A model of the transient kinetics of laccase-catalyzed oxidation of phenol at micromolar concentrations

Rangelov, Stoyan; Nicell, Jim A.

doi:10.1016/j.bej.2015.02.034

Cited by 18 publications

(31 citation statements)

References 88 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, free laccase showed its maximal activity at pH 5 and gradually lost its properties with pH changes (data not presented). These results show that the stability of the laccase after immobilization against pH conditions was improved, mainly due to the protection of the enzyme by the support material [41]. These results stay in agreement with the data presented by Rangelov and Nicell.…”

Section: Effect Of Ph Of Dyes Solution On Removal Efficienciessupporting

confidence: 92%

Synergistic Degradation of Dye Wastewaters Using Binary or Ternary Oxide Systems with Immobilized Laccase

et al. 2018

View full text Add to dashboard Cite

In recent years, groundwater contamination caused by dyes has become an important problem. They enter into wastewater as a result of the textile, automotive, or cosmetics industries. For this reason, new methods are being sought, which would aid at the removal of dye impurities with high efficiency and also would be relatively cheap. In the presented study synthesized TiO2-ZrO2 (with TiO2:ZrO2 molar ratio of 8:2) and TiO2-ZrO2-SiO2 (with TiO2:ZrO2:SiO2 molar ratio of 8:1:1) oxide materials were used as supports for enzyme immobilization. Effective synthesis of the carriers was confirmed by results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), low-temperature nitrogen sorption and Fourier transform infrared spectroscopy (FTIR). The materials achieve high immobilization efficiency of the laccases from Trametes versicolor (83% and 96% for TiO2-ZrO2-laccase and TiO2-ZrO2-SiO2-laccase, respectively). The effect of selected dye concentrations, pH, temperature, and reusability were also tested. The obtained results showed that after removal of textile dyes, such as Alizarin Red S (ARS), Remazol Brilliant Blue R (RBBR), and Reactive Black 5 (RB5), under optimal process conditions, which were pH 5 and 25 °C, from dye solution of 5 mg/L degradation efficiency reached 100%, 91%, and 77%, respectively, suggesting synergistic mechanism of degradation by simultaneous sorption and catalytic action. Finally, reduction of chemical oxygen demand (COD) of the solution after treatment indicated lower mixture toxicity and effective dye degradation.

show abstract

Section: Effect Of Ph Of Dyes Solution On Removal Efficienciessupporting

confidence: 92%

Synergistic Degradation of Dye Wastewaters Using Binary or Ternary Oxide Systems with Immobilized Laccase

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Among these organic pollutants, phenol is well known for its high toxicity in humans and animals (Rangelov and Nicell 2015, Hou et al 2014a, Xu et al 2014. Phenolic pollutants can originate from agricultural and industrial activities, including the partial degradation of phenoxy herbicides, the use of wood preservatives, the generation of wastes by pulp and paper, petrochemicals, dyeing, and other organic chemical and textile industries.…”

Section: Introductionmentioning

confidence: 99%

Characterization and immobilization ofTrametes versicolorlaccase on magnetic chitosan–clay composite beads for phenol removal

Aydemir

Güler

2015

Artificial Cells, Nanomedicine, and Biotechnology

View full text Add to dashboard Cite

Laccase from Trametes versicolor was immobilized on magnetic chitosan-clay composite beads by glutaraldehyde crosslinking. The physical, chemical, and biochemical properties of the immobilized laccase and its application in phenol removal were comprehensively investigated. The structure and morphology of the composite beads were characterized by SEM, TGA, and FTIR analyses. The immobilized laccase showed better storage stability and higher tolerance to the changes in pH and temperature compared with free laccase. Moreover, the immobilized laccase retained more than 75% of its original activity after 10 cycles. The efficiency of phenol removal by immobilized laccase was about 80% under the optimum conditions after 4 h.

show abstract

“…One approach to evaluating the feasibility of using enzymes to oxidize various contaminants at realistic wastewater concentrations was reported recently [5,6]. Specifically, a model was developed that accurately predicted the transient kinetics of the laccase-catalyzed oxidation of aqueous phenolic substrates at concentrations in the micromolar to sub-micromolar range [5,6]. This model was designed to predict the time course of the enzymatic oxidation of a substrate while accounting for the effects of unproductive side reactions and enzyme inactivation.…”

Section: Introductionmentioning

confidence: 99%

“…When the model was applied to four different substrates, including phenol (P), 4-cumylphenol (CP), triclosan (TCL), and estradiol (E2), predictions of substrate concentration as a function of time proved to be very accurate over several orders of magnitude of substrate and laccase concentrations and over prolonged reaction periods. The model was then used to demonstrate that substantial conversion (i.e., 90% to 99.9%) of estradiol, cumylphenol, and triclosan could be achieved for initial substrate concentrations in the micromolar and sub-micromolar range using pragmatic reaction times and laccase concentrations [5,6]. This is in contrast to phenol, a slow substrate of laccase, which was shown not to be practically amenable to substantial oxidation in the same concentration range [5].…”

Section: Introductionmentioning

confidence: 99%

“…The model was then used to demonstrate that substantial conversion (i.e., 90% to 99.9%) of estradiol, cumylphenol, and triclosan could be achieved for initial substrate concentrations in the micromolar and sub-micromolar range using pragmatic reaction times and laccase concentrations [5,6]. This is in contrast to phenol, a slow substrate of laccase, which was shown not to be practically amenable to substantial oxidation in the same concentration range [5]. The utility of the model was demonstrated by showing that it could be used to estimate the quantities of enzyme and the reaction times required to achieve target levels of conversion of individual substrates.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Laccase-Catalyzed Oxidation of Mixed Aqueous Phenolic Substrates at Low Concentrations

Rangelov

Nicell

2019

Catalysts

Self Cite

View full text Add to dashboard Cite

It has been proposed that Trametes versicolor laccase can be used to detoxify wastewaters that are contaminated with phenolic pollutants. However, the oxidation of phenols at low concentrations may be impacted if other substrates tend to interfere with or enhance the oxidation of the target substrate. To test this, experiments were conducted to evaluate effects arising from the simultaneous presence of mixed substrates including phenol (P), estradiol (E2), cumylphenol (CP), and triclosan (TCL), each of which are characterized by different rates of oxidation and tendencies to inactivate laccase. Slower and faster substrates were found to have only minor negative impacts upon the rate of conversion of targeted substrates, except where they tended to cause inactivation. No enhancements in substrate oxidation were observed. A multi-substrate kinetic model was shown to be able to accurately predict the time course of reactions of mixed substrates over extended periods at micromolar and sub-micromolar concentrations, except when estradiol and triclosan were simultaneously present. In this case, more enzyme inactivation was observed than would be expected from the oxidation of individual substrates alone. The utility of the model for providing insights into the reaction phenomenon and for evaluating the feasibility of oxidizing targeted substrates in the presence of other substrates is demonstrated.

show abstract

A model of the transient kinetics of laccase-catalyzed oxidation of phenol at micromolar concentrations

Cited by 18 publications

References 88 publications

Synergistic Degradation of Dye Wastewaters Using Binary or Ternary Oxide Systems with Immobilized Laccase

Synergistic Degradation of Dye Wastewaters Using Binary or Ternary Oxide Systems with Immobilized Laccase

Characterization and immobilization ofTrametes versicolorlaccase on magnetic chitosan–clay composite beads for phenol removal

Laccase-Catalyzed Oxidation of Mixed Aqueous Phenolic Substrates at Low Concentrations

Contact Info

Product

Resources

About