Sodium Amalgam Reductive Degradation of Fungal and Model Phenolic Polymers, Soil Humic Acids, and Simple Phenolic Compounds

Reductive degradation of fungal humic acid‐type compounds and model phenolase phenolic polymers with 5% Na‐amalgam under N 2 yielded 4 to 32% simple phenols which could be separated by two‐dimensional thin‐layer chromatography. Yields from soil and peat humic acids were 3 to 6%. Phenols recovered from all three types of polymers in greatest concentration were resorcinol, orcinol, 2,6‐dihydroxytoluene, phloroglucinol, p ‐cresol or m ‐cresol and p ‐hydroxybenzoic, p ‐hydroxycinnamic, ferulic, vanillic, 3,5‐dihydroxybenzoic, and protocatechuic acids. Vanillic and ferulic acids were found in the fungal polymers only when the organisms were cultured on plant residues or the phenols were placed under the fungus pads. Many other phenols incorporated into the model polymers were recovered in relatively low concentrations or not at all. In general, the phenols recovered in greatest concentrations from the polymers were those least affected by the Na‐amalgam reaction. Some of the hydroxybenzoic acids were partially or completely decarboxylated to form the corresponding phenols. Less than half the reacted phloroglucinol, caffeic acid and several other phenols were recovered. Hydroxynaphthalenic compounds were destroyed by the reaction. N‐linked phenylglycine was not recovered by the procedure. Over 16 phenols separated upon Na‐amalgam reduction of the soil humic acid fraction after incubation with 14 C glucose or wheat straw were radioactive.