Influence of the concentration of phosphorus, potassium, calcium and iron compounds on the microbial reduction of sulphates.

In the reduction process of sulphates by Desulfovibrio desulfuricans suitable concentration of mineral salts plays an important role. In particular, different K2HPO4, CaCl2 and Fe(NH4)2(SO4)2 content in the reaction medium has an observable effect on the reduction degree (x'), the induction time (t0) and the reduction rate constant (k). These data were recorded for 9 liquid media characterized by different content of mineral salts. The reaction rate constants were calculated for the reduction process in each medium. Optimal reduction conditions exists at the following element concentration ratios: P/S=0.068, K/S=0.086, Fe/S=0.08, N/S=0.33, C/S=1.80, Ca/S=0.03, Cl/S=0.80.