Bioengineering of Bacterial Polymer Inclusions Catalyzing the Synthesis of <i>N</i> -Acetylneuraminic Acid
Bibliographic record
Abstract
N-Acetylneuraminic acid is produced by alkaline epimerization of N-acetylglucosamine to N-acetylmannosamine and then subsequent condensation with pyruvate catalyzed by free N-acetylneuraminic acid aldolase. The high-alkaline conditions of this process result in the degradation of reactants and products, while the purification of free enzymes to be used for the synthesis reaction is a costly process. The use of N-acetylglucosamine 2-epimerase has been seen as an alternative to the alkaline epimerization process. In this study, these two enzymes involved in N-acetylneuraminic acid production were immobilized to biopolyester beads in vivo in a one-step, cost-efficient process of production and isolation. Beads with epimerase-only, aldolase-only, and combined epimerase/aldolase activity were recombinantly produced in Escherichia coli. The enzymatic activities were 32 U, 590 U, and 2.2 U/420 U per gram dry bead weight, respectively. Individual beads could convert 18% and 77% of initial GlcNAc and ManNAc, respectively, at high substrate concentrations and near-neutral pH, demonstrating the application of this biobead technology to fine-chemical synthesis. Beads establishing the entire N-acetylneuraminic acid synthesis pathway were able to convert up to 22% of the initial N-acetylglucosamine after a 50-h reaction time into N-acetylneuraminic acid.
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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) | 0.000 | 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 | 0.001 |
| 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".