Mechanochemical Amorphization of α-Chitin and Conversion into Oligomers of <i>N</i>-Acetyl-<scp>d</scp>-glucosamine
Bibliographic record
Abstract
Mechanochemical treatment offers great potential for environmentally sustainable processing of chitin within the context of biomass valorization. Using powder X-ray diffraction, we show that crystallinity can be reduced by 50% in 2 h in a controlled way using a ball mill. We correlate this crystallinity reduction with a decrease in interchain hydrogen bonding using infrared spectroscopy as a structural probe. Furthermore, our quantitative interpretation of the spectra reveal a decrease in glycosidic linkage content and retention of N -acetyl groups. The addition of a natural clay, kaolinite, in the ball mill leads to a significant increase in the solubility of the milled materials (up to 75.8% water-soluble products in 6 h, cf. 35.0% without kaolinite). The products of this process were characterized as oligomers of N -acetyl- d -glucosamine (chitin oligomers) with degrees of polymerization (DP) between 1 and 5 using a new quantitative matrix-assisted laser desorption-ionization (MALDI-ToF) mass spectrometric method. These data were complemented by a colorimetric assay of reducing ends and size-exclusion chromatography (SEC). N -Acetyl- d -glucosamine (the monomer) and N,N ′-diacetylchitobiose (the dimer) were obtained in yields of 5.1 and 3.9 wt %, respectively, within 6 h, which is comparable with yields of glucose and cellobiose from cellulose ball milling.
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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) | 0.001 | 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".