Mechanism of Alkaline Lignin Oxidation Using Laccase-methyl Syringate Mediator System
Bibliographic record
Abstract
The mechanism of alkaline lignin oxidation in presence of laccase-methyl syringate (MS) mediator is discussed in terms of morphological changes that take place during exposure of the lignin to the phosphate buffer solution (pH=6.5) for 72hr at 70oC. The SEM analysis of lignin before and after enzymatic treatment reveals the morphological changes explained by the interaction of the lignin surface groups with laccase-methyl syringate system. The BET analysis confirms that this interaction causes the change in the surface area from 2.75 to 5.50cm2/g. The corresponding pore-size distribution in lignin sample treated with laccase-methyl syringate is much broader in comparison to the untreated lignin and the pores within 25-150nm range are detected as a result of the BJH analysis. The electrochemical study of lignin, lignin with laccase, and lignin with laccase in presence of the mediator in the buffer solution has been performed in the potential range from -0.3 to +1.0V vs. Ag, AgCl, Cl- reference electrode. The cyclic voltammetry confirms reversible oxidation-reduction behavior of the methyl syringate natural mediator in anaerobic and aerobic environment. Specifically in anaerobic conditions three oxidation anodic peaks (0.265V, 0.474V and 0.884V) and two reduction peaks (0.421V and 0.103V) were detected out of which the oxidation peak at 0.474V was assigned to the formation of MS∙ radical. In aerobic conditions the methyl syringate demonstrates two oxidation peaks (0.473V and 0.812V) and two reduction peaks (0.410V and 0.135V). The mechanism of MS radical stability in oxygen vs. anaerobic environment is proposed based on formation of MS∙ radicals.
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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 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".