Es wird uber Untersuchungen zum aeroben biologischen Abbau von 2,4-Dinitrotoluol (2,4-DNT) unter Nachweis der vollstandigen Mineralisierung berichtet. Es kam ein Stamm Pseudomonas sp. DNT von Spain und Nishino zum Einsatz. Der Abbau wurde sowohl in diskontinuierlichen Kulturen zur Bestimmung kinetischer und stochiometrischer Koeffizienten als auch in kontinuierlichen Kulturen untersucht. Aus den Batch-Versuchen konnte ein massebezogener Ertragskoeffizient fur die Biomasse (Trockenmasse) von YB/S = (0.30 ± 0,05) g g−1 bestimmt werden. Durch Anpassung der Meswerte an die Monod-Kinetik wurden μmax = 0.1 h−1 und KS = 0.01…0.03 mmol L−1 bestimmt. Es wurde gezeigt, das 2,4-DNT nicht nur als Kohlenstoff- und Energiequelle, sondern auch als alleinige Stickstoffquelle dient. Im Festbettumlaufreaktor lies sich ein Abbau von 92…97% bei einer Belastung mit 2,4-DNT von maximal 95 mg L−1 h−1 erzielen. Durch Messung des DOC und des freigesetzten Nitrits und Nitrats wurde die vollstandige Mineralisierung des 2,4-DNT bestatigt. Ein Teil des freigesetzten Nitrits wurde simultan nitrifiziert.
Biological Degradation of 2,4-Dinitrotoluene in a Continuous Bioreactor and Kinetic Studies
Experimental results on the aerobic biological degradation with complete mineralization of 2,4-dinitrotoluene (2,4-DNT) are presented. A culture of Pseudomonas sp. DNT from Spain and Nishino was used. The degradation was examined with batch cultures for the determination of kinetic and stoichiometric coefficients. Further experiments were carried out with a continuous culture in a fixed-bed reactor with recirculation in order to obtain high degradation rates. The reactor was packed with ceramic Raschig rings (55 mL) and had a liquid reaction volume of 160 mL. The minimal salt media from Spanggord et al. with and without (NH4)2S)4 as nitrogen source was used as substrate. 2,4-DNT was the sole source of carbon and energy. From batch experiments a yield coefficient YB/S = (0.30 ± 0.05) g g−1 was calculated from a mass balance of the elements. This result was confirmed by calculations using literature data. Fitting the experimental data to the Monod equation, μmax = 0.1 h−1 and KS = 0.01…0.03 mmol L−1 were obtained. It was demonstrated by batch experiments that 2,4-DNT is not only used as the source of carbon and energy but also as the nitrogen source. In the fixed-bed reactor, a degradation of 92…97% was reached with a maximal 2,4-DNT load of 95 mg L−1 h−1. The rate of continuous degradation could be described by a pseudo-first-order reaction (k = 9.73 h−1). The complete mineralization of 2,4-DNT was verified by the measurement of DOC and the formed nitrite and nitrate. The formed nitrite was nitrified simultaneously. It was demonstrated by these experiments that large scale biological treatment of industrial effluent containing 2,4-DNT may be successful.
[1]
Major,et al.
Biodegradation of 2,4- and 2,6-dinitrotoluene by freshwater microorganisms. (Reannouncement with new availability information)
,
1992
.
[2]
M. Gold,et al.
Degradation of 2,4-dinitrotoluene by the lignin-degrading fungus Phanerochaete chrysosporium
,
1992,
Applied and environmental microbiology.
[3]
K. Mortelmans,et al.
Biodegradation of 2,4-dinitrotoluene by a Pseudomonas sp
,
1991,
Applied and environmental microbiology.
[4]
Ian W. Marison,et al.
The use of calorimetry in biotechnology
,
1989
.
[5]
U. Wiesmann.
Kinetik der aeroben Abwasserreinigung durch Abbau von organischen Verbindungen und durch Nitrifikation
,
1986
.
[6]
J. Cornell,et al.
Identification of biotransformation products from 2,4-dinitrotoluene
,
1978,
Applied and environmental microbiology.
[7]
G. Bringmann,et al.
[Biological degradation of nitrotoluol and nitrobenzol using Azobacter agilis].
,
1971,
Gesundheits-Ingenieur.
[8]
O. H. Lowry,et al.
Protein measurement with the Folin phenol reagent.
,
1951,
The Journal of biological chemistry.