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Biological and chemical mineralization of pyridine

Journal Article · · Environmental Toxicology and Chemistry; (United States)
; ;  [1]
  1. Pennsylvania State Univ., University Park, PA (United States). Lab. of Soil Biochemistry

A comparison was made between biological and chemical mineralization of pyridine, an N-heterocyclic pollutant, in a liquid culture and a slurry of ground water and subsurface sediment. A bacterial culture of an Alcaligenes sp. that degrades pyridine was found to be more effective at oxidizing [2,6-[sup 14]C] pyridine to [sup 14]CO[sub 2] than Fenton's reagent. Alcaligenes sp. converted 73.1 % of the [sup 14]C-labeled pyridine to [sup 14]CO[sub 2], whereas the Fenton reagent converted 65.6% of the compound. In the case of bacteria, the remaining chemical was incorporated primarily into biomass (9.2%), whereas the remaining pyridine was converted to unidentified products (16.3%) by the Fenton reagent. However, based on chromatographic analysis, these compounds were not mono-hydroxylated pyridines. Mineralization of pyridine by Fenton's reagent was affected by the concentration of H[sub 2]O[sub 2] and by the concentration and oxidation state of available iron. Maximal mineralization occurred at a concentration of more than 0.15% H[sub 2]O[sub 2] (44 mM), 1 mM Fe[sup 3+], or 2 mM Fe[sup 2+]. Furthermore, the rates of both microbial and chemical mineralization were influenced by the initial pyridine concentration. Maximum specific rates of mineralization were 6.5 [mu]g/h/mg biomass for the bacteria and 2.7 [mu]g/h/mg Fe[sup 2+] for the Fenton reagent. The feasibility of using Fenton's reagent for treating ground water and subsurface sediments polluted with pyridine was found to be limited, because only 24.5% of the pyridine was converted in CO[sub 2]. In contrast, when cultures of the Alcaligenes sp. were used to treat ground water, as much as 54.4% of the labeled compound was mineralized to [sup 14]CO[sub 2].

OSTI ID:
5431129
Journal Information:
Environmental Toxicology and Chemistry; (United States), Journal Name: Environmental Toxicology and Chemistry; (United States) Vol. 13:1; ISSN 0730-7268; ISSN ETOCDK
Country of Publication:
United States
Language:
English