MICROBIAL-DEGRADATION OF PHLOROGLUCINOL AND OTHER POLYPHENOLIC COMPOUNDS

Biodegradation of phloroglucinol (1,3,5-trihydroxybenzene) and other p olyphenolic compounds by microbes may occur by aerobic and anaerobic m etabolic pathways. Aerobic microbes may initiate the mineralization of phloroglucinol or other polyphenolics by either a reductive pathway, epoxide formation, or a specific hydroxylating mechanism. Cleavage of the various intermediates of phloroglucinol and polyphenolic degradati on may occur by intradiol and extradiol mechanisms. The reductive path way in contrast to other mechanisms utilized by aerobic microbes, seem s both cumbersome and energy wasteful. The degradation of lignin and i ts associated phenolics follows an enzymatic combustion process which resembles a nonspecific enzyme-catalyzed burning. Anaerobic mineraliza tion of phloroglucinol and its associated polyphenolics by several mic robes seems to favour the reductive formation of a dihydrophloroglucin ol (1:3-dioxo-5-hydroxycyclohexane), which is cleaved by a specific hy drolase. Mineralization of numerous other polyphenolic compounds by an aerobes seems to utilize phloroglucinol as a central metabolite.