Growth rate influences reductive biodegradation of the organophosphorus pesticide demeton by Corynebacterium glutamicum.
The organophosphorous pesticide, demeton-S-methyl was transformed by Corynebacterium glutamicum in co-metabolism with more readily degradable substrates. Glucose, acetate and fructose were tested as growth substrates, and the highest demeton-S-methyl biotransformation average rate (0.78 mg l(-1) h(-1)) and maximum instantaneous rate (1.4 mg l(-1) h(-1)) were achieved on fructose. This higher efficiency seems to be linked to the atypical behavior of C. glutamicum grown on fructose, characterized by a prolonged period of accelerating growth instead of a constant growth rate observed on glucose or acetate. More precisely, for growth rates in the 0.1-0.4 h(-1) range, a direct coupling between the specific demeton-S-methyl consumption rate and the growth rate was demonstrated on fructose during batch-, steady state continuous- or continuous cultures with a controlled transient growth rate (accelerostat technology). The demeton-S-methyl biotransformation was more favoured during an acceleration phase of the growth rate.
Girbal
L
L
Laboratoire de Biotechnologie-Bioprocédés, UMR CNRS 5504 & UR INRA 792, Centre de Bioingénierie Gilbert Durand, INSA, Toulouse, France. girbal@insa-tlse.fr
Rols
J L
JL
Lindley
N D
ND
D001673:Biodegradation, Environmental; D001711:Biotransformation; D003352:Corynebacterium / Q000254:growth & development* / Q000378:metabolism*; D004222:Disulfoton / Q000378:metabolism*; D005285:Fermentation; D007306:Insecticides / Q000378:metabolism*; D010084:Oxidation-Reduction
D007306:Insecticides; D004222:Disulfoton