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Organochlorides and particularly chlorophenols are environmental pollutants that deserve special attention. Enzymatic membrane bioreactors may be alternatives for efficiently removing such hazardous organochlorides from aqueous solutions. We propose here a novel enzymatic membrane bioreactor comprising an ultrafiltration membrane GR81PP, electrospun fibers made of cellulose acetate, and laccase immobilized using an incubation and a fouling approach. Configurations of this biosystem exhibiting the highest catalytic activity were selected for removal of 2-chlorophenol and 4-chlorophenol from aqueous solution in an enzymatic membrane bioreactor under various process conditions. The highest removal of chlorophenols, at 88% and 74% for 2-chlorophenol and 4-chlorophenol, respectively, occurred at pH 5 and 30 °C in the GR81PP/cellulose acetate/laccase biosystem with enzyme immobilized by the fouling method. Furthermore, the GR81PP/cellulose acetate/laccase biosystem with enzyme immobilized by the fouling method exhibited significant reusability and storage stability compared with the biosystem with laccase immobilized by the incubation method. The mechanism of enzyme immobilization is based on pore blocking and cake-layer formation, while the mechanism of chlorophenols removal was identified as a synergistic combination of membrane separation and enzymatic conversion. The importance of the conducted research is due to efficient removal of hazardous organochlorides using a novel enzymatic membrane bioreactor. The study demonstrates the biosystem's high catalytic activity, reusability, and stability, offering a promising solution for environmental pollution control.
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Reactores Biológicos , Clorofenoles , Lacasa , Membranas Artificiales , Contaminantes Químicos del Agua , Clorofenoles/química , Lacasa/metabolismo , Lacasa/química , Contaminantes Químicos del Agua/química , Enzimas Inmovilizadas/química , Celulosa/química , Purificación del Agua/métodosRESUMEN
Biochar has emerged as an efficacious green material for remediation of a wide spectrum of environmental pollutants. Biochar has excellent characteristics and can be used to reduce the bioavailability and leachability of emerging pollutants in soil through adsorption and other physico-chemical reactions. This paper systematically reviewed previous researches on application of biochar/engineered biochar for removal of soil contaminants, and underlying adsorption mechanism. Engineered biochar are derivatives of pristine biochar that are modified by various physico-chemical and biological procedures to improve their adsorption capacities for contaminants. This review will promote the possibility to expand the application of biochar for restoration of degraded lands in the industrial area or saline soil, and further increase the useable area. This review shows that application of biochar is a win-win strategy for recycling and utilization of waste biomass and environmental remediation. Application of biochar for remediation of contaminated soils may provide a new solution to the problem of soil pollution. However, these studies were performed mainly in a laboratory or a small scale, hence, further investigations are required to fill the research gaps and to check real-time applicability of engineered biochar on the industrial contaminated sites for its large-scale application.
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Carbón Orgánico , Restauración y Remediación Ambiental , Contaminantes del Suelo , Suelo , Carbón Orgánico/química , Contaminantes del Suelo/química , Contaminantes del Suelo/análisis , Restauración y Remediación Ambiental/métodos , Suelo/química , AdsorciónRESUMEN
In the presented study, a variety of hybrid and single nanomaterials of various origins were tested as novel platforms for horseradish peroxidase immobilization. A thorough characterization was performed to establish the suitability of the support materials for immobilization, as well as the activity and stability retention of the biocatalysts, which were analyzed and discussed. The physicochemical characterization of the obtained systems proved successful enzyme deposition on all the presented materials. The immobilization of horseradish peroxidase on all the tested supports occurred with an efficiency above 70%. However, for multi-walled carbon nanotubes and hybrids made of chitosan, magnetic nanoparticles, and selenium ions, it reached up to 90%. For these materials, the immobilization yield exceeded 80%, resulting in high amounts of immobilized enzymes. The produced system showed the same optimal pH and temperature conditions as free enzymes; however, over a wider range of conditions, the immobilized enzymes showed activity of over 50%. Finally, a reusability study and storage stability tests showed that horseradish peroxidase immobilized on a hybrid made of chitosan, magnetic nanoparticles, and selenium ions retained around 80% of its initial activity after 10 repeated catalytic cycles and after 20 days of storage. Of all the tested materials, the most favorable for immobilization was the above-mentioned chitosan-based hybrid material. The selenium additive present in the discussed material gives it supplementary properties that increase the immobilization yield of the enzyme and improve enzyme stability. The obtained results confirm the applicability of these nanomaterials as useful platforms for enzyme immobilization in the contemplation of the structural stability of an enzyme and the high catalytic activity of fabricated biocatalysts.
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Quitosano , Nanotubos de Carbono , Selenio , Enzimas Inmovilizadas/química , Peroxidasa de Rábano Silvestre/química , Quitosano/química , Estabilidad de Enzimas , Iones , Concentración de Iones de HidrógenoRESUMEN
A wide array of organic compounds have been recognized as pollutants of high concern due to their controlled or uncontrolled presence in environmental matrices. The persistent prevalence of diverse organic pollutants, including pharmaceutical compounds, phenolic compounds, synthetic dyes, and other hazardous substances, necessitates robust measures for their practical and sustainable removal from water bodies. Several bioremediation and biodegradation methods have been invented and deployed, with a wide range of materials well-suited for diverse environments. Enzyme-linked carbon-based materials have been considered efficient biocatalytic platforms for the remediation of complex organic pollutants, mostly showing over 80% removal efficiency of micropollutants. The advantages of enzyme-linked carbon nanotubes (CNTs) in enzyme immobilization and improved catalytic potential may thus be advantageous for environmental research considering the current need for pollutant removal. This review outlines the perspective of current remediation approaches and highlights the advantageous features of enzyme-linked CNTs in the removal of pollutants, emphasizing their reusability and stability aspects. Furthermore, different applications of enzyme-linked CNTs in environmental research with concluding remarks and future outlooks have been highlighted. Enzyme-linked CNTs serve as a robust biocatalytic platform for the sustainability agenda with the aim of keeping the environment clean and safe from a variety of organic pollutants.
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Contaminantes Ambientales , Nanotubos de Carbono , Contaminantes Ambientales/metabolismo , Biodegradación Ambiental , Catálisis , Sustancias PeligrosasRESUMEN
This study reports a biocatalytic system of immobilized laccase and 3D printed open-structure biopolymer scaffoldings. The scaffoldings were computer-designed and 3D printed using polylactide (PLA) filament. The immobilization of laccase onto the 3D printed PLA scaffolds were optimized with regard to pH, enzyme concentration, and immobilization time. Laccase immobilization resulted in a small reduction in reactivity (in terms of Michaelis constant and maximum reaction rate) but led to significant improvement in chemical and thermal stability. After 20 days of storage, the immobilized and free laccase showed 80% and 35% retention of the initial enzymatic activity, respectively. The immobilized laccase on 3D printed PLA scaffolds achieved 10% improvement in the removal of estrogens from real wastewater as compared to free laccase and showed the significant reusability potential. Results here are promising but also highlight the need for further study to improve enzymatic activity and reusability.
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Enzimas Inmovilizadas , Aguas Residuales , Estabilidad de Enzimas , Enzimas Inmovilizadas/metabolismo , Lacasa/metabolismo , Poliésteres , Impresión Tridimensional , Concentración de Iones de HidrógenoRESUMEN
The synergistic combination of current biotechnological and nanotechnological research has turned to multienzyme co-immobilization as a promising concept to design biocatalysis engineering. It has also intensified the development and deployment of multipurpose biocatalysts, for instance, multienzyme co-immobilized constructs, via biocatalysis/protein engineering to scale-up and fulfil the ever-increasing industrial demands. Considering the characteristic features of both the loaded multienzymes and nanostructure carriers, i.e., selectivity, specificity, stability, resistivity, induce activity, reaction efficacy, multi-usability, high catalytic turnover, optimal yield, ease in recovery, and cost-effectiveness, multienzyme-based green biocatalysts have become a powerful norm in biocatalysis/protein engineering sectors. In this context, the current state-of-the-art in enzyme engineering with a synergistic combination of nanotechnology, at large, and nanomaterials, in particular, are significantly contributing and providing robust tools to engineer and/or tailor enzymes to fulfil the growing catalytic and contemporary industrial needs. Considering the above critics and unique structural, physicochemical, and functional attributes, herein, we spotlight important aspects spanning across prospective nano-carriers for multienzyme co-immobilization. Further, this work comprehensively discuss the current advances in deploying multienzyme-based cascade reactions in numerous sectors, including environmental remediation and protection, drug delivery systems (DDS), biofuel cells development and energy production, bio-electroanalytical devices (biosensors), therapeutical, nutraceutical, cosmeceutical, and pharmaceutical oriented applications. In conclusion, the continuous developments in nano-assembling the multienzyme loaded co-immobilized nanostructure carriers would be a unique way that could act as a core of modern biotechnological research.
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Enzimas Inmovilizadas , Nanoestructuras , Enzimas Inmovilizadas/química , Estudios Prospectivos , Biotecnología , Nanoestructuras/química , Ingeniería de ProteínasRESUMEN
Due to the growing importance of synthesizing active pharmaceutical ingredients (APIs) in enantiomerically pure form, new methods of asymmetric synthesis are being sought. Biocatalysis is a promising technique that can lead to enantiomerically pure products. In this study, lipase from Pseudomonas fluorescens, immobilized on modified silica nanoparticles, was used for the kinetic resolution (via transesterification) of a racemic mixture of 3-hydroxy-3-phenylpropanonitrile (3H3P), where the obtaining of a pure (S)-enantiomer of 3H3P is a crucial step in the fluoxetine synthesis pathway. For additional stabilization of the enzyme and enhanced process efficiency, ionic liquids (ILs) were used. It was found that the most suitable IL was [BMIM]Cl; a process efficiency of 97.4 % and an enantiomeric excess (ee%) of 79.5 % were obtained when 1 % (w/v) of that IL in hexane was applied and the process was catalyzed by lipase immobilized on amine-modified silica.
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Nanobiocatalysts, in which enzyme molecules are integrated into/onto multifunctional materials, such as metal-organic frameworks (MOFs), have been fascinating and appeared as a new interface of nanobiocatalysis with multi-oriented applications. Among various nano-support matrices, functionalized MOFs with magnetic attributes have gained supreme interest as versatile nano-biocatalytic systems for organic bio-transformations. From the design (fabrication) to deployment (application), magnetic MOFs have manifested notable efficacy in manipulating the enzyme microenvironment for robust biocatalysis and thus assure requisite applications in several areas of enzyme engineering at large and nano-biocatalytic transformations, in particular. Magnetic MOFs-linked enzyme-based nano-biocatalytic systems offer chemo-regio- and stereo-selectivities, specificities, and resistivities under fine-tuned enzyme microenvironments. Considering the current sustainable bioprocesses demands and green chemistry needs, we reviewed synthesis chemistry and application prospects of magnetic MOFs-immobilized enzyme-based nano-biocatalytic systems for exploitability in different industrial and biotechnological sectors. More specifically, following a thorough introductory background, the first half of the review discusses various approaches to effectively developed magnetic MOFs. The second half mainly focuses on MOFs-assisted biocatalytic transformation applications, including biodegradation of phenolic compounds, removal of endocrine disrupting compounds, dye decolorization, green biosynthesis of sweeteners, biodiesel production, detection of herbicides and screening of ligands and inhibitors.
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Enzimas Inmovilizadas , Estructuras Metalorgánicas , Enzimas Inmovilizadas/química , Biocatálisis , Estructuras Metalorgánicas/química , Biotecnología , Fenómenos MagnéticosRESUMEN
With robust catalytic features, manganese peroxidases (MnPs) from various sources, including fungi and bacteria, have gained much consideration in many biotechnological applications with particular emphasis on environmental remediation. MnP is a heme-containing enzyme that belongs to the oxidoreductases that can catalyze the degradation of various organic pollutants, such as chlorophenols, nitroaromatic compounds, industrial dyes, and polycyclic aromatic hydrocarbons. To spotlight the MnP as biocatalytic tool, an effort has been put forward to cover the four major compartments. For instance, following a brief introduction, first, various microbial sources of MnP are discussed with examples. Second, structural attributes and biocatalytic features of MnP are given with examples. Third, different MnP immobilization strategies, including adsorption, covalent linking, entrapment, and cross-linking, are discussed with a significant motive to strengthen the enzyme's stability against diverse deactivation agents by restricting the conformational mobility of molecules. Compared to free counterparts, immobilized MnP fractions perform well in hostile environments. Finally, various biotechnological applications, such as fuel ethanol production, de-lignification, textile industry, pulp and paper industry, degradation of phenolic and non-phenolic compounds, and pharmaceutical and pesticide degradation, are briefly discussed.
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Enzimas Inmovilizadas , Manganeso , Manganeso/metabolismo , Enzimas Inmovilizadas/química , Peroxidasas/metabolismo , Biotecnología , Hongos/metabolismoRESUMEN
Nowadays, the specificity of enzymatic processes makes them more and more important every year, and their usage on an industrial scale seems to be necessary. Enzymatic cofactors, however, play a crucial part in the prospective applications of enzymes, because they are indispensable for conducting highly effective biocatalytic activities. Due to the relatively high cost of these compounds and their consumption during the processes carried out, it has become crucial to develop systems for cofactor regeneration. Therefore, in this review, an attempt was made to summarize current knowledge on enzymatic regeneration methods, which are characterized by high specificity, non-toxicity and reported to be highly efficient. The regeneration of cofactors, such as nicotinamide dinucleotides, coenzyme A, adenosine 5'-triphosphate and flavin nucleotides, which are necessary for the proper functioning of a large number of enzymes, is discussed, as well as potential directions for further development of these systems are highlighted. This review discusses a range of highly effective cofactor regeneration systems along with the productive synthesis of many useful chemicals, including the simultaneous renewal of several cofactors at the same time. Additionally, the impact of the enzyme immobilization process on improving the stability and the potential for multiple uses of the developed cofactor regeneration systems was also presented. Moreover, an attempt was made to emphasize the importance of the presented research, as well as the identification of research gaps, which mainly result from the lack of available literature on this topic.
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Coenzimas , Niacinamida , Coenzimas/química , Enzimas Inmovilizadas/metabolismo , Biocatálisis , Adenosina TrifosfatoRESUMEN
Photocatalytic degradation is one of the most promising technologies available for removing a variety of synthetic and organic pollutants from the environmental matrices because of its high catalytic activity, reduced energy consumption, and low total cost. Due to its acceptable bandgap, broad light-harvesting efficiency, significant renewability, and stability, Fe2O3 has emerged as a fascinating material for the degradation of organic contaminants as well as numerous dyes. This study thoroughly reviewed the efficiency of Fe2O3-based nanocomposite and nanomaterials for water remediation. Iron oxide structure and various synthetic methods are briefly discussed. Additionally, the electrocatalytic application of Fe2O3-based nanocomposites, including oxygen evolution reaction, oxygen reduction reaction, hydrogen evolution reaction, and overall water splitting efficiency, was also highlighted to illustrate the great promise of these composites. Finally, the ongoing issues and future prospects are directed to fully reveal the standards of Fe2O3-based catalysts. This review is intended to disseminate knowledge for further research on the possible applications of Fe2O3 as a photocatalyst and electrocatalyst.
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Nanocompuestos , Purificación del Agua , Purificación del Agua/métodos , Nanocompuestos/química , Catálisis , Metales , OxígenoRESUMEN
Nanozymes are super-efficient nanomaterials with enzyme-like characteristics, as the name suggests. In the last decade, efforts have been made to develop "artificial enzymes," which are alternatives to natural enzymes. As nanoscience and nanotechnology advance, nanozymes, which are catalytic nanomaterials having enzyme-like properties, have fascinated researchers' attention. Nanozymes with unique physicochemical properties and nanomaterials that mimic catalytic activity have gained a special interest in the industrial sectors. However, several constraints have hampered their effective deployment in industrial processes, including denaturation, time-consuming manufacturing, overall high cost-ratio, and reutilization challenges. After a brief overview of nanozyme research, an analysis of the similarities and differences between nanozymes and natural and synthetic enzymes is presented. Because of their distinct properties, nanozymes stand out in this comparison. Nanozymes have exhibited a variety of applications leveraging the physiochemical properties of nanomaterials, ranging from in vitro detection to enzyme substitution in biological systems. In addition, nanozymes have introduced a new field called nanozymology, which blends nanotechnology with enzymology.
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Nanoestructuras , Catálisis , Nanoestructuras/química , NanotecnologíaRESUMEN
In present study, we describe the biodegradation of direct blue (DB) 297 and reactive blue (RB) 221 by immobilizing horseradish peroxidase (HRP) isolated from fresh leaves of Moringa Oliefera on iron oxide nanoparticles. Iron oxide nanoparticles were synthesized by co-precipitation method and showed a maximum immobilization efficiency of 87%. The surface topography of iron oxide nanoparticles was envisaged by scanning electron microscopy (SEM), results showed that magnetic nanoparticles (MNPs) were in the form of aggregates having size of 1 µm. Furthermore, immobilization was confirmed via functional group identification performed by Fourier transformed infrared spectroscopy (FTIR). Immobilization phenomena displaced the optimum temperature from 35 °C to 50 °C moreover, pH optima were altered from 5.0 to 7.0. Vmax and Km for free and immobilized HRP, were 303 U/mg and 1.66 mM and 312 U/mg and 1.94 mM, respectively. Enzymatic thermodynamic measurements (ΔH*, ΔS*, Ea, ΔG*) were also evaluated for immobilized HRP and its free counterpart. Optimum degradation of reactive blue (RB) and direct blue (DB) 297 with free and immobilized HRP was observed at pH 5 and at temperature 40 °C respectively. The removal efficiency of DB 297 and RB 221 with free HRP was 75% and 86% while with immobilized HRP was 81% and 92% respectively. Furthermore, biodegradation of reactive blue (RB) 221 and direct blue (DB) 297 with immobilized and free biocatalyst was also investigated by Fourier transform infrared spectroscopy (FTIR) by identification of groups involved in dye degradation. FTIR results confirmed the 100% degradation of dyes. Immobilized HRP retained significant catalytic activity after five consecutive cycles of dye degradation. In conclusion, Fe3O4 nanoparticles are promising and environmentally friendly media for enzyme immobilization. Moreover, immobilized HRP showed more thermal stability, pH stability and higher dye degradation efficiency as compared to free HRP. Furthermore, the immobilized HRP, economically more convenient and easily removable from reaction media. Owing to its thermal stability, ease of separation from reaction media and reusability, the magnetically separatable immobilized HRP can be exploited successfully for treatment of dye contaminated textile effluents.
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Colorantes , Enzimas Inmovilizadas , Biocatálisis , Colorantes/química , Estabilidad de Enzimas , Enzimas Inmovilizadas/química , Peroxidasa de Rábano Silvestre/metabolismo , Concentración de Iones de Hidrógeno , Nanopartículas Magnéticas de Óxido de Hierro , Temperatura , TermodinámicaRESUMEN
In recent decades, enzyme-based biocatalytic systems have garnered increasing interest in industrial and applied research for catalysis and organic chemistry. Many enzymatic reactions have been applied to sustainable and environmentally friendly production processes, particularly in the pharmaceutical, fine chemicals, and flavor/fragrance industries. However, only a fraction of the enzymes available has been stepped up towards industrial-scale manufacturing due to low enzyme stability and challenging separation, recovery, and reusability. In this context, immobilization and co-immobilization in robust support materials have emerged as valuable strategies to overcome these inadequacies by facilitating repeated or continuous batch operations and downstream processes. To further reduce separations, it can be advantageous to use multiple enzymes at once in one pot. Enzyme co-immobilization enables biocatalytic synergism and reusability, boosting process efficiency and cost-effectiveness. Several studies on multi-enzyme immobilization and co-localization propose kinetic advantages of the enhanced turnover number for multiple enzymes. This review spotlights recent progress in developing versatile biocatalytic cascade systems by multi-enzyme co-immobilization on environmentally friendly biopolymers and nanostructured materials and their application scope in the chemical and biotechnological industries. After a succinct overview of carrier-based and carrier-free immobilization/co-immobilizations, co-immobilization of enzymes on a range of biopolymer and nanomaterials-based supports is thoroughly compiled with contemporary and state-of-the-art examples. This study provides a new horizon in developing effective and innovative multi-enzymatic systems with new possibilities to fully harness the adventure of biocatalytic systems.
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Enzimas Inmovilizadas , Nanoestructuras , Enzimas Inmovilizadas/metabolismo , Biocatálisis , Biopolímeros , Estabilidad de EnzimasRESUMEN
Nanostructured materials offer a significant role in wastewater treatment with diminished capital and operational expense, low dose, and pollutant selectivity. Specifically, the nanocomposites of cellulose with inorganic nanoparticles (NPs) have drawn a prodigious interest because of the extraordinary cellulose properties, high specific surface area, and pollutant selectivity of NPs. Integrating inorganic NPs with cellulose biopolymers for wastewater treatment is a promising advantage for inorganic NPs, such as colloidal stability, agglomeration prevention, and easy isolation of magnetic material after use. This article presents a comprehensive overview of water treatment approaches following wastewater remediation by green and environmentally friendly cellulose/inorganic nanoparticles-based bio-nanocomposites. The functionalization of cellulose, functionalization mechanism, and engineered hybrid materials were thoroughly discussed. Moreover, we also highlighted the purification of wastewater through the composites of cellulose/inorganic nanoparticles via adsorption, photocatalytic and antibacterial approach.
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Contaminantes Ambientales , Nanocompuestos , Nanopartículas , Contaminantes Químicos del Agua , Purificación del Agua , Aguas Residuales , CelulosaRESUMEN
The development of efficient strategies for wastewater treatment to remove micropollutants is of the highest importance. Hence, in this study, we presented a rapid approach to the production of biocatalytic membranes based on commercially available cellulose membrane and oxidoreductase enzymes including laccase, tyrosinase, and horseradish peroxidase. Effective enzyme deposition was confirmed based on Fourier transform infrared spectra, whereas results of spectrophotometric measurements showed that immobilization yield for all proposed systems exceeded 80% followed by over 80% activity recovery, with the highest values (over 90%) noticed for the membrane-laccase system. Further, storage stability and reusability of the immobilized enzyme were improved, reaching over 75% after, respectively, 20 days of storage, and 10 repeated biocatalytic cycles. The key stage of the study concerned the use of produced membranes for the removal of hematoporphyrin, (2,4-dichlorophenoxy)acetic acid (2,4-D), 17α-ethynylestradiol, tetracycline, tert-amyl alcohol (anesthetic drug), and ketoprofen methyl ester from real wastewater sampling at various places in the wastewater treatment plant. Although produced membranes showed mixed removal rates, all of the analyzed compounds were at least partially removed from the wastewater. Obtained data clearly showed, however, that composition of the wastewater matrix, type of pollutants as well as type of enzyme strongly affect the efficiency of enzymatic treatment of wastewater.
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Aguas Residuales , Purificación del Agua , Lacasa/metabolismo , Purificación del Agua/métodos , Enzimas Inmovilizadas/metabolismo , BiocatálisisRESUMEN
Over recent years, silica and silica-based materials have become some of the most frequently used materials worldwide [...].
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In this study, lipase from Aspergillus niger immobilized by physical immobilization by the adsorption interactions and partially interfacial activation and mixed physical immobilization via interfacial activation and ion exchange was used in the kinetic resolution of the ketoprofen racemic mixture. The FTIR spectra of samples after immobilization of enzyme-characteristic signals can be seen, and an increase in particle size diameters upon immobilization is observed, indicating efficient immobilization. The immobilization yield was on the level of 93% and 86% for immobilization unmodified and modified support, respectively, whereas activity recovery reached around 90% for both systems. The highest activity of immobilized biocatalysts was observed at pH 7 and temperature 40 °C and pH 8 and 20 °C for lipase immobilized by physical immobilization by the adsorption interactions and partially interfacial activation and mixed physical immobilization via interfacial activation and ion exchange, respectively. It was also shown that over a wide range of pH (from 7 to 10) and temperature (from 20 to 60 °C) both immobilized lipases retained over 80% of their relative activity, indicating improvement of enzyme stability. The best solvent during kinetic resolution of enantiomers was found to be phosphate buffer at pH 7, which obtained the highest efficiency of racemic ketoprofen methyl ester resolution at the level of over 51%, followed by enantiomeric excess 99.85% in the presence of biocatalyst obtained by physical immobilization by the adsorption interactions and partially interfacial activation.
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Nowadays, the increasing amounts of dyes present in wastewaters and even water bodies is an emerging global problem. In this work we decided to fabricate new biosystems made of nanofiltration or ultrafiltration membranes combined with laccase entrapped between polystyrene electrospun fibers and apply them for decolorization of aqueous solutions of three azo dyes, C.I. Acid Yellow 23 (AY23), C.I. Direct Blue 71 (DB71) and C.I. Reactive Black 5 (RB5). Besides effective decolorization of the permeate stream, the biosystems also allowed removal of dyes from the retentate stream as a result of enzymatic action. The effect of pH and applied pressure on decolorization efficiencies was investigated, and pH 5 and pressure of 2 bar gave the highest removal efficiencies of 97% for AY23 and 100% for both DB71 and RB5 from permeate solutions while decolorization of retentate for RB5 reached 65% under these conditions. Almost 100% decolorization of all dyes was achieved after three consecutive enzyme membrane cycles. Decolorization was shown to be due to the synergistic action of membrane separation and bioconversion. The biocatalytic action also enabled significant reduction of permeate and retentate toxicity, which is one of the biggest environmental health issues for these types of streams.
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Compuestos Azo , Lacasa , Reactores Biológicos , Color , Colorantes , TartrazinaRESUMEN
Enzymatic membrane reactors equipped with multifunctional biocatalytic membranes are promising and sustainable alternatives for removal of micropollutants, including steroid estrogens, under mild conditions. Thus, in this study an effort was made to produce novel multifunctional biocatalytic polyelectrolyte multilayer membranes via polyelectrolyte layer-by-layer assembly with laccase enzyme immobilized between or into polyelectrolyte layers. In this study, multifunctional biocatalytic membranes are considered as systems composed of commercially available filtration membrane modified by polyelectrolytes and immobilized enzymes, which are produced for complex treatment of water pollutants. The multifunctionality of the proposed systems is related to the fact that these membranes are capable of micropollutants removal via simultaneous catalytic conversion, membrane adsorption and membrane rejection making remediation process more complex, however, also more efficient. Briefly, cationic poly-l-lysine and polyethylenimine as well as anionic poly(sodium 4-styrenesulfonate) polyelectrolytes were deposited onto NP010 nanofiltration and UFX5 ultrafiltration membranes to produce systems for removal of 17α-ethynylestradiol. Images from scanning electron microscopy confirm effective enzyme deposition, whereas results of zeta potential measurements indicate introduction of positive charge onto the membranes. Based on preliminary results, four membranes with over 70%, activity retention produced using polyethylenimine in internal and entrapped mode, were selected for degradation tests. Systems based on UFX5 membrane allowed over 60% 17α-ethynylestradiol removal within 100 min, whereas NP010-based systems removed over 75% of estrogen within 150 min. Further, around 80% removal of 17α-ethynylestradiol was possible from the solutions at concentration up to 0.1 mg/L at pH ranging from 4 to 6 and at the pressure up to 3 bar, indicating high activity of the immobilized laccase over wide range of process conditions. Produced systems exhibited also great long-term stability followed by limited enzyme elution from the membrane. Finally, removal of over 70% and 60% of 17α-ethynylestradiol, respectively by NP010 and UFX5 systems after 8 cycles of repeated use indicate high reusability potential of the systems and suggest their practical application in removal of micropollutants, including estrogens.