Rapid method for extracting the antibiotic mutacin 1140 from complex fermentation medium yeast extract
Bibliographic record
Abstract
The peptide antibiotic mutacin 1140 belongs to the group of antibiotics called lantibiotics. They are ribosomally synthesized and undergo extensive enzymatic modifications before being excreted into the culture medium. By using reverse-phase-high-performance liquid chromatography (RP-HPLC) and a semiquantitative bacteriocin bioassay to track mutacin 1140, an efficient ammonium sulfate (AS) precipitation method has been developed for removing mutacin 1140 from a complex medium containing 5% yeast extract. This method minimizes the amounts of fermentation by-products and media components that make downstream purification processes more difficult and economically infeasible. The method may be adaptable for the initial purification step of other lantibiotics. A threefold decrease in the precipitation of the medium components found in yeast extract, at pH 8.0 vs. pH 2.0, may have broad utility for the isolation of secondary metabolites produced in this complex medium. The average yield of mutacin 1140 from the fermentation medium was determined as 66%.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.004 |
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".