Variable‐volume accelerated system to evaluate the carbaryl biodegradation dynamics of a microbial community by differential analysis

Abstract

AbstractBACKGROUNDOne of the continuous cultivation methods for acquiring quantitative data on microbial metabolism under various environmental conditions within a single experiment is the accelerostat culture system (A‐stat). It allows the rapid analysis and quantitative evaluation of the effect of environmental on the functional response of microorganisms, which is reflected by the cultural biokinetic parameters. In a classical accelerostat system, equipment and control programs maintain a constant acceleration (a) of the culture's dilution rate D[t] = Do + at. Unlike the conventional A‐stat, in which a linear change in the dilution rate is obtained, a new variant, here named a variable‐volume accelerated (VVA) system, the acceleration is variable (a = f[t]); thus, D[t] = Do + a[t]. This system requires minimal manual intervention and presents operational advantages over the classical A‐stat; the reactor's D[t] change is achieved under a simple condition: the input and output flow rates are unequal; Fin ≠ Fout.RESULTSUsing carbaryl as a study model, the dynamic behavior of the VVA system was evaluated by differential analysis of the experimental data obtained by cultivating a carbaryl‐degrading microbial community. Mathematical analysis of the VVA system established the acceleration profile a[t] for the study, quantifying the impact of dilution rate on the microbial community's biokinetic and stoichiometric parameters.CONCLUSIONThe VVA system allowed observation of the effect of the D[t] gradient on the rate of change of kinetic parameters that define the physiological state of the microbial culture, together with the microbial community's macromolecular composition. © 2024 Society of Chemical Industry (SCI).