Optimization of Citric Acid Production from a New Strain and Mutant of<i>Aspergillus niger</i>Using Solid State Fermentation
Bibliographic record
Abstract
A new strain of Aspergillus niger isolated from soil and its mutant were used for citric acid production from carob under solid-state fermentation conditions. The parental strain produced 30 g/kg citric acid, while the mutant G4, selected after four rounds of gamma ray irradiation, produced 60 g/kg. Maximum citric acid production was obtained after 7 days of incubation, as the acid production was 34 and 64 g/kg for parental and mutant strains, respectively. The addition of 2% methanol increased citric acid production from the parental strain to 42 and the mutant G4 to 65 g/kg. Trace elements, namely Cu, Fe, and Zn, promoted the production of citric acid as the acid production from the parental strain increased to 46 g/kg and for mutant G4 increased to 73 g/kg after their addition. The optimum spore inoculum concentration for acid production was 107 ml−1, and the optimum pH was 5 for both parental and mutant strains.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".