Multiple substrate growth kinetics of leptothrix discophora sp-6

Abstract

The growth parameter of Leptothrix discophora SP-6 were quantified on the basis of the steady-state concentrations and utilization rates of pyruvate, dissolved oxygen, and concentration of microorganisms in a chemostat operated at 25°C, pH 7.2, and an agitation rate of 350 rpm. The results showed that the microbial growth was limited by both pyruvate and dissolved oxygen. A combined growth kinetics model using Monod growth kinetics for pyruvate and Tessier growth kinetics for oxygen showed the best correlation with the experimental data when analyzed using an interactive multiple substrate model. The growth kinetics parameters and the respective confidence limits, estimated using the Monte Carlo simulation, were µmax = 0.576 ± 0.021 h-1, KsMp = 38.81 ± 4.24 mg L-1, KsTo = 0.39 ± 0.04 mg L-1, YX/p = 0.150 (mg microorganism mg-1 pyruvate), YX/o = 1.24 (mg microorganism mg-1 oxygen), the maintenance factors for pyruvate and oxygen were mp = 0.129 (mg pyruvate consumed mg -1 microorganism h-1 ) and mo = 0.076 (mg oxygen consumed mg-1 microorganism h-1), respectively.