Extended kinetic model for DBT desulfurization using Pseudomonas putida CECT5279 in resting cells.

Abstract

Dibenzothiophene desulfurization by Pseudomonas putida CECT5279, genetically modified microorganism, in resting cells is studied. In previous works, operational conditions were established and a kinetic model describing the four serial reactions was proposed. Later studies showed the existence of two characteristic growth times of this bacterium, 5 and 23 h, offering maximum activities in the desulfinase and the monooxygenase enzymes of this route. The combination of cells collected at 5 and 23 h of growth time was proved to be a very effective biocatalyst for desulfurization in resting cells. In this work, the previously proposed kinetic model is extended and applied to these cells with different ages. Moreover, other extension is considered, taking into account the activity loss of the enzymes involved in 4S route, and the influence of biomass concentration employed. These extensions are of considerable importance in order to scale-up the process. The kinetic model developed is able to fit the experimental results for resting cell operation with cells of different ages, in different concentration taking into account the enzyme deactivation.