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Genome-resolved metatranscriptomics unveils distinct microbial functionalities across aggregate sizes in aerobic
A Y A Mohamed1, Laurence Gill1, Alejandro Monleon1
1Department of Civil, Structural & Environmental Engineering, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland.
Environmental Science and Ecotechnology
|April 16, 2025
Summary
Microbial activity in aerobic granular sludge (AGS) varies by aggregate size. Polyphosphate-accumulating organisms (PAOs) like Accumulibacter dominate larger granules, while Phosphoribacter are active in smaller flocs, impacting wastewater treatment.
Area of Science:
- Environmental microbiology
- Wastewater treatment technologies
- Metagenomics and metatranscriptomics
Background:
- Aerobic granular sludge (AGS) systems utilize microbial aggregates for efficient wastewater treatment.
- Distinct microbial community compositions exist within different aggregate sizes in AGS.
- Limited research has compared the specific microbial activities across varying aggregate sizes in AGS.
Purpose of the Study:
- To investigate microbial activity patterns within differently sized aggregates in a full-scale AGS plant.
- To understand the relationship between microbial abundance and metabolic activity in AGS.
- To identify the functional roles of microbial communities in relation to aggregate size.
Main Methods:
- Genome-resolved metatranscriptomics was employed to analyze microbial activity.
- Analysis of microbial activity patterns within flocculent sludge (<0.2 mm), small granules (0.2-1.0 mm), and large granules (>1.0 mm).
- Differential gene expression analysis to compare key metabolic pathways across aggregate sizes.
Main Results:
- Microbial abundance showed a weak correlation with transcriptomic activity.
- Flocculent sludge (FL) had active nitrifiers and fermentative polyphosphate-accumulating organisms (PAOs) from *Candidatus* Phosphoribacter.
- Small and large granules (SG & LG) showed more active PAOs affiliated with *Ca.* Accumulibacter, with higher phosphorus uptake gene expression.
Conclusions:
- Aggregate size significantly influences the metabolic activity and functional roles of microbial communities in AGS.
- Distinct microbial populations, particularly PAOs, exhibit size-dependent activity patterns.
- Findings provide insights for optimizing AGS performance in wastewater treatment.
Keywords:
Aerobic granular sludgeDifferential expression analysisGenome-resolved metatranscriptomicsMicrobial activityWastewater treatmentMore Related Videos
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