Metabolism of 2,4-dinitrotoluene (2,4-DNT) by Alcaligenes sp JS867 under oxygen limited conditions

Citation
Bf. Smets et Rj. Mueller, Metabolism of 2,4-dinitrotoluene (2,4-DNT) by Alcaligenes sp JS867 under oxygen limited conditions, BIODEGRADAT, 12(4), 2001, pp. 209-217
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biotecnology & Applied Microbiology
Journal title
BIODEGRADATION
ISSN journal
0923-9820 → ACNP
Volume
12
Issue
4
Year of publication
2001
Pages
209 - 217
Database
ISI
SICI code
0923-9820(2001)12:4<209:MO2(BA>2.0.ZU;2-C
Abstract
Transformation of 2,4-dinitrotoluene (2,4-DNT) by Alcaligenes JS867 under v arying degrees of oxygen limitation was examined. Complete 2,4-DNT removal was observed under oxygen excess with near stoichiometric release (83%) of nitrite. Average kinetic parameters were estimated based on a dual-Monod bi okinetic model with 2,4-DNT and O-2 as growth limiting substrates. The nega tive impact of nitrite accumulation on the reaction rate was adequately des cribed by inclusion of a noncompetitive inhibition term for NO2-. Under aer obic conditions, mu (max), K-sDNT, and K-iNO were 0.058(0.004) hr(-1), 3.3( +/-1.3) mg 2,4-DNT/L, and 1.2(+/-0.2) hr(-1,) respectively. At increasing o xygen limitation, rates of 2,4-DNT disappearance and nitrite production dec reased and incomplete removal of 2,4-DNT commenced. JS867 was able to use N O2- as a terminal electron acceptor when grown on glucose or succinate unde r anaerobic conditions. However, during growth on 2,4-DNT and under O-2-lim ited conditions, JS867 did not use released nitrite as electron acceptor. T he nearly constant molar ratios of DNT removed over NO2- released under var ious degrees of oxygen limitation suggested that oxygenolytic denitration p athways continued. No evidence of nitroreduction was obtained under the exa mined oligotrophic conditions. JS867 displayed a high affinity for oxygen c onsumption with K-SO 2 value of 0.285(+/-0.198) mg O-2/L. Our results indic ate that under oligotrophic conditions with 2,4-DNT as dominant carbon sour ce, oxygen availability and nitrite accumulation may limit 2,4-DNT biominer alization, but the accumulation of reduced 2,4-DNT transformation products will be small.