The Formation of Covalent Linkages in Lignocellulosic Biomass via the Oxocarbenium Intermediate
Bibliographic record
Abstract
Understanding the formation of lignin-carbohydrate complex (LCC) linkages in lignocellulosic biomass (LCB) is crucial because these interactions contribute to plant recalcitrance. Herein, a new mechanism for LCC linkage formation, based on the formation of the oxocarbenium intermediate, is explored. We applied density functional theory to monosaccharides and monolignol molecules serving as models for LCB. Mannopyranose, xylopyranose, arabinofuranose, and glucopyranuronic acid were used for hemicellulose; p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol were employed for lignin. Computations without explicit water molecules predict the stable formation of glycosidic bonds between all lignin and sugar models, with some exceptions. Including explicit water molecules showed that, for all systems, the formation of LCC bonds is more thermodynamically favorable than in the absence of water or when using implicit solvent models. The explicit solvent models indicate that hydrogen bonds involving water and organic molecules promote the formation of stable LCC bonds. Transition states and intermediates associated with oxocarbenium ions were found for mannopyranose and xylopyranose, thus evaluating the kinetics of LCC linkage formation for major components of hemicellulose. These results suggest that glycosylation reactions via the oxocarbenium intermediate can occur in plant cell walls, further providing evidence for the formation of covalent LCC linkages in LCB.
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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 | 0.000 |
| 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 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".