Assessment of toxicity using dehydrogenases activity and mathematical modeling

Abstract

Dehydrogenase activity is frequently used to assess the general condition of microorganisms in soil and activated sludge. Many studies have investigated the inhibition of dehydrogenase activity by various compounds, including heavy metal ions. However, the time after which the measurements are carried out is often chosen arbitrarily. Thus, it can be difficult to estimate how the toxic effects of compounds vary during the reaction and when the maximum of the effect would be reached. Hence, the aim of this study was to create simple and useful mathematical model describing changes in dehydrogenase activity during exposure to substances that inactivate enzymes. Our model is based on the Lagergrens pseudo-first-order equation, the rate of chemical reactions, enzyme activity, and inactivation and was created to describe short-term changes in dehydrogenase activity. The main assumption of our model is that toxic substances cause irreversible inactivation of enzyme units. The model is able to predict the maximum direct toxic effect (MDTE) and the time to reach this maximum (TMDTE). In order to validate our model, we present two examples: inactivation of dehydrogenase in microorganisms in soil and activated sludge. The model was applied successfully for cadmium and copper ions. Our results indicate that the predicted MDTE and TMDTE are more appropriate than EC50 and IC50 for toxicity assessments, except for long exposure times.

Potential causes of high performance of pure-oxygen aerobic granules in SBR under high organic loading condition

“…) (Yao et al, 2010; ) and the detailed steps were performed as previously described (Matyja et al, 2016). …”

“…Dehydrogenase is the predominant enzyme in the respiratory electron-transport chain and its activity dominates the performance of activated sludge flocs in wastewater treatment (Matyja et al, 2016;Yao et al, 2010 (Fig. 7a).…”

“…on account of an increase in influent organic loading (Tarjányi-Szikora et al, 2013;Zhang et al, 2016). There was the vigorous metabolism under HOLC, which in turn would enhance multiplication capacity of living organism in POAG and elevate removal performance of organic pollutants (Matyja et al, 2016;Zhang et al, 2016). show an increasing tendency with rising influent loading under HOLC and, at the same time, the removal efficiency of organic pollutants is stable, demonstrating great potential of POAG in wastewater treatment under HOLC.…”

“…It is characteristics of abundant biodiversity (Adav et al, 2009;Bernat et al, 2017;Meerburg et al, 2016), a dense and strong microbial structure (Adav et al, 2008;Moy et al, 2002), elevated activity of enzymes (Li and Chróst, 2006;Matyja et al, 2016;Tarjányi-Szikora et al, 2013;Yao et al, 2010Yao et al, , 2012Zhang et al, 2016) and a great plenty of EPS secretion (Badireddy et al, 2010;Caudan et al, 2014;Liu et al, 2004;Zhao et al, 2016;Zhu et al, 2012), which makes it harbor good performance under HOLC.…”

The matrix-based description approach for the multistage differential-algebraic processes

“…The multistage technological processes are often designed in technology, especially in biotechnology [1], [9], [10], [11], chemical engineering [4], [8], as well as in environmental engineering [13], [14], [15].…”