Relevance of the Luong model to describe the biodegradation of phenol by mixed culture in a batch reactor

Abstract

The kinetics of phenol biodegradation by mixed culture in a batch reactor was investigated over a wide range of initial phenol concentrations (40-350 mg L -1 ). The temperature (30°C), the stirring velocity (200 rpm), mineral salt supplementation, namely NaH 2 PO 4 (3 g L -1 ), KH 2 PO 4 (3 g L -1 ), MgSO 4 (0.1 g L -1 ), (NH 4 ) 2 SO 4 (1 g L -1 ), as well as the initial pH (8) were kept constant. All experiments were carried out at a given initial bacterial concentration of 0.08 g L -1 (based on the optical density determination, 0.079). Irrespective of the culture conditions, total phenol degradation was recorded for a culture time ranging from 15.6 to 49.0 h. In addition, the optimal value of the maximum specific growth rate was observed for 125 mg L -1 of phenol. These results show the relevance of the specific microbial consortium used. The Luong equation accurately matched growth kinetics and enabled the relation between the maximum specific growth rates (μ m ) and the initial phenol concentration (S o ) to be described. It could also be used to deduce the substrate saturation coefficient (K s ) and the maximum substrate concentration (S m ) above which growth ceases. The kinetic constants of the Luong equation for phenol were m m ¼ 1:04 h À1 ; K s ¼ 153:2 mg L À1 ; S m ¼ 540 mg L À1 and n ¼ 0:9, respectively.

Growth Inhibition Kinetics of Acetonitrile Biodegradation

“…In some circumstances, at high substrate concentrations, the substrate itself, as a result of its repressive and toxic properties, inhibits microbial growth rate. To date, the majority of the Luong model reported for microbial degradation of xenobiotics has focused on phenol-degrading bacteria [28,51,52] and molybdenum-reducing consortium [53,54]. Perhaps, this the first work to model the degradation of acetonitrile using bacterial consortium.…”

“…This is despite the fact that several other models have been shown to be more accurate for a single substrate-inhibiting compound, such as phenol. Aside from the commonly reported Haldane model [26], numerous other models such as Edward [27] and Luong [28,29] have been found to be optimal. As a result, in some cases using comprehensive models instead of the Haldane might be appropriate.…”

Modelling Growth Kinetics of <i>Klebsiella</i> sp. FIRD 2 on TBT-Resistant Containing Lead

“…Discontinuous model was developed due to the fact that in the previous models developed (Webb, Andrews And Noack, and Haldane), only inhibitory effect on microbial growth were described but could not explain or adequately model for certain situations where the growth rate completely ceased or becoming zero at very high substrate concentration. While Luong in 1987 developed a continuous type of the model above that has popular support due to its close agreement to experimental data in some cases (Halmi et al, 2014;Hamitouche et al, 2012;Nickzad et al, 2012;Othman et al, 2013). A central attraction of the Luong model is its ability to successfully predict the value of S m , the maximum substrate concentration above which growth is completely inhibited.…”

Substrate Inhibition Kinetics Models for Fitting the Growth Rate of Phenol by an Immobilized Pseudomonas putida

“…In many different literatures, the Haldane model is used to represent substrate inhibition of growth or degradation rate.While other models have been proved to be more accurate when considering many substrate-inhibiting chemicals at once, such as phenol, this one continues to be used. As an illustration, the Haldane model isn't the only one out there [20], In addition to Luong's model, additional models have been proven to be superior [21,22] and Edward [23]. Therefore, in certain cases, the Haldane may be superseded by the use of the comprehensive models currently at hand.…”