Enrichment culture
Ontology highlight
ABSTRACT:
PROVIDER: PRJDB16226 | ENA |
REPOSITORIES: ENA
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Project description:Wastewater treatment plants use a variety of bioreactor types and configurations to remove organic matter and nutrients. Little is known regarding the effects of different configurations and within-plant immigration on microbial community dynamics. Previously, we found that the structure of ammonia-oxidizing bacterial (AOB) communities in a full-scale dispersed growth activated sludge bioreactor correlated strongly with levels of NO2- entering the reactor from an upstream trickling filter (Wells et al 2009). Here, to further examine this puzzling association, we profile within-plant microbial biogeography (spatial variation) and test the hypothesis that substantial microbial immigration occurs along a transect (raw influent, trickling filter biofilm, trickling filter effluent, and activated sludge) at the same full-scale wastewater treatment plant. AOB amoA gene abundance increased >30-fold between influent and trickling filter effluent concomitant with NO2- production, indicating unexpected growth and activity of AOB within the trickling filter. Nitrosomonas europaea was the dominant AOB phylotype in trickling filter biofilm and effluent, while a distinct ‘Nitrosomonas-like’ lineage dominated in activated sludge. Prior time series indicated that this ‘Nitrosomonas-like’ lineage was dominant when NO2- levels in the trickling filter effluent (i.e., activated sludge influent) were low, while N. europaea became dominant in the activated sludge when NO2- levels were high. This is consistent with the hypothesis that NO2- production may co-occur with biofilm sloughing, releasing N. europaea from the trickling filter into the activated sludge bioreactor. Phylogenetic microarray (PhyloChip) analyses revealed significant spatial variation in taxonomic diversity, including a large excess of methanogens in the trickling filter relative to activated sludge and attenuation of Enterobacteriaceae across the transect, and demonstrated transport of a highly diverse microbial community via the trickling filter effluent to the activated sludge bioreactor. Our results provide compelling evidence that substantial immigration between coupled process units occurs and may exert significant influence over microbial community dynamics within staged bioreactors.
2015-11-03 | GSE52079 | GEO
Project description:This study explores the use of short settling times as a strategy to enhance microbial selection and prevent bulking induced by nutrient shortage in an aerobic dynamic feeding (ADF) process using mixed microbial cultures (MMCs) for polyhydroxyalkanoate (PHA) production from fermentation digestate. A 5.0-L aerobic reactor was operated under three conditions: Long Settling (LS, 30 minutes), Short Settling (SS, 10 minutes), and Short Settling under Nutrient Shortage (SS-NS, 10 minutes with reduced nutrient load). Short settling significantly improved biomass settleability, reducing the Sludge Volume Index (SVI) from 126 to 25 mL g⁻¹, and promoted the formation of dense flocs enriched in PHA-accumulating bacteria, as confirmed by transmission electron microscopy. Process kinetics revealed enhanced substrate uptake rates and improved storage yields under SS conditions, despite an elevated C/P ratio. Notably, nutrient shortage conditions were inadvertently reached by the proliferation of Polytoma mirum in the feeding tank. Although Polytoma mirum did not affect VFA composition, its presence significantly reduced nitrogen and phosphorus concentrations. These nutrient shortage conditions were maintained for at least 30 days until the system began to exhibit stress, as demonstrated by an increased SVI (178.6 mL g⁻¹). Microbial community analyses indicated marked shifts: the eukaryotic assemblage transitioned from sessile to motile ciliates under SS, while bacterial diversity within the PHA‐accumulating fraction remained high, with key taxa such as Sphaerotilus and Neomegalonema becoming more prevalent under phosphorus-limited conditions. Overall, short settling not only improved microbial selection but also prevented bulking by retaining well-aggregated biomass, thereby mitigating nutrient shortage conditions.
2025-07-24 | GSE303500 | GEO
Project description:This study explores the use of short settling times as a strategy to enhance microbial selection and prevent bulking induced by nutrient shortage in an aerobic dynamic feeding (ADF) process using mixed microbial cultures (MMCs) for polyhydroxyalkanoate (PHA) production from fermentation digestate. A 5.0-L aerobic reactor was operated under three conditions: Long Settling (LS, 30 minutes), Short Settling (SS, 10 minutes), and Short Settling under Nutrient Shortage (SS-NS, 10 minutes with reduced nutrient load). Short settling significantly improved biomass settleability, reducing the Sludge Volume Index (SVI) from 126 to 25 mL g⁻¹, and promoted the formation of dense flocs enriched in PHA-accumulating bacteria, as confirmed by transmission electron microscopy. Process kinetics revealed enhanced substrate uptake rates and improved storage yields under SS conditions, despite an elevated C/P ratio. Notably, nutrient shortage conditions were inadvertently reached by the proliferation of Polytoma mirum in the feeding tank. Although Polytoma mirum did not affect VFA composition, its presence significantly reduced nitrogen and phosphorus concentrations. These nutrient shortage conditions were maintained for at least 30 days until the system began to exhibit stress, as demonstrated by an increased SVI (178.6 mL g⁻¹). Microbial community analyses indicated marked shifts: the eukaryotic assemblage transitioned from sessile to motile ciliates under SS, while bacterial diversity within the PHA‐accumulating fraction remained high, with key taxa such as Sphaerotilus and Neomegalonema becoming more prevalent under phosphorus-limited conditions. Overall, short settling not only improved microbial selection but also prevented bulking by retaining well-aggregated biomass, thereby mitigating nutrient shortage conditions.
2025-07-24 | GSE303499 | GEO
Project description:This study explores the use of short settling times as a strategy to enhance microbial selection and prevent bulking induced by nutrient shortage in an aerobic dynamic feeding (ADF) process using mixed microbial cultures (MMCs) for polyhydroxyalkanoate (PHA) production from fermentation digestate. A 5.0-L aerobic reactor was operated under three conditions: Long Settling (LS, 30 minutes), Short Settling (SS, 10 minutes), and Short Settling under Nutrient Shortage (SS-NS, 10 minutes with reduced nutrient load). Short settling significantly improved biomass settleability, reducing the Sludge Volume Index (SVI) from 126 to 25 mL g⁻¹, and promoted the formation of dense flocs enriched in PHA-accumulating bacteria, as confirmed by transmission electron microscopy. Process kinetics revealed enhanced substrate uptake rates and improved storage yields under SS conditions, despite an elevated C/P ratio. Notably, nutrient shortage conditions were inadvertently reached by the proliferation of Polytoma mirum in the feeding tank. Although Polytoma mirum did not affect VFA composition, its presence significantly reduced nitrogen and phosphorus concentrations. These nutrient shortage conditions were maintained for at least 30 days until the system began to exhibit stress, as demonstrated by an increased SVI (178.6 mL g⁻¹). Microbial community analyses indicated marked shifts: the eukaryotic assemblage transitioned from sessile to motile ciliates under SS, while bacterial diversity within the PHA‐accumulating fraction remained high, with key taxa such as Sphaerotilus and Neomegalonema becoming more prevalent under phosphorus-limited conditions. Overall, short settling not only improved microbial selection but also prevented bulking by retaining well-aggregated biomass, thereby mitigating nutrient shortage conditions.
2025-07-24 | GSE303497 | GEO
Project description:Amplicon sequencing analysis of 16S rRNA gene of DHS reactor
| PRJDB8576 | ENA
Project description:Amplicon sequencing analysis of 16S rRNA of partial-nitrification anammox reactor
| PRJDB18291 | ENA
Project description:This study investigates the role of carbon-to-phosphorus (C/P) ratios in shaping microbial community dynamics and polyhydroxyalkanoates (PHA) production in sequencing batch reactors (SBR) fed with volatile fatty acids. Three conditions, characterized by fixed organic loading rates but varying C/P ratios (Run 1 = 170 Cmol Pmol-1; Run 2 = 235 Cmol Pmol-1; Run 3 = 400 Cmol Pmol-1;), were tested to explore their impact on PHA accumulation, biomass growth, and reactor stability. Results indicate that the moderate phosphorus limitation of Run 2 achieves the best overall performance, with a PHA volumetric productivity of 2.02 g PHA L⁻¹ d⁻¹ and process stability. Under these conditions, PHA-accumulating bacteria, primarily Sphaerotilus and Leadbetterella, dominated the microbial community, with a notable contribution from eukaryotic organisms, particularly Rhogostoma, Vorticella and Tokophrya, which appeared to regulate bacterial populations through selective predation. Conversely, higher C/P ratio increased the storage yield but lowered the productivity (1.55 gPHA L-1 h-1), compromising sludge settleability and reactor stability, indicating impaired microbial functionality. Transmission electron microscopy further confirmed the presence of intracellular PHA granules and polyphosphate reserves, reinforcing the connection between nutrient limitation and adaptive microbial strategies. Overall, these findings highlight the critical role of the C/P ratio in shaping the performance of mixed microbial cultures, demonstrating that a well-balanced nutrient supply can enhance PHA production while maintaining microbial community stability. The results contribute to optimizing the selection process for mixed microbial cultures, offering valuable insights into the impact of carbon-to-nutrient ratios in the feeding strategy.
2025-07-14 | GSE302521 | GEO
Project description:This study investigates the role of carbon-to-phosphorus (C/P) ratios in shaping microbial community dynamics and polyhydroxyalkanoates (PHA) production in sequencing batch reactors (SBR) fed with volatile fatty acids. Three conditions, characterized by fixed organic loading rates but varying C/P ratios (Run 1 = 170 Cmol Pmol-1; Run 2 = 235 Cmol Pmol-1; Run 3 = 400 Cmol Pmol-1;), were tested to explore their impact on PHA accumulation, biomass growth, and reactor stability. Results indicate that the moderate phosphorus limitation of Run 2 achieves the best overall performance, with a PHA volumetric productivity of 2.02 g PHA L⁻¹ d⁻¹ and process stability. Under these conditions, PHA-accumulating bacteria, primarily Sphaerotilus and Leadbetterella, dominated the microbial community, with a notable contribution from eukaryotic organisms, particularly Rhogostoma, Vorticella and Tokophrya, which appeared to regulate bacterial populations through selective predation. Conversely, higher C/P ratio increased the storage yield but lowered the productivity (1.55 gPHA L-1 h-1), compromising sludge settleability and reactor stability, indicating impaired microbial functionality. Transmission electron microscopy further confirmed the presence of intracellular PHA granules and polyphosphate reserves, reinforcing the connection between nutrient limitation and adaptive microbial strategies. Overall, these findings highlight the critical role of the C/P ratio in shaping the performance of mixed microbial cultures, demonstrating that a well-balanced nutrient supply can enhance PHA production while maintaining microbial community stability. The results contribute to optimizing the selection process for mixed microbial cultures, offering valuable insights into the impact of carbon-to-nutrient ratios in the feeding strategy.
2025-07-14 | GSE302520 | GEO