Effect of pH and Temperature on Iron Oxidation by Mesophilic Mixed Iron Oxidizing Microflora

The aim of the work described in this paper was to establish the effect of physical parameters such as pH and temperature on the microbial growth and iron oxidation rate of an isolated iron oxidizing bacterial strain from mine effluent. The bacterial lag phase was reduced to zero by repeated subculturing in fresh nutrient media. The rate of iron oxidation was considered as the growth rate of the microorganism in its logarithmic phase. Variation of pH showed an inadequate effect within the range from 1.5 to 2.5 ensuing growth flexibility in acidic medium. With variation of temperature from 293 to 313 K, the rate increased up to 303 K and gradually decreased beyond this temperature. At the optimized values of pH 2.0 and temperature 303 K, the iron oxidation rate was 2.17 x 10(-4) kg.m(-3)s(-1). [doi: 10.2320/matertrans.MER2008051]