Growth kinetics of the 4‐nitrophenol degrading strain Pseudomonas putida PNP1

Abstract

A Cnitrophenol degrading strain PNPl isolated from the El-Harrach River near Algiers (Algeria) was studied with respect to its growth behaviour. According to the morphological and biochemical characteristics this strain was assigned to Pseudomom putiah. Besides 4-nitrophenol, the strain also used 1.2-and 1,4-dihydroxybenzene, benzoate, 4-hydroxybenzoate and 3&dihydroxybenmate as sources of carbon and energy, degrading them exclusively via the ortho pathway. Pseudomom putidn PNPl degrades 4-nitrophenol through a purely oxidative pathway with release of the nitro group as nitrite. During cultivation with 4-nitrophenol in ammonium-containing mineral medium. the strain PNPl grew optimally at pH 7 and at a temperature between 30 and 35 "C and showed stoichiometric nitrite release (at pH 7 and 30 "C MONOD model parameters hax = 0.615 h -1 and Ks = 0.145 mg/l). A phenomenological model for the description of growth inhibition at high 4-nitrophenol concentrations was derived (below 400 mg/l only weak inhibition and at 600 mg/l acute toxicity). In ammonium-free medium, the maximum specific growth rate was reduced to 0.318 h -1 and part of the 4-nitrophenol-N was used as the nitrogen source (32% N in biomass and 68% N in nitrite). The yield coefficients of strain PNPl were smaller in ammonium-free than in ammoniumcontaining medium (e.g. with 4-nitrophenol Y x /~ = 0.305 glg compared to 0.350 &), which can be explained by the energy expense for the assimilatory nitrite reduction in the biosynthesis of N-containing cellular compounds. But the oxygen consumption was only slightly influenced by the ammonium content of the cultivation medium (e.g. with 4-nitrophenol Y m = 1.005 g/g compared to 0.954 g/g). IntroducionNitroaromatic compounds are widely distributed substances in the chemistry and processing industries as they are of great importance in the production of synthetic dyes, pesticides, pharmaceutical raw materials and photochemicals [ 11. Because of their high mutagenic and cancerogenic potential, nitroaromatic substances pose a dan-

Bacterial Community Structure and Physiological State within an Industrial Phenol Bioremediation System

“…However, no correlation was recorded for the pseudomonads (a major constituent of the ␥-Proteobacteria). This observation was unexpected, since pseudomonads are well characterized in their ability to degrade environmental phenol contamination, and the genetics of phenol degradation has been described by a variety of strains (1,5,7,8,18,23,34,39). However, the lack of correlation we observed in situ between phenolics and pseudomonad physiological status may not be unexpected, since culture isolation conditions for bioremediation organisms are highly selective (11,42) and the catabolic genes involved are often associated with the horizontal gene pool (17,20,46).…”

Description of Citricoccus nitrophenolicus sp. nov., a para-nitrophenol degrading actinobacterium isolated from a wastewater treatment plant and emended description of the genus Citricoccus Altenburger et al. 2002

“…no information pNP with ammonium as nitrogen source resulted in the production of stoichiometric amounts of nitrite (Fig. 3) as previously observed for bacterial aerobic degradation of pNP (Chauhan et al 2000;Löser et al 1998, Prakash et al 1996Roldan et al 1998;Tomei et al 2003;Qiu et al 2006). When incubated with both acetate (50 mM) and pNP (370 and 700 lM), pNP was completely degraded in 32 h and 48 h, respectively (Fig.…”

“…Degradation of pNP occurs by different pathways (Kitagawa et al 2004;Singh and Walker 2006;Perry and Zylstra 2007) and has mainly been reported in aerobic Gram-negative bacteria like Pseudomonas (Löser et al 1998) and Moraxella strains (Spain and Gibson 1991) as well as Gram-positive bacteria of the genera Rhodococcus (Gemini et al 2005) and Bacillus (Kadiyala and Spain 1998).…”

Microbial remediation of nitro-aromatic compounds: An overview

“…For this purpose, microbes have evolved diverse pathways for their mineralization. Extensive research in the last two decades on this aspect has led to isolation of a number of organisms with potential to degrade nitro-aromatic compounds (Schmidt et al, 1987; Lenke and Knackmuss, 1992; Boopathy and Kulpa, 1993;Hanne et al, 1993;Marvin-Sikkema and de Bont, 1994;Prakash et al, 1996;Hughes et al, 1998a, b;Loser et al, 1998;Peres et al, 1999;Razo-Flores et al, 1999;Nishino and Spain, 2002;Dutta et al, 2003;Kulkarni and Chaudhari, 2006a-c). However, the number of organisms utilizing nitro-aromatics as a sole source of C and/or N is very rare.…”

“…Nitrobenzene Formation of hydroxylaminobenzene which undergoes Bamberger rearrangment to produce 2-aminophenol with release of NH 3 Prakash et al, 1996;Loser et al, 1998;Kulkarni and Chaudhari, 2006a, c) and 4-chloro 2-nitrophenol are first hydroxylated at the nitro group, with a release of nitrite to form ortho-or para-dihydroxybenzene. Pesticides such as parathion and methyl parathion are first hydrolyzed to 4-nitrophenol and subsequently hydroxylated at the nitro group (Nelson, 1982;Ye et al, 2004).…”