Construction and optimization of <i>trans</i>‐4‐hydroxy‐L‐proline production recombinant <i>E. coli</i> strain taking the glycerol as carbon source
Bibliographic record
Abstract
Abstract BACKGROUND Trans ‐4‐hydroxy‐L‐proline (Hyp) is a value‐added amino acid that is an applicable chiral building block in some industries, such as the pharmaceutical, cosmetic and healthcare industries. Given that glycerol is a good carbon source for microbial fermentation and a large amount of glycerol is produced by the biodiesel industry, this study investigated a value‐added Hyp fermentation from glycerol using an engineered Escherichia coli strain. RESULTS By optimizing the proline‐4‐hydroxylase ( P4H ) gene codons and vectors, a constructed recombinant Escherichia coli BL21 strain successfully converted L‐proline to Hyp. With a chemo‐physical combination mutagenesis, a high Hyp production strain that can grow with glycerol as a sole carbon source, NA45 was isolated, yielding 1.24 g L −1 from 20 g L −1 glycerol at 12 h in a 30 mL /250 mL conical flask fermentation. With further systemic optimization of nutritional elements, the output was enhanced to 1.62 g L −1 . In a 5 L fermentator, the strain achieved a surprisingly high output of 25.4 g L −1 at 48 h in fed batch mode. CONCLUSION A high Hyp production strain growing well on glycerol as carbon source was successfully engineered, which is a promising candidate for the industrial Hyp production. © 2016 Society of Chemical Industry
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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 teacher head, 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".