Kinetics of cometabolic biodegradation of 4-chlorophenol and phenol by Stenotrophomonas maltophilia KB2

Mixed microbial culture collected from effluent treatment plant of a coke oven industry has been studied for its phenol biodegrading potential under aerobic condition in a batch reactor. The result showed that, after acclimatization, the culture could biodegrade up to 700 mg/l of phenol. The results showed that specific growth rate of microorganisms and specific substrate degradation rate increased up to 300 mg/l of initial phenol concentration and then started decreasing. The biodegradation kinetics is fitted to different substrate inhibition models by MATLAB 7.1©. Among all models, Haldane model was best fitted (Root Mean Square Error = 0.0067) for phenol degradation. The different biodegradation constants (Ks, Ki, Sm, mmax, YX/S, kd) estimated using these models showed good potential of the mixed microbial culture in phenol biodegradation. Key words: Mixed culture, phenol biodegradation, kinetics, inhibition model.

Phenol biodegradation was studied in batch experiments using an acclimated inoculum and initial phenol concentrations ranging from 0.1 to 1.3 g/L. Phenol depletion and associated microbial growth were monitored over time to provide information that was used to estimate the kinetics of phenol biodegradation. Phenol inhibited biodegradation at high concentrations, and a generalized substrate inhibition model based on statistical thermodynamics was used to describe the dynamics of microbial growth in phenol. For experimental data obtained in this study, the generalized substrate inhibition model reduced to a form that is analogous to the Andrews equation, and the biokinetic parameters max, maximum specific growth; Ks', saturation constant; and Ki', inhibition constant were estimated as 0.251 h 2 1 , 0.011 g/L, and 0.348 g/L, respectively, using a nonlinear least squares technique. Given the wide variability in substrate inhibition models used to describe phenol biodegradation, an attempt was made to justify selection of a particular model based on theoretical considerations. Phenol biodegradation data from nine previously published studies were used in the generalized substrate inhibition model to determine the appropriate form of the substrate inhibition model. In all nine cases, the generalized substrate inhibition model reduced to a form analogous to the Andrews equation suggesting the suitability of the Andrews equation to describe phenol biodegradation data.

Coke oven wastewater from the iron and steel plant industry is composed of highly refractory and recalcitrant phenolic pollutants. To overcome the process instability, inhibition, and poor performance of coke oven wastewater treatment plants an efficient phenol degrading bacterial culture was isolated from the coke oven wastewater of a local steel plant industry in Odisha, India. In this study, the kinetics of phenol biodegradation by a newly isolated Pseudomonas citronellolis NS1 was carried out using batch shake flasks. The results revealed that the culture could degrade 1,500 mg/L−1 of phenol almost completely within 90 h as the sole source of carbon and energy. In addition, under these conditions, approximately 95.5% of the chemical oxygen demand (COD) and 98.5% of toxicity removal were achieved by the indigenous P. citronellolis NS1. The growth and biodegradation kinetics of the isolated Pseudomonas species were evaluated at phenol concentrations pf 50–1,500 mg/L−1. The specific growth rate of the culture followed the substrate inhibition kinetic pattern and the estimated biokinetic parameters were; μ = 0.246 h−1, Ksi = 890 mg/L−1, and Ks = 14.85 mg/L−1. Further, the effects of temperature on the biodegradation of phenol were carried out. The estimated values of maximum phenol biodegradation rate and the activation energy (Ea) of the enzyme-catalyzed reactions were 0.0152 h−1 and 47.21 kJ · mol−1 respectively at 36°C.

Kinetics of high strength phenol degradation using Bacillus brevis

Biodegradation of phenol in saline or hypersaline environments by bacteria: A review

Modelling of biological phenol removal in draw-fill reactors using suspended and attached growth olive pulp bacteria

Phenol biodegradation by mixed culture in batch reactor — Optimization of the mineral medium composition

In the present study, mixed microbial culture isolated from the sludge of effluent treatment plant of a refinery was tested for its phenol biodegradation potential under static batch condition. The result showed that, after acclimatization, the culture could biodegrade upto 750 mg L $^{-1}$ of phenol. 100% phenol degradation was achieved for the various concentrations studied. Kinetic study showed that specific growth rate of microorganisms and specific substrate degradation rate increased up to 300 mg L $^{-1}$ of initial phenol concentration and then started decreasing. The biodegradation kinetics was fitted to different substrate inhibition models by using optimization software tool (solver) in Microsoft office 2007. Among all models, Aiba model (μmax = 0.3187 h $^{-1}$ , K $_I$ = 400, R $^2$ = 0.915) and Edward Model (μmax = 0.0011 h $^{-1}$ , K $_I$ = 210 mg L $^{-1}$ , R $^2$ = 0.942) were fitted the best. Growth kinetics was also fitted well to the classical Haldane model. The values of inhibition constant, K $_I$ from Yano model indicated that this culture may well degrade phenol beyond 750 mg L $^{-1}$ .

Biodegradation of chlorophenols by immobilized pure-culture microorganisms

This study focuses on the kinetics of a pure strain of bacterium Rhodococcus sp. SKC, isolated from phenol-contaminated soil, for the biodegradation of phenol as its sole carbon and energy source in aqueous medium. The kinetics of phenol biodegradation including the lag phase, the maximum phenol degradation rate, maximum growth rate (Rm) and maximum yield coefficient (Y) for each Si (initial phenol concentration, mg/L) were fitted using the Gompertz and Haldane models of substrate inhibition (R2 > 0.9904, RMSE < 0.00925). The values of these parameters at optimum conditions were μmax = 0.30 h−1, Ks = 36.40 mg/L, and Ki = 418.79 mg/L, and that means the inhibition concentration of phenol was 418.79 mg/L. By comparing with other strains of bacteria, Rhodococcus sp. SKC exhibited a high yield factor and tolerance towards phenol. This study demonstrates the potential application of Rhodococcus sp. SKC for the bioremediation of phenol contaminate.

Biodegradation of phenol using bacteria is recognized as an efficient, environmentally friendly and cost-effective approach for reducing phenol pollutants compared to the current conventional physicochemical processes adopted. A potential phenol degrading bacterial strain Glutamicibacter nicotianae MSSRFPD35 was isolated and identified from Canna indica rhizosphere grown in distillery effluent contaminated sites. It showed high phenol degrading efficiency up to 1117 mg L–1 within 60 h by the secretion of catechol 1,2-dioxygenase via ortho intradial pathway. The strain MSSRFPD35 possess both the catechol 1,2 dioxygenase and catechol 2,3 dioxygenase coding genes that drive the ortho and meta pathways, but the enzymatic assay revealed that the strain cleaves catechol via ortho pathway. Haldane’s kinetic method was well fit to exponential growth data and the following kinetic parameter was obtained: μ∗ = 0.574 h–1, Ki = 268.1, Ks = 20.29 mg L–1. The true μmax and Sm were calculated as 0.37 h–1 and 73.76 mg L–1, respectively. The Haldane’s constant values were similar to earlier studies and healthy fitness depicted in correlation coefficient value R2 of 0.98. Phenol degrading kinetic’s was predicted using Haldane’s model as qmax 0.983, Ki′ 517.5 and Ks′ 9.152. Further, MSSRFPD35 was capable of utilizing different monocyclic and polycyclic aromatic hydrocarbons and to degrade phenol in the presence of different heavy metals. This study for the first time reports high phenol degrading efficiency of G. nicotianae MSSRFPD35 in the presence of toxic heavy metals. Thus, the strain G. nicotianae MSSRFPD35 can be exploited for the bioremediation of phenol and its derivatives polluted environments, co-contaminated with heavy metals.

Kinetics of phenolic and phthalic acid esters biodegradation in membrane bioreactor (MBR) treating municipal landfill leachate

The profound growth and development of industrial segments discharge enormous quantities of phenolic pollutants into the aquatic environment. Phenolic compounds are priority pollutants and their presence in the water system causes severe hazards to human health and many other living creatures. Thus, the removal of such toxic pollutants has gained a lot of attention in the past few decades. Biodegradation is a sustainable and efficient method for the removal of phenolic pollutants from the aquatic environment. Though microbial degradation of phenolic pollutants is well documented, enzymatic metabolic pathways, co-metabolic biodegradation, the use of sequential bioreactors, and the treatment of real-world industrial wastewater have yet to be adequately addressed. Therefore, the present review focuses on the assessment of biological removal of phenolic pollutants from the contaminated environment along with the various associated problems. In particular, the mechanism of ecotoxicity of phenolic pollutants on the living system, the functional enzymes and metabolic pathways involved in microbial degradation, including co-metabolic and co-culture degradation of phenolic pollutants, were elaborately reviewed. The use of aerobic granular sludge (AGS) in the treatment of recalcitrant wastewater has been addressed. The performances of various bioreactor systems are also compared. The prospects for resource recovery by photosynthetic bacteria that degrade phenolics are also discussed. • Represented the mechanism of phenolics toxicity on living system. • Metabolic pathway and co-metabolic degradation of were outlined. • Aerobic granular sludge for treatment of recalcitrant wastewater was addressed. • Applicability of integrated bioreactors for phenolics degradation was explored. • Biodegradation of phenolics by photosynthetic bacteria and resource recovery.

Biodegradation of Phenol by Unacclimated and Phenol-acclimated Activated Sludge: Effects of Operational Factors on Biodegradation Efficiency and Kinetics

The reaction kinetics for phenol biodegradation at low substrate concentrations can be estimated based on the analysis of changes in the dissolved oxygen concentration in the bulk liquid during biodegradation. The measured oxygen concentration changes with an interesting behavior as biodegradation proceeds. The oxygen concentration in the bulk liquid decreases rapidly in the early stages of degradation and subsequently decreases linearly and then rapidly recovers to the initial saturated level. Taking into account the oxygen transfer rate between gas and liquid phases and oxygen consumption rate by microbes, the change in the dissolved oxygen concentration can be simulated with an unsteady state mass balance equation and three kinetic models for the rate of phenol metabolism: a substrate-inhibited model; a zero-order model; and a combined model. In the combined model, it is assumed that, at phenol concentrations above 10 mg/L, the degradation rate is expressed by a substrate-inhibited model; whereas at concentrations below 10 mg/L the zero-order model is applied. It was found that the characteristics of the change in the dissolved oxygen concentration, especially the rapid increase at the end of degradation, can only be described by the combined kinetic model. This result suggests that conventional Haldane-type kinetics would be unsuitable for estimating the phenol consumption rate at low phenol concentrations, in particular, at concentrations less than 10 mg/L.