Microbiologic Reaction

The order of a complete microbiologic reaction, in the stationary phase of development of harvests, normally reaches to zero if the concentration of the sustrate (which must be very soluble) is maintained constant.. the order of the reaction of this type naturally does not reflect the metabolic mechanism in its complexity, instead only the limitant step with respect to the speed of one sequence of reactions. If the substrate is not very soluble and the metabolic process is fast, the limitation of the velocity of the dissolution of, for example, sulphured minerals depends on the corresponding product of sollubility and the reaction follows the first order. In the bacterial lixiviation of concentrates of chalcopyrites, for example, the first order of the total reaction was found.

If the transfer were of one electron of a metabollic system of the bacterias the slowest step of all the reactions, the speed of the lixiviation would depend on the electropotential redox of the metallic sulphur, which has been mainly contradicted; but with certain limitations, the correlation between speed of the lixiviation of the metallic sulphurs and the product of solubility has been found.

A reaction of the first order can also consequence of the limitation by the difusion of the ions which pass by the surface layer of the mineral. In this case, the speed of the lixiviation would depend on the agitation.