Ralstonia eutropha as a biocatalyst for desulfurization of dibenzothiophene.
The potential of Ralstonia eutropha as a biocatalyst for desulfurization of dibenzothiophene (DBT) was studied in growing and resting cell conditions. The results of both conditions showed that sulfur was removed from DBT which accompanied by the formation of 2-hydroxybiphenyl (2-HBP). In growing cell experiments, glucose was used as an energy supplying substrate in initial concentrations of 55 mM (energy-limited) and 111 mM (energy-sufficient). The growing cell behaviors were quantitatively described using the logistic equation and maintenance concept. The results indicated that 2-HBP production was higher for the energy-sufficient cultures, while the values of the specific growth rate and the maintenance coefficient for these media were lower than those of the energy-limited cultures. Additionally, the kinetic studies showed that the half-saturation constant for the energy-limited cultures was 2 times higher than the energy-sufficient ones where the inhibition constant (0.08 mM) and the maximum specific DBT desulfurization rate (0.002 mmol gcell-1h-1) were almost constant. By defining desulfurizing capacity (DDBT) including both the biomass concentration and time to reach a particular percentage of DBT conversion, the best condition for desulfurizing cell was determined at 23% gcellL-1h-1which corresponded with the resting cells that were harvested at the mid-exponential growth phase.
Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran.
Azita
A
Dejaloud
Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran.
Farzaneh
F
Vahabzadeh
Department of Chemical Engineering, Razi University, Kermanshah, Iran. a.habibi@razi.ac.ir.
Alireza
A
Habibi
D055162:Biocatalysis; D001673:Biodegradation, Environmental; D001713:Biphenyl Compounds; D020118:Cupriavidus necator; D007700:Kinetics; D013455:Sulfur; D013876:Thiophenes
D001713:Biphenyl Compounds; D013876:Thiophenes; D013455:Sulfur; C004369:2-phenylphenol; C016366:dibenzothiophene
Dibenzothiophene biodesulfurization; Kinetic study; Logistic equation; Maintenance energy; Ralstonia eutropha