Transformation of 2,4,6-trinitrotoluene (TNT) by immobilized Phanerochaete chrysosporium under fed-batch and continuous TNT feeding conditions.
The cometabolic transformation of 2,4,6-trinitrotoluene (TNT) by an immobilized Phanerochaete chrysosporium culture was investigated under different TNT and/or glycerol feeding conditions in a 5-L reactor. In the fed-batch feeding mode, as a result of four spiking events at an average feeding rate of 20 mg TNT L(-1) d(-1) and 250 mg glycerol L(-1) d(-1), the initial TNT transformation rate and the glycerol uptake rate of the 7-day-old immobilized cell culture were 2.41 mg L(-1) h(-1) and 16.6 mg L(-1) h(-1), respectively. Thereafter, the TNT fed into the reactor depicted a negative effect on the cell physiology of P. chrysosporium, i.e., both rates decreased constantly. At 32 mg TNT L(-1) d(-1) feeding rate, also in the presence of glycerol (200 mg L(-1) d(-1)), this effect on the fungal cell metabolism was even more significant. When TNT was fed alone at 3.7 mg L(-1) d(-1), it showed an initial 0.75 mg L(-1) h(-1) rate of TNT transformation, i.e., one-third the initial level observed in the presence of glycerol. In contrast, in the continuous feeding mode (dilution rate, D = 0.11 d(-1)), at 5.5 mg TNT L(-1) d(-1) and 220 mg glycerol L(-1) d(-1), the immobilized cell culture exhibited a constant TNT transformation rate for cultivation periods of 50 and 61 days, under uncontrolled and controlled pH conditions, respectively. Thereafter, during the latter experiment, 100% TNT biotransformation was achieved at 1,100 mg L(-1) d(-1) glycerol feeding rate. Immobilized cells (115-day-old), sampled from a continuous TNT feeding experiment, mineralized [(14)C]-TNT to a level of 15.3% following a 41-day incubation period in a microcosm.
Rho
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D
Biotechnology Research Institute, National Research Council (NRC) Canada, 6100 Royalmount Avenue, Montréal, QC, H4P 2R2, Canada. denis.rho@nrc.ca
Hodgson
J
J
Thiboutot
S
S
Ampleman
G
G
Hawari
J
J
D019149:Bioreactors; D001711:Biotransformation; D018914:Cells, Immobilized; D003470:Culture Media; D005990:Glycerol / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D020075:Phanerochaete / Q000378:metabolism*; D014303:Trinitrotoluene / Q000378:metabolism*
D003470:Culture Media; D014303:Trinitrotoluene; D005990:Glycerol