestion are presented. The key point now is to apply all this information to improve anaerobic digestion. The integration of concepts of microbial-ecology, environmental-engineering, modeling and bioinformatics is currently necessary.
55 citations
TL;DR: Results indicated that sulphide concentrations of 1–6 mg L−1 could be efficiently removed from the effluent of a pilot-scale UASB reactor in two sulphide biological oxidation reactors at HRTs of 12 and 24 h, showing the potential for sulphur recovery from anaerobically treated domestic wastewater.
Abstract: We developed a biological sulphide oxidation system and evaluated two reactors (shaped similar to the settler compartment of an up-flow anaerobic sludge blanket [UASB] reactor) with different support materials for biomass retention: polypropylene rings and polyurethane foam. The start-up reaction was achieved using microorganisms naturally occurring on the open surface of UASB reactors treating domestic wastewater. Sulphide removal efficiencies of 65% and 90% were achieved with hydraulic retention times (HRTs) of 24 and 12 h, respectively, in both reactors. However, a higher amount of elemental sulphur was formed and accumulated in the biomass from reactor 1 (20 mg S0 g−1 VTS) than in that from reactor 2 (2.9 mg S0 g−1 VTS) with an HRT of 24 h. Denaturing gradient gel electrophoresis (DGGE) results revealed that the the pink and green biomass that developed in both reactors comprised a diverse bacterial community and had sequences related to phototrophic green and purple-sulphur bacteria such as Chlorobiu...
17 citations
TL;DR: The results suggest that different metabolic pathways were involved in ammonium removal in the post-UASB reactor sponge-based, suggesting that denitrifier, nitrifiers, and anammox bacteria coexisted in the reactor.
17 citations
TL;DR: Results showed that the inoculum type and cultivation conditions were properly suited for methanotrophic enrichment, and the presence and high predominance of Verrucomicrobia in the enriched biomass suggested that other unknown methanOTrophic species related to that phylum might also have occurred in the reactor.
Abstract: In this study, methanotrophic microorganisms were enriched from a municipal wastewater sludge taken from an Upflow Anaerobic Sludge Blanket reactor. The enrichment was performed in a sequencing batch reactor (SBR) with an autotrophic medium containing nitrite and nitrate. The microbial community composition of the inoculum and of the enrichment culture after 100 days of SBR operation was investigated and compared with the help of data obtained from 454 pyrosequencing analyses. The nitrite and nitrate removal efficiencies were 68% and 53%, respectively, probably due to heterotrophic denitrification. Archaeal cells of the anaerobic methanotrophic Archaic (ANME)-I and ANME-II groups were detected by polymerase chain reaction throughout the whole cultivation period. Pyrosequencing analysis showed that community composition was different among the two samples analysed. The dominant phyla found in the inoculum were Synergistestes, Firmicutes and Euryarchaeota, while Planctomycetes, Verrucomicrobia, Chloroflexi ...
15 citations