Cryopreservation of Chlorella vulgaris Using Different Cryoprotectant Agents
Bibliographic record
Abstract
The objective of this study is to evaluate the cryopreservation of Chlorella vulgaris using different substances. The C. vulgaris was cultured in medium MH, the microalgae were grown under a 12:12 h light: dark photoperiod, illumination with 40 W led lamps, and a controlled temperature of 28±1 ºC. C.vulgaris was cultured for 15 days and the culture was aliquoted into 3-mL cryogenic tubes. The 3-mL aliquot was centrifuged, the supernatant was discarded, and the pellet was resuspended in different cryoprotectant solutions, T1-PVS1, T2-PVS2, T3-PVS2 (1% phloroglucinol), T4 (2 M glycerol), and T5 (5% methanol). The samples were rapidly frozen in liquid nitrogen (-196 °C) and analyzed after 15, 150, and 300 days of freezing. Cell viability was determined in cultures grown for 20 days. The only effective treatment was T5, which promoted the growth of thawed cultures in both solid and liquid media. After 15 days of freezing in liquid nitrogen and 20 days of culture growth, the number of viable and nonviable cells was 3.42±0.72 × 107 and 0.06±0.009 × 107, respectively, and viability was 98.2%. Similar values were obtained after 150 and 300 days of freezing: 2.17±0.15 × 107 and 2.35±0.18 × 107 viable cells, 0.05±0.02 × 107 and 0.10±0.02 × 107 nonviable cells, and viability of 97.6% and 95.8%, respectively. The cryopreservation protocol for microalgae C. vulgaris using 5% methanol was effective; therefore, it is possible to maintain this strain under axenic conditions in liquid nitrogen for long periods.
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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) | 0.000 | 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 | 0.000 |
| 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".