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Characteristics of growth and EDTA degradation by chemostat culture of bacterial strain DSM 9103 were investigated. The effect of specific growth rate ( μ ) on mass cell yield ( Y X/S ), specific rate of EDTA uptake ( q S ) and the rate of Mg–EDTA degradation by a cell suspension ( q S rest ) was studied. Based on the experimental data, kinetic constants of dependencies q S ( S ) and μ ( S ) were determined. The rates of substrate and energy expenditures for cell maintenance, m S and m e , were 0.02 and 0.014 h −1 , respectively. High efficiency of DSM 9103 growth on EDTA in a chemostat was established; the maximum mass cell yield ( Y X/S m ) and the maximum energy cell yield ( η X/S m ) were as high as 35.3 and 50.5%, respectively. Results indicated that oxidation of side chains in the EDTA molecule by monooxygenase is coupled with energy utilization by the cells. Cells harvested from a chemostat (resting cells) retain the capability of EDTA degradation, although at a rate about four to five times lower than growing cells. |
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