Decarboxylation phthalate degradation

It has become clear that benzoate occupies a central position in the anaerobic degradation of both phenols and alkylated arenes such as toluene and xylenes, and that carboxylation, hydroxylation, and reductive dehydroxylation are important reactions for phenols that are discussed in Part 4 of this chapter. The simplest examples include alkylated benzenes, products from the carboxylation of napthalene and phenanthrene (Zhang and Young 1997), the decarboxylation of o-, m-, and p-phthalate under denitrifying conditions (Nozawa and Maruyama 1988), and the metabolism of phenols and anilines by carboxylation. Further illustrative examples include the following ... 

Carboxyl groups in the conversion of benzoate to catechol (Neidle et al. 1991), and during the degradation of 4-methyl-o-phthalate by P. fluorescens strain JT701 that takes place by analogous oxidative decarboxylation with the formation of 4-methyl-2,3-dihydroxyben-zoate (Ribbons et al. 1984). 

Decarboxylation is an integral part of the pathway for degradation of o-phthalate—under both aerobic and denitrifying conditions (Section 6.7.3.1). The degradation of o-phthalate by P. fluorescens PHK takes place by initial dioxygenation and dehydrogenation to 4,5-dihydroxyphthalate followed by decarboxylation to 3,4-dihydroxybenzoate (Pujar and Ribbons... 

The degradation of naphthalene-2-carboxylate by Burkholderia sp. strain JT 1500 involves formation of naphthalene-l-hydroxy-2-car-boxylate rather than initial oxidative decarboxylation. Naphtha-lene-l,2-dihydrodiol-2-carboxylate is not involved, so that possibly the reaction is carried out by a monooxygenase. Subsequent reactions produce pyruvate and o-phthalate that is degraded via 4,5-dihydroxyphthalate (Morawski et al. 1997) this has already been noted. Degradation of naphthalene carboxylates formed by oxidation of methyl groups was noted above. 

The degradation of o-, m-, and p-phthalates under denitrifying conditions has been examined (Nozawa and Maruyama 1988), and after an initial decarboxylation to benzoate followed the pathway for the anaerobic degradation of benzoate that has been noted above formation of the CoA ester, reduction to cyclohex-l-ene carboxylate, hydroxylation to 2-hydroxycyclohexane car-boxylate, and ring fission to pimelic acid that was further degraded by P-oxi-dation. 

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