Lab-scale sequencing batch reactors of AS under antibiotic selection pressure
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA694732 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Sequencing batch reactors for nitrification and denitrification Metagenome
| PRJNA513916 | ENA
Project description:Oxygen-limited autotrophic nitrification/denitrification (OLAND) is a one-stage combination of partial nitritation and anammox, which can have a challenging process start-up. In this study, start-up strategies were tested for sequencing batch reactors (SBR), varying hydraulic parameters, i.e. volumetric exchange ratio (VER) and feeding regime, and salinity. Two sequential tests with two parallel SBR were performed, and stable removal rates > 0.4 g N l(-1) day(-1) with minimal nitrite and nitrate accumulation were considered a successful start-up. SBR A and B were operated at 50% VER with 3 g NaCl l(-1) in the influent, and the influent was fed over 8% and 82% of the cycle time respectively. SBR B started up in 24 days, but SBR A achieved no start-up in 39 days. SBR C and D were fed over 65% of the cycle time at 25% VER, and salt was added only to the influent of SBR D (5 g NaCl l(-1)). Start-up of both SBR C and D was successful in 9 and 32 days respectively. Reactor D developed a higher proportion of small aggregates (0.10-0.25 mm), with a high nitritation to anammox rate ratio, likely the cause of the observed nitrite accumulation. The latter was overcome by temporarily including an anoxic period at the end of the reaction phase. All systems achieved granulation and similar biomass-specific nitrogen removal rates (141-220 mg N g(-1) VSS day(-1)). FISH revealed a close juxtapositioning of aerobic and anoxic ammonium-oxidizing bacteria (AerAOB and AnAOB), also in small aggregates. DGGE showed that AerAOB communities had a lower evenness than Planctomycetes communities. A higher richness of the latter seemed to be correlated with better reactor performance. Overall, the fast start-up of SBR B, C and D suggests that stable hydraulic conditions are beneficial for OLAND while increased salinity at the tested levels is not needed for good reactor performance.
| S-EPMC3821683 | biostudies-literature
Project description:Metaviromes from batch mesophilic anaerobic digestion reactors, raw sequence reads
| PRJNA1134235 | ENA
Project description:Bacterial Communities in Lab-Scale Batch Anaerobic Digester Treating Wheat Straw
| PRJEB15600 | ENA
Project description:The use of wildflower species as biogas feedstock carries the risk that their seeds survive anaerobic digestion (AD) and cause weed problems if spread with the digestate. Risk factors for seed survival in AD include low temperature, short exposure and hardseededness (HS). However, it is not possible to predict how AD will affect seed viability of previously unstudied species. In laboratory-scale reactors, we exposed seeds of eight species from a mixture of flowering wild plants intended as biogas feedstock and three reference species to AD at two mesophilic temperatures. Half of the species were HS, the other was non-HS (NHS). Viability was determined using a combination of tetrazolium and germination tests. Viability and germinability were modeled as functions of exposure time using a dose-response approach. Responses to AD varied considerably among species, and none of the considered influencing factors (time, temperature, HS) had a consistent effect. Seed lots of a species differed in inactivation times and seed-killing efficacy. The HS species Melilotus officinalis, Melilotus albus, and Malva sylvestris were particularly AD-resistant. They were the only ones that exhibited biphasic viability curves and tended to survive and germinate more at 42°C than at 35°C. Viability of the remaining species declined in a sigmoidal curve. Most NHS species were inactivated within a few days (Cichorium intybus, Daucus carota, Echium vulgare, and Verbascum thapsus), while HS species survived longer (Malva alcea). AD stimulated germination in the HS species A. theophrasti and its AD-resistance overlapped with that of the most resistant NHS species, C. album and tomato. In all seed lots, germinability was lost faster than viability, implying that mainly dormant seeds survived. After the maximum exposure time of 36 days, seeds of HS species and Chenopodium album were still viable. We concluded that viability responses to mesophilic AD were determined by the interplay of AD-conditions and species- and seed-lot-specific traits, of which HS was an important but only one factor. For the use of wildflowers as biogas feedstock, we recommended long retention times and special care with regard to HS species.
| S-EPMC9337220 | biostudies-literature
Project description:Biofilms are ubiquitous in nature, forming diverse adherent microbial communities that perform a plethora of functions. Here, we operated two laboratory-scale sequence batch reactors enriched with Candidatus Accumulibacter phosphatis (Accumulibacter) performing enhanced biological phosphorus removal (EBPR). Reactors formed two distinct biofilms, a floccular biofilm, consisting of small, loose, microbial aggregates, and a granular biofilm, forming larger, dense, spherical aggregates. Using metaproteomic methods we investigated the proteomic differences between these two biofilm communities, identifying a total of 2022 unique proteins. Both biofilms contained proteins that were indicative of core EBPR metabolisms and cellular function. To understand the proteomic differences between floccular and granular biofilm communities, we compared protein abundances that were statistically enriched in both biofilm states (alpha level = 0.05). Floccular biofilms were enriched with pathogenic secretion systems suggesting a previously unrecognized, highly competitive, mixed microbial community. Comparatively, granular biofilms revealed a high stress environment with evidence of nutrient starvation, phage predation pressure, extracellular polymeric substance (EPS) synthesis, and increased cell lysis. Granular biofilms enriched outermembrane transport proteins to scavenge the extracellular milieu for amino acids and other metabolites, likely released through cell lysis, to supplement core EBPR metabolic pathways. This study provides the first detailed proteomic comparison between Accumulibacter–enriched floccular and granular biofilm communities, proposes a conceptual model for the granule biofilm, and offers novel insights into granule biofilm formation and stability.
2015-08-24 | PXD002404 | Pride