Microkinetic Analysis of <i>n</i>‐<scp>H</scp>exane Biodegradation by an Isolated Fungal Consortium from a Biofilter: Influence of Temperature and Toluene Presence

Abstract

The kinetic study of a pollutant biodegradation is considered as one of the main steps in the characterization of a biofilter performance. In this research, an unidentified fungal consortium, which had been previously isolated from a compost biofilter treating n ‐hexane and toluene vapors, was used to study the biodegradation of n ‐hexane in a batch system. In order to evaluate the ability of the isolated fungi, the effect of operating temperature and pollutant concentration on the biodegradation process were studied. The n ‐hexane concentration in liquid phase was varied in the range of 5–25 mg L −1 and the temperature was altered between 25 and 45°C, using experiments designed with the help of central composite design. The maximum n ‐hexane biodegradation (95.7%) was obtained in optimum condition at 36.5°C and 8.6 mg L −1 . The kinetic investigations at 25 and 40°C presented that Haldane, Webb, and Yano models could predict the biodegradation well with R 2 &gt; 0.98. The kinetic parameters of Haldane model at 40°C were ν max = 3.57 (mg n ‐hexane (g biomass h) −1 ), K S = 9.57 (mg L −1 ), and K I = 20.48 (mg L −1 ). A sum kinetic model was used to study the interaction between the biodegradation of n ‐hexane and toluene. Toluene had a greater inhibition on n ‐hexane biodegradation ( I Tol, Hex = 9.47) much more than that for n ‐hexane on toluene ( I Hex, Tol = 4.65).