Specific growth rates were determined from the exponential phases when the substrate has been consumed at the fastest rate. These specific growth rates that reflect the affinity of cells to the carbon source were used in the growth kinetics estimation studies. Figure 4 shows that the cell growth at the different initial concentrations of o- cresol.
In order to evaluate growth kinetics, the biomass growth data from different initial o- cresol degradation batch experiments were plotted on a semi-logarithmic graph. This suggests that o- cresol is an inhibitory type of substrates. Substrate inhibition is a feature of phenol metabolism for different microorganisms at different concentration levels as suggested by Bajaj et al. Furthermore, Chung et al.
K S is that value of the limiting nutrient concentration at which the specific growth rate is half of its maximum value. The values of the growth kinetics parameters obtained for o- cresol are given in Table 1. The specific growth rate that we achieved is remarkable as we compare it to the similar studies Gallego et al. The kinetic parameters gathered from batch culture experiments indicate that o -cresol is preferred carbon source compared to phenol Bajaj et al.
Phenol degradation studies have revealed that Haldane constants are consistent to o- cresol inhibition kinetic as we show here. Information about the kinetics of o -cresol biodegradation is useful for optimal design and operation of aerobic biological treatment reactors. A large variety of carriers or supports are used for cell immobilization. Degradation of phenol has also been performed using immobilization methods Chen et al.
This study examined the ability of carriers as support material to promote the attachment of P. Pumice, granular silica gel, amberlite IRA and exhausted perlite were used as support materials. As a comparison for absorption rates of different support materials and ca-alginate beads can be seen in Figure 6. Pumice was chosen as a support material rather than the amberlite because it is less expensive. The next recycled system studies were conducted on the usage of ZrOCl 2 activated pumice.
The recycled packed bed reactor was examined for estimated facilities of biodegradation Figure 8. Bioreactor operating conditions: Flow rate F ; 1. Continuous measurement of o -cresol concentration allowed us to estimate the consumption of sole carbon source. Henry's law coefficient of o -cresol is 0. This information allows us to make an inference that the most of the consumption is because of the biodegradation.
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The packed bed reactor, which was composed of Ca-alginate beads in which carried immobilized cells, lasted at least two cycles as well as the other packed bed reactor with full of cell immobilized pumice particles. The degradation times of Ca-alginate and pumice systems were approximately 18 hrs and 22 hrs, respectively. After the second cycle results showed that performance of the degradation began to decrease.
Substrate diffusion limitations in the reactor might cause inadequate supply of oxygen or nutrients to the cells.
This incompetent environment produced cell death. The packed bed reactor with Ca-alginate beads was more stable than pumice. Deformation of particles and detachment of cells from the surface of pumice were the main causes for this result. Most of the recent kinetic studies are performed by using phenol, whereas in our approach we have used o- cresol which is also a phenolic compound and has a very effective toxicity.
The biodegradation kinetics of o -cresol was examined in batch experiments at varying initial o -cresol concentrations. At high substrate concentrations o -cresol was toxic to the microbial activities and as a result the o -cresol biodegradation. The kinetic parameters of o -cresol biodegradation by P. The novel approach of our study is the elimination of costs that may arise during temperature fixation and from expensive carbon sources needed for basic cell maintenance.
We provide a strong demonstration of feasibility of Pseudomonas putida that has been exposed to acclimatization process for biodegradation of o- cresol.
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As a conclusion, we offer several cell immobilization options for more effective and recurrent systems as we demonstrated in a toy model. In the light of results that were gathered from our recycled packed bed reactor, large scale wastewater treatment systems can be established. Kinetics model for growth of Pseudomonas putida F1 during benzene, toluene and phenol biodegradation. Process Biochemistry , vol. Toxicological profile for cresols. Water Quality Control Handbook.
New York: McGraw-Hill. ISBN Adsorption of phenol on surface modified carbon black from its aquatic solution. Influence of surface-chemical structure of carbon on adsorption of phenol. Bulletin of the Chemical Society of Japan , vol. Phenol degradation kinetics of an aerobic mixed culture. Biochemical Engineering Journal , vol. Biodegradation of phenol and phenol-related compounds by psychrophilic and cold-tolerant alpine yeasts. Chemosphere , vol. CHEN, K.
CRESOL - National Library of Medicine HSDB Database
Degradation of phenol by PAA-immobilized Candida tropicalis. Enzyme and Microbial Technology , vol. Mass transfer effect and intermediate detection for phenol degradation in immobilized Pseudomonas putida systems. Biodegradation of phenol by Pseudomonas putida immobilized in polyvinyl alcohol PVA gel. Journal of Hazardous Materials , vol. Kinetics and metabolic versatility of highly tolerant phenol degrading Alcaligenes strain TW1.
Degradation and detoxification of cresols in synthetic and industrial wastewater by an indigenous strain of Pseudomonas putida in aerobic reactors. Environmental Toxicology , vol.
Toxicological profiles - Dinitrocresols
Trichloroethylene and chloroform degradation by a recombinant pseudomonad expressing soluble methane monooxygenase from Methylosinus trichosporium OB3b. Applied and Environmental Microbiology , vol. KAR, S. Biodegradation of phenol and cresol isomer mixtures by Arthrobacter. World Journal of Microbiology and Biotechnology , vol. Kinetics for aerobic biological treatment of o -cresol containing wastewaters in a slurry bioreactor: Biodegradation by utilizing waste activated sludge.
Biodegradation of phenol by acclimatized Pseudomonas putida cells using glucose as an added growth substrate. Modeling the effect of immobilization of microorganisms on the rate of biodegradation of phenol under inhibitory conditions. Water Research , vol. The role of prostaglandin synthesis in prostate cancer.
Br J Urol Int ; Over-expression of cyclooxygenase-2 in human prostate adenocarcinoma. Prostate ; Cyclooxygenase-2 expression inhepatocellular carcinoma. Hepatogastroenterology ; Molecular biology of prostate cancer. World J Urol ; Interleukin-3 and bryostatin-1 mediate hyperphosphorylation of BCL2a in association with suppression of apoptosis. J Biol Chem ; Rayman MP. The importance of selenium to human health. Lancet ; Blood and plasma selenium levels and GSH-PX activities in patients with arterial hyperten- sion and chronic heart disease.
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