Degradation of phenolic compounds

Phenol is an important intermediate in the anaerobic degradation of many complex and simple aromatic compounds. Tschech and Fuchs proposed that the carboxylation of phenol to 4-hydroxybenzoate is the first step in the degradation of phenol under denitrifying conditions. However, 4-hydroxybenzoate is not detected in the cultures or cell extracts of the denitrifying Pseudomonas species in the presence of CO2 and phenol, but it is detected if phenol is replaced by phenolphosphate. In contrast, 4-hydroxybenzoate is readily detected as an intermediate of phenol degradation in the iron-reducing bacterium GS-15, and 4-hydroxybenzoate may prove to be a common intermediate in the anaerobic transformation. Thus, in anaerobic degradation of phenolic compounds, it has been postulated that carboxylation reactions may play important roles. 

The degradation of phenolic compounds by fungi may involve rather unusual features of which the following three are given as illustration ... 

Chapman, P.J., An outline of reaction sequences used for the bacterial degradation of phenolic compounds, in Degradation of Synthetic Organic Molecules in the Biosphere, National Academy of Sciences, Washington, 1972, pp. 17-53. 

Healy and Young (58) observed that the conversion of vanillic and ferulic acids under anaerobic conditions to methane and CO2 was nearly stoichiometric. More than half of the organic carbon could potentially be converted to methane. This could have great importance in studies where the degradation of phenolic compounds are studied by trapping the evolved CO2. Under anaerobic conditions, part of the normal CO2 evolution may be shifted to methane production with a subsequent low reporting of CO2 evolved, and an underestimation of microbial activity in the soil (51). 

Fedorak PM, Roberts DJ, Drudey SE. 1986. The effects of cyanide on themethanogenic degradation of phenolic compounds. Water Res 20(10) 1315-1320. 

Richheimer, S.L., Bailey, D.T., Bernart, M.W., Kent, M., Viniski, J.V. and Anderson, L.D. 1999. Antioxidant activity and oxidative degradation of phenolic compounds isolated from rosemary. Rec. Res. Develop. Oil. Chem. 3 45 18... 

Fig. 4. Degradation of phenolic compounds under denitrifying conditions.

Considerable attention has been directed to the degradation of phenolic compounds. 

Schink B, Philipp B, Muller J (2000) Anaerobic degradation of phenolic compounds. Naturwissenschaften 87, 12-23. 

Chea V, Paolucci-Jeanjean D, Belleville M-P, and Sanehez J. Optimization and eharacterization of an enzymatie membrane for the degradation of phenolic compounds. Catal. Today 2012 193 49-56. 

The Fenton system (see section 9.3.2.3) is ideal for degradation of phenolic compounds to non-toxic products [333], reactions being summarised in Figure 9.15. 

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