Mechanisms and pathways of aniline elimination from aquatic environments

Abstract

The fate of aniline, a representative of arylamine pollutants derived from the manufacture of dyes, coal liquefaction, and pesticide degradation, was comprehensively evaluated by use of unpolluted and polluted pond water as model environments. Evaporation plus autoxidation proved to be minor elimination mechanisms, removing ca. 1% of the added aniline per day. Instantaneous binding to humic components of a 0. 1 % sewage sludge inoculum removed 4%. Biodegradation of aniline in pond water was accelerated by the sewage sludge inoculum. A substantial portion of the degraded aniline carbon was mineralized to CO2 within a 1-week period, and microbial biomass was formed as a result of aniline utilization. Biodegradation was clearly the most significant removal mechanism of polluting aniline from pond water. A gas chromatographic-mass spectrometric analysis of biodegradation intermediates revealed that the major pathway of aniline biodegradation in pond water involved oxidative deamination to catechol, which was further metabolized through cis,cis-muconic, beta-ketoadipic, levulinic, and succinic acid intermediates to CO2. Minor biodegradation pathways involved reversible acylation to acetanilide and formanilide, whereas N-oxidation resulted in small amounts of oligomeric condensation products.

Relationship between properties of a series of anilines and their transformation by bacteria

“…The absence of other products from the samples, as well as the fact that aniline-grown isolates could oxidize the respective catechols (catechol, 4-chlorocatechol, 4-methylcatechol, and 3-nitrocatechol) without a lag, suggests that catechols are intermediates in the metabolism of anilines. Other re- searchers (11,15,28,31,34) have reported catechol and 4-chlorocatechol as metabolites of bacterial transformation of aniline and 3-chloroaniline. No reports on metabolites of bacterial degradation of the other five anilines were found.…”

Change in bacterial community during biodegradation of aniline

“…Biodegradation by bacteria, however, has been found to be the most significant mechanism of aniline removal from aquatic environments. Thus, Lyons et al (1984) found higher aniline biodegradation activity in polluted pond water than in unpolluted water.…”

Modeling of Nitrification Inhibition with Aniline in Suspended‐Growth Processes

“…However, these processes are much slower than biodegradation (Zissi and Lyberatos, 1999). Aromatic hydrocarbons are typically oxidized by dioxygenases to catechols, which are further cleaved (Atlas, 1997;Lyons et al, 1984;Peres et al, 1998;Pitter and Chudoba, 1990) and degraded through a tricarboxylic acid cycle to yield carbon dioxide as the end product.…”