Culture conditions for the production of an acidic exopolysaccharide by the nitrogen-fixing bacterium <i>Burkholderia tropica</i>
Bibliographic record
Abstract
The endophytic diazotrophic bacterium Burkholderia tropica, strain Ppe8, produced copious amounts of exopolysaccharide (EPS) on batch growth in liquid synthetic media containing mannitol and glutamate as carbon and nitrogen sources. The effect of various aeration regimes and carbon source concentrations on EPS production was determined, as well as the effects of temperature and time of growth. The degree of aeration had a great influence on the yield of EPS, in contrast with the C:N ratio of the medium. Growth temperature also affected the EPS yield after the first 24 h of culture but seemed to be irrelevant after that. After isolation and purification, the EPS was analyzed by high-performance size exclusion chromatography and multiangle laser light scattering (HPSEC-MALLS), revealing a molecular mass of 300 kDa. The acid hydrolyzate of EPS was examined by HPLC and found to contain Glc, Rha, GlcA, and an aldobiouronic acid. The latter was found to have a GlcA and a Rha unit. Carboxy-reduced EPS contained Glc and Rha (3:2). The monosaccharide composition of the native acidic EPS was calculated as GlcA, Glc, and Rha in a molar ratio of 1:2:2.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.001 | 0.001 |
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".