Mathematical Modelling of the Reduction, Substrate and Metal Inhibition Kinetics of Molybdate

A molybdenum-reducing bacterium with the novel ability to decolourise various dyes is reported. The absorption spectrum of the molybdenum reduced product suggested that it is a reduced phosphomolybdate. Optimum conditions for molybdenum reduction were ammonium sulphate 4g/L, pH of 8 and at 37°C. Arabitol was the best electron donor. The highest Mo-blue was observed at the phosphate concentration of 2.5 mM and sodium molybdate at 10 mM. Pseudomonas sp. MM02 was able to decolourise the dye tartrazine maximally at 75.9%, followed by Reactive Red 120 at 75.4 % and Reactive Brown 10 at 63.63%. Substrate inhibition kinetics was investigated and based on the best model; Haldane, the maximum specific reduction rate, the concentration of substrate at the half-maximal reduction rate, and inhibition constant represented by qmax, ks and Ki were 6.71 μmole Mo-blue h-1, 9.97 mM and 65.59 mM, respectively