Modelling of phenol biodegradation using mixed microbial cultures and variable initial conditions (original) (raw)
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Modeling the Degradation of Phenol by a mixed microbial culture in a Batch Reactor
Biodegradation of phenol by predominantly Pseudomonas species isolated from a sewage wastewater treatment plant was investigated in batch shake flasks. Phenol with a lower concentration of 100 mg/L was degraded in 10 h and a highest of 800 mg/L in 69 h. The phenol degradation rate was observed to vary largely with the concentrations of phenol used and was found to be less than 10 mg/L/h at both the extremes of the initial concentrations. The degradation kinetics was found follow the three half-order kinetic model with the regression greater than 0.97. The specific substrate utilization rates of the culture at various initial phenol concentrations were fitted to modified substrate inhibition kinetic models of Edward, Haldane, Luong, Han-Levenspiel and Yano-Koga. Among these models the Edward was found to fit the data well with a minimum Root Mean Square error value of 0.0039.
Bioresource technology, 2008
Biodegradation of phenol by a mixed microbial culture, isolated from a sewage treatment plant, was investigated in batch shake flasks. A minimum concentration of 100 and a maximum of 800 mg 1 À1 of phenol in the media were adapted in the degradation study. The phenol degradation rate varied largely and was less than 10 mg l À1 h À1 at both extremes of the initial concentrations in the media. The degradation rate was maximum 15.7 mg l À1 h À1 at 400 mg l À1 phenol. The culture followed substrate inhibition kinetics and the specific growth rate were fitted to Haldane and Han-Levenspiel models. Between the two models the Han-Levenspiel was found to be a better fit with a root mean square error of 0.0211. The biokinetics constants estimated using these models showed good potential of the mixed microbial culture in phenol degradation.
International journal of water resources and environmental engineering, 2010
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 (K s , K i , S m , µ µ µ µ max , Y X/S , k d) estimated using these models showed good potential of the mixed microbial culture in phenol biodegradation.
Two-step modeling of the biodegradation of phenol by an acclimated activated sludge
Chemical Engineering …, 2006
Phenol biodegradation by an acclimated activated sludge was investigated in batch cultures with variable initial conditions of substrate and biomass (0.10 ≤ S 0 /X 0 ≤ 1 g phenol g TSS −1 ). As conventional Haldane model could not explain the biomass growth observed after phenol exhaustion, a model based on the production and later consumption of an inhibitory metabolic intermediate was developed to describe the phenol biodegradation and the biomass growth profiles. This two-step model considers that biodegradation is accomplished by two microbial populations constituting the whole biomass. The new model depicts successfully both biomass and phenol courses by using a single set of kinetic parameters, and support the notion that the production of metabolic intermediates has a determinant role in phenol biodegradation kinetics.
Phenol degradation kinetics of an aerobic mixed culture
Biochemical Engineering Journal, 2009
Biodegradation of 0.25-7.0 mmol l −1 phenol with a mixed bacterial consortium at a temperature of 25 ± 2 • C and a pH of 7.2 was studied in batch aerobic reactors. Substrate inhibition was calculated from experimental growth parameters using the Haldane equation. Kinetic parameters were derived by nonlinear regression with a correlation factor (R 2) of 0.987. The values for Haldane constants max , K s and K i were 0.3095 h −1 , 0.7933 mmol l −1 and 6.887 mmol l −1 , respectively. The value of K i is one of the highest values obtained for mixed cultures degrading phenol under batch conditions. The yield factor (units A 578 mmol −1 phenol) ranged from 0.10 to 0.16. The biokinetic parameters were used to predict the biodegradation profile, which agreed well with the experimental data. The results obtained from this study could be useful for an estimation of the relationship between growth rate and substrate utilization, which may be used to evaluate mass balance for a phenol containing wastewater treatment system involving mixed culture as the "biocatalysts".
Biodegradation of phenol by a mixed microbial culture, isolated from a sewage treatment plant, was investigated in batch shake flasks. A minimum concentration of 100 and a maximum of 800 mg 1 À1 of phenol in the media were adapted in the degradation study. The phenol degradation rate varied largely and was less than 10 mg l À1 h À1 at both extremes of the initial concentrations in the media. The degradation rate was maximum 15.7 mg l À1 h À1 at 400 mg l À1 phenol. The culture followed substrate inhibition kinetics and the specific growth rate were fitted to Haldane and Han-Levenspiel models. Between the two models the Han-Levenspiel was found to be a better fit with a root mean square error of 0.0211. The biokinetics constants estimated using these models showed good potential of the mixed microbial culture in phenol degradation.
Review on Advances in Biodegradation of Phenols: Kinetics, Modelling and Mass Transfer
International journal of research - granthaalayah, 2023
Harmful pollutants like phenol and its derivatives are found in wastewater from a wide range of industries, including oil refining, medicines, coal conversion, chemistry, and petrochemistry. The high concentration, high toxicity, and difficult-to-degrade characteristics of phenols in wastewater pose a serious threat to the environment and to human health. By employing different strains of microorganisms and biocatalysts to create biodegradation procedures of diverse pollutants and a wide spectrum of hazardous compounds, biotechnology has successfully addressed significant environmental challenges. Among various phenols removal techniques, biodegradation is both economical and environmentally friendly. During the study of microbial degradation processes, there is a great deal of interest in the potential for mathematical modelling to forecast microbial growth and degrade harmful or inhibiting environmental pollutants at variable quantities. Such mathematical models are frequently created using aromatic compounds like phenol. The review discusses the following topics: kinetics, modelling, and mass transfer; future scope and directions; diverse microorganisms, bioreactors, the metabolic pathway of phenol, influencing factors, and recent advancements in biological therapy.
Stability and response analyses of phenol degrading biochemical systems
Indian Journal of Chemical Technology, 2009
Chemical systems having non-linear dynamic state equation exhibit unusual behaviour like multiplicity, sustained oscillations etc., when perturbation in any forcing function is somehow introduced to an existing steady state. Under this situation a reacting system may exhibit one or more ambiguous steady states. Biochemical systems using microorganisms following either substrate-or product-inhibited growth kinetics are usually characterized with this type of behaviour. In the present investigation biodegradation of phenol using Pseudomonas putida following substrate inhibited growth kinetics has been taken as model system. The system has been studied in a 2 dm 3 B. Braun fermenter in batch and continuous modes of operation separately. Using the experimental data obtained in batch mode of operation the kinetic parameters of the systems have been determined considering substrate inhibited Haldane type kinetics for biodegradation of phenol. Two separate techniques, viz., linear stability analysis and phase plane analysis have been performed to study the characteristics of steady states from local and global points of view respectively. Response analysis of the system has been performed using step-type perturbations in inlet substrate concentrations of different amplitudes. The experimental findings show good agreement with the simulated results.
Archives of Microbiology, 2022
One of the main organic pollutants that could result from industrial products and chemical transformations is phenol. In the current study, the kinetics of Serratia odorifera, which was isolated from arable soil, was studied by growing it on broth minimal medium spiked with phenol as only carbon source and energy. The newly isolated plant growth-promoting bacterium (PGPB), S. odorifera, was used for the first time for phenol biodegradation. The growth kinetics parameters (phenoldependent) including maximum specific growth rate (μmax), half-saturation coefficient (Ks), and the Haldane's growth kinetics inhibition coefficient (Ki), were tested via Haldane inhibition model and resulted on the 0.469 (h −1), 26.6 (mgL −1), and 292 (mgL −1), respectively. The sum of squared error (SSR) of 4.89 × 10-3 was fitted to the experimental data by Haldane equation. The results of phenol biodegradation were fitted into the modified Gombertz model. The increase of phenol concentrations led to increases in both the rate of phenol biodegradation and lagging time. The optimal phenol biodegradation and bacterial growth obtained by S. odorifera, were at 28 °C incubation temperature and a pH of 7.0. The pathway of phenol biodegradation by S. odorifera was proposed in the current study to provide a new insight into synchronization of phenol biodegradation and plant growth-promoting bacteria. This may play an important role in remediation of phenol-contaminated soil besides promoting the plant growth, thus lessening the plant stress.
Kinetic Parameters of Phenol Biodegradation with Different Microorganisms: A Review
Most industries release wastewater contains high concentrations of phenol which is toxic and contaminating the environment. Biological treatments are preferable for the phenolic compounds treatment. This review aims to investigate the impacts of temperatures, pH, and concentration of substrate on the phenolic compounds biodegradation, to compare the kinetic parameters of different microorganisms, and to discuss the different between the kinetic parameters of aerobic and anaerobic treatment. The review showed that most of the phenol biodegrading bacteria are P. Putida species and mixed cultures but P. Putida has a better adaptation to phenol biodegradation. The values of µ max and K s in anaerobic process are smaller than the values attained in aerobic process. The optimum temperature to acclimatize bacteria to the phenol substrate is 30 ºC while the optimum pH condition is between 6.5 and 7.5. As the phenol concentration was increased, there was an increase in the values of the Ks and even when concentration is low; phenols have a significant inhibitory impact on (μ). The values of Ki for phenol degradation for P. putida species were higher than the values of Ki of mixed cultures. The highest Ki value for the phenol degrading among P.Putida species was 1185.8 mg/L and the highest Ki value among mixed cultures was 648.1 mg/L and the highest Ki value among the other species was 2434.7 mg/L.