Metabolism of 4-Chloronitrobenzene by the Yeast Rhodosporidium sp

Abstract

The yeast Rhodosporidium sp. metabolized 4-chloronitrobenzene by a reductive pathway to give 4-chloroacetanilide and 4-chloro-2-hydroxyacetanilide as the major final metabolites. The intermediate production of 4-chloronitrosobenzene, 4-chlorophenylhydroxylamine, and 4-chloroaniline was demonstrated by high-pressure liquid chromatography. Additional studies with selected metabolites established that the metabolite 4-chloro-2-hydroxyacetanilide was produced by an initial Bamberger rearrangement of the hydroxylamine metabolite, followed by acetylation. Direct C hydroxylation of the aromatic ring was not observed in this species. No hydroxamic acid production was detected, even though significant concentrations of the nitroso and hydroxylamine precursors to this functional group were observed.

Degradation of Chloronitrobenzenes by a Coculture of Pseudomonas putida and a Rhodococcus sp

“…On the other hand, a mixture of ortho-and para-aminophenolic compound and aminoaromatic compound were detected as intermediates in the metabolism of 4-CNB by Rhodosporidium sp. (4). In this case, 4-chlorohydroxylaminobenzene partially reduced from 4-CNB is converted to 5-chloro-2-aminophenol, 4-hydroxylaniline, and 4-chloroaniline, which implies that Rhodosporidium sp.…”

“…NB was added intermittently after depletion to obtain biomass due to its toxic effect on microbial growth. When necessary, NB-degrading microorganisms were cultured in the minimal salts medium supplemented with 10 mM succinate and 4 mM NH 4 Cl. Chlorohydroxyacetanilide-degrading microorganisms were cultured in chloride-free minimal salts medium containing 1 mM chlorobenzene and 0.2 mM 5-chloro-2-hydroxyacetanilide.…”

Characterization of hydroxylaminobenzene mutase from pNBZ139 cloned from Pseudomonas pseudoalcaligenes JS45

“…5.4.99.6), which converts chorismate to isochorismate in the biosynthesis of enterobactin and menaquinone, has been purified and characterized from different organisms [26–30]. As more biological hydroxymutase reactions become known [6–10,17–21,31], it may be necessary to designate a new subsubclass (5.4.4.‐) of ‘transferring hydroxy groups’ after the three current subclasses for transferring acyl, phospho, and amino groups under the intramolecular transferase (mutase) heading [25].…”

“…In the latter pathway, ammonia is released from a hydroxylamino intermediate to form the corresponding catechol. During degradation of nitrobenzene [6], chloronitrobenzene [7,8], 3‐nitrophenol [9], and 4‐nitrotoluene [10] by some bacteria, the hydroxylamino intermediates undergo an enzyme‐catalyzed rearrangement to the corresponding ortho ‐aminophenols (Fig. 1).…”

“…In its simplest form, the reaction is carried out in aqueous sulfuric acid and yields 4‐aminophenol as the major product [15]. The interest in the Bamberger rearrangement is due to the fact that such reactions are observed not only in the reduction of nitroaromatic compounds, but also in the oxidation of aromatic amines and a number of biologically important processes [8,16–19]. Although the biological conversion of hydroxylamino compounds has also been referred to as Bamberger or Bamberger‐like rearrangement, ortho ‐aminophenolic compounds are the predominant products, in contrast with the non enzymatic acid‐catalyzed reactions.…”