Lignin humus

Thus, based on material applications, the following polymers are important natural rubber, coal, asphaltenes (bitumens), cellulose, chitin, starch, lignin, humus, shellac, amber, and certain proteins. Figure 4 shows the primary structures of some of the above polymers. For detailed information on their occurrence, conventional utilization, etc., refer to the references cited previously. 

Among other organic components lignin, humus acids, surfactants, tannins, pectins, etc. are present at lower concentrations. 

The interesting aspect of one of these examples (Figure 3.20) is the inclusion of carbon dioxide within the cycle. Both postulates recognize the production of carbon dioxide from coal, thereby pointing out the relationship of carbon dioxide and coal but recognition of carbon dioxide as part of the natural cycle between plants, lignin, humus, and coal underscores the closeness of the relationship and the end product of the environmental aspects of coal use. 

Biopolymers Lignin, humus Cellulose, starch, chitin, pullulan, zein... 

Kogel, I. (1986). Estimation and decomposition pattern of the lignin component in forest humus layers. Soil Biology and Biochemistry 18 589-594. 

Kogel, I. and Bochter, R. (1985). Characterization of lignin in forest humus layers by high-performance liquid chromatography of cupric oxide oxidation products. Soil Biology and Biochemistry 17 637-640. 

Carbohydrates and proteins serve as an energy source for microorganisms or as materials for forming their body substances while lignin and other phenolic compounds decompose more slowly than the two other main constituents. Therefore, lignin and other phenolic compounds may be regarded as materials essential for forming the dark colored substances in humus. 

Waksman, S. A., and Iyer, K. R. N. (1933). Contribution to our knowledge of the chemical nature and origin of humus IV. Fixation of proteins by lignins and formation of complexes resistant to microbial decomposition. Soil Sci. 36, 69-82. 

Figure 2.5. Schematic representation of the modified lignin theory of humus formation. Adapted with permission from Stevenson, F. J. (1994). Humus Chemistry Genesis, Composition, Reactions, 2nd ed. John Wiley and Sons, New York.

Martin, J. R, and Haider, K. (1980). Microbial degradation and stabilization of 14C-labeled lignins, phenols, and phenolic polymers in relation to soil humus formation In Lignin Biodegradation Microbiology Chemistry and Potential Applications, Vol. II. Kent-Kirk, T., Higuchi, T., and Chang, H., eds., CRC Press, Boca Raton, FL, pp. 77-100. 

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