Lignin degradation process

However, in the light of the results presented herein, this cannot be stated unequivocally, otherwise it would follow that only guaiacyl type compounds would be obtained as softwood lignin degradation products. It has been found that the native lignin from the softwood white Scots pine also yields p-hydroxybenzaldehyde upon oxidation. Thus, it seems that either coniferyl alcohol is not the only lignin progenitor in woody tissues, or that this coniferyl compound is preceded in the process of... 

Table X. Activation Energy of the Degradation Process of Selected Lignin Sulfonates as well as their Derivatives with Terephthaloyl Chloride...

Figure 2.3. Hypothetical mechanism of ligninocellulose transformation by enzymes of white-rot fungi. The initial products of partial wood hydrolysis distinctly induce enzymatic systems accelerating the degradation processes. Reprinted from Leonowicz, A., Cho, N.-S., Luterek, I, et al. (2001). Fungal laccase properties and activity on lignin./. Basic Microbiol. 41,185-227, with permission from Wiley-VCH.

The main advantage of enzymatic posthydrolysis over the acidic process is the milder operation, which leads to reaction medium free of sugar-or lignin-degradation compounds that can limit microbial performance. Conversely, the acid process is faster, and the catalyst is cheap and allows high monosaccharide recovery. To make a correct choice, the performance of the raw material under consideration must be studied for each process. 

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