Biodegradation of 4-Nitrophenol in a Two-Phase System Operating with Polymers as the Partitioning Phase
Bibliographic record
Abstract
The present study has demonstrated the enhanced performance of a two-phase bioreactor, operating with polymers as a partitioning phase, as an alternative to both single phase biotreatment and to the use of an immiscible organic solvent partitioning phase, to deliver a toxic substrate (4-nitrophenol, or 4NP) to a microbial consortium in batch and repeated batch mode. Three commercial polymers were tested, Hytrel, Tone, and Elvax, and were shown to have superior properties related to the use of a consortium, including complete biocompatibility with the biomass and nonbiodegradability. Repeated kinetic tests performed with short reaction times demonstrated the accumulation of 4NP within the polymers in the range of 6-8 mg/g polymer, which reduced polymer performance in subsequent batch operations. Hytrel gave the best performance with residuals of up to 4 mg/g polymer showing no reduction in subsequent use, while for the other polymers a 4NP value lower than 2 mg/g polymer was required to have acceptable performance during repeated polymer use. Polymer reuse without affecting the process efficiency was confirmed with regeneration tests. A conventional methanol extraction method, as well as biological regeneration of the polymers by prolonged contact with the biomass, were assessed for their ability to remove the residual 4NP. Parallel kinetic tests performed with newand regenerated polymers showed a complete overlap of the 4NP concentration profiles indicating that a simple biological regeneration method provides a means of completely restoring polymer performance for repeated batch operation.
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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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".