Prediction of the Metabolic Activity of a MixedBacillus Culture during the Biodegradation of Wastewater from the Potato Industry

Abstract

The advantages of the analysis of electrical impedance changes for the prediction of the metabolic activity of mixed Bacillus cultures used for high temperature industrial wastewater utilization are demonstrated. The primary aim of this study was to investigate the possibilities of a fast assessment of the biodegradative capabilities of microorganisms, their requirements regarding the medium composition as well as the inhibiting effect of high-strength (i.e., highly concentrated) wastewaters on microbial growth. Four mixed Bacillus cultures were cultivated at 45 and 55 °C on two kinds of wastewater from the potato starch industry. The course of changes in the electrical impedance during the cultivation of the bacteria in the examined wastewaters was described by the mathematical Gompertz model. Three kinetics parameters (maximum rate of impedance changes, Imax; the time necessary to reach, Imax, TI; and the duration of the lag phase, λ) were proposed for the statistical analysis of the bacterial metabolic activity. The temperature of the biodegradation process and the type and strength of the wastewater significantly influenced the microbial metabolic activity of the mixed bacterial cultures used. Monitoring of the impedance changes, caused by microbial metabolism, and its proposed mathematical specification allowed for predicting the dynamics of the microbiological degradation of wastewater and estimating the inhibiting effects of these media on the microorganisms.