Substrate inhibition kinetics: Phenol degradation by Pseudomonas putida

Abstract

SummaryA pure culture of Pseudomonas putida was grown in both a batch and continuous culture using phenol as the limiting substrate. Of two substrate inhibition models examined, the Haldane function was found to statistically best describe the kinetics. The applicable kinetic constants were either measured ( p~, K I ) or estimated ( K s ) from the experimental data. Particularly in the continuous culture, wall growth was found to exert significant effects on the broth biomass concentration and phenol conversion, both of which decreased with increasing amounts of wall growth. These effects are opposite to those predicted by wall growth models and to experimental results of others using mixed culture (activated sludge) systems.

Kinetics of batch microbial degradation of phenols by indigenous Pseudomonas fluorescence

“…Thus, it is observed that as the initial phenol concentration increased the duration of the lag phase increased; and thereby, prolonging the biodegradation time as a result of decrease in the rate of degradation. This observation is supported by the earlier works of Andrews (1968), Hill and Robinson (1975), Collins and Daugulis (1997), and Oboirien et al (2005). According to Prpich and Daugulis (2005), the rate of substrate consumption was suggested to be the most important measure of microbe performance.…”

“…A variety of techniques involving physical, chemical and biological methods have been used for the removal of phenol from industrial effluents and contaminated The meta-cleavage pathway for the biodegradation of phenol A= Phenol, B= Catechol, C= 2-Hydroxymuconic semialdehyde, D= 2-Hydroxymuconate, E= 2-Oxo-4-enoadipate, F= 2-Oxo-penta-4-enoate, G= Pyruvate, H= Acetaldehyde, I= Acetyl Co A, E1= Monooxygenase phenol hydroxylase, E2=Catechol-2, 3-dioxygenase, E3= Hydrolase, E4= Dehydrogenase, E5= Isomerase, E6= Decarboxylase, E7= Hydrotase, E8= Aldolase waters with bioremediation receiving the most attention due to its environmental friendliness, its, ability to completely mineralize toxic organic compounds and of low-cost (Kobayashi and Rittman, 1982;Prpich and Daugulis, 2005). Microbial degradation of phenol with different initial concentrations ranging from 50-2000 mg/L have been actively studied using shake flask, fluidized-bed reactor, continuous stirred tank bioreactor, multistage bubble column reactor, air-lift fermenter and two phase partitioning bioreactor methods (Bettmann and Rehm, 1984;Sokol, 1988;Annadurai et al, 2000;Reardon et al, 2000;Ruiz-ordaz et al, 2001;Oboirien et al, 2005;Prpich and Daugulis, 2005;Saravanan et al, 2008) and these studies have shown that phenol can be aerobically degraded by wide variety of fungi and bacteria cultures such as Candida tropicalis (Ruiz-ordaz et al, 2001, Chang et al, 1998Ruiz-ordaz et al, 1998); Acinetobacter calcoaceticus (Paller et al, 1995); Alcaligenes eutrophus (Hughes et al, 1984;Leonard and Lindley, 1998); Pseudomonas putida (Hill and Robinson, 1975;Kotturi et al, 1991;Nikakhtari and Hill, 2006); and Burkholderia cepacia G4 (Folsom et al,1990, Solomon et al,1994. In microbial degradation of phenol under aerobic conditions, the degradation is initiated by oxygenation in which the aromatic ring is initially monohydroxylated by a mono oxygenase phenol hydroxylase at a position ortho to the pre-existing hydroxyl group to form catechol.…”

“…Depending on the type of strain, the catechol then undergoes a ring cleavage which can occur either at the ortho position thus initiating the ortho pathway that leads to the formation of succinyl Co-A and acetyl Co-A or at the meta position thus initiating the metapathway that leads to the formation of pyruvate and acetaldehyde. Feist ands Hegeman (1969), Hill and Robinson (1975) and Leonard and Lindley (1998) have described the biodegradation or metabolism of phenol by Pseudomonas putida, Pseudomonas cepacia, and Alcaligenes eutrophus respectively via the meta cleavage pathway; while, Paller et al (1995) described the biodegradation of phenol by Acinetobacter calcoacetium via the ortho cleavage pathway.…”

Analysis of growth data with inhibitory carbon sources

“…(l), (4), and (S)] or four [eqs. (2) and (3)] kinetic constants. The graphical methods (linearized forms such as Lineweaver-Burk, Edie plots, etc.…”

Substrate inhibition kinetics of phenol degradation by Pseudomonas fluorescence from steady state and wash-out data

“…Phenol is a reasonably common wastewater contaminant (Li and Humphrey, 1989), which has been found to be either toxic or lethal to fish and most types of microorganisms at relatively low concentrations (Hill and Robinson, 1975). Studies on microbial means of treating or removing phenols dates back to at least three decades.…”