Using nitrogen limitation to induce polyphosphate metabolism in engineered bioreactors
Bibliographic record
Abstract
Efforts to study enhanced biological phosphorus removal (EBPR) can be hampered by the initial start-up of the culture. A nitrogen limitation was used to select for polyphosphate-accumulating organisms (PAOs) in a mixed culture that did not previously exhibit EBPR characteristics or storage product accumulation. During nitrogen-limiting conditions, accumulation of polyhydroxyalkanoate (PHA) and carbohydrate (CH) was observed, and then the characteristics of polyphosphate metabolism were observed. When the anaerobic–aerobic reactor was operated with an influent COD/N ratio of 25, the PHA and glycogen content increased quickly. During this period, PHA ranged from 13% to 30%, and CH ranged from 10% to 18%, and after 12 d anaerobic P release was observed. Polyphosphate metabolism persisted even after the nitrogen limitation was removed. Storage product accumulation may have contributed to lower effluent total suspended solids (TSS), but it had virtually no effect on sludge volume index (SVI) or capillary suction time (CST). Key words: enhanced biological phosphorus removal, microbial storage products, nutrient limitation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".