Copper Alginate Research Articles

One-step synthesis of superparamagnetic copper alginate gel microspheres (Cu2+-Alg@Fe3O4) using a compression nebulizer

For the application needs of histidine-rich protein separation, this study proposes to prepare a magnetic adsorbent enriched with copper ions and small particle size. Using a compression nebulizer, the magnetic + sodium alginate solution was broken into micrometer-sized droplets and cross-linked and cured with copper ion solution. The magnetic copper alginate microspheres (Cu2+-Alg@Fe3O4) were obtained with an average particle size of 7.1 μm, a magnetic saturation intensity of 36.9 emu·g−1, and a Cu2+ content of 149.2 mg·g−1.The adsorption equilibrium time of the Cu2+-Alg@Fe3O4 microspheres on bovine hemoglobin(BHb) was 90 min, and the maximum adsorption amount was 4318.5 mg·g−1. The Cu2+-Alg@Fe3O4 microspheres also showed stable and good adsorption performance in five cyclic adsorption experiments.

Novel Copper Alginate Microspheres as Ecological Fungicides

Phytopathogenic fungi are living organisms that cause plant diseases and great damage to agricultural products. Despite the wide range of commercial fungicide products in use, there is a clear need for new and environmentally friendly fungicides. Here we propose a new ecological fungicide, copper alginate microspheres prepared by ionic gelation. The microspheres were characterized (morphology and topography, encapsulation efficiency, loading capacity, swelling behavior, rheology, kinetics and mechanism of copper ions release) and their in vitro antifungal potential against selected genera of phytopathogenic fungi was evaluated. Copper alginate microspheres inhibited spore germination of Botrytis cinerea. Compared to the control, the inhibition of B. cinerea spore germination (48%) was greater than that of the commercial fungicide Neoram® (22%). The mycelial growth of Cercospora beticola and Phytophthora ramorum was also significantly inhibited by the addition of copper alginate microspheres. Novel fungicide offer effective disease control while minimizing environmental impact and promoting sustainable agriculture practices.

Mechanical-Enhanced and Durable Zwitterionic Hydrogel Coating for Inhibiting Coagulation and Reducing Bacterial Infection.

Blood-contact medical devices are indispensable for clinical interventions, yet their susceptibility to thrombosis and bacterial infections poses substantial risks to treatment efficacy and patient well-being. This study introduces a polysulfobetaine/alginate-CuII (SAC) zwitterionic hydrogel coating on polyurethane (PU) surfaces. This approach retains the superhydrophilic and antifouling nature of pSBMA while conferring the antibacterial effects of copper ions. Meanwhile, the copper alginate network intertwines with the polysulfobetaine (pSBMA) network, enhancing its mechanical properties and overcoming inherent weaknesses, thereby improving coating durability. Compared to the substrate, the SAC hydrogel coating significantly reduces thrombus adhesion mass by approximately 81.5% during extracorporeal blood circulation and effectively prevents bacterial biofilm formation even in a high-concentration bacterial milieu over 30 days. Moreover, the results from an isolated blood circulation model in New Zealand white rabbits affirm the impressive anticoagulant efficacy of the SAC hydrogel coating. The findings suggest that this hydrogel coating and its application method hold promise as a solution for blood-contact material surface modification to address thrombosis and bacterial biofilm formation simultaneously.

Bacterial cellulose/silver composite film in-situ coated copper alginate for thermally responsive antimicrobial dressing

Bacterial cellulose/silver composite film in-situ coated copper alginate for thermally responsive antimicrobial dressing

Insight of multifunctional Cu-alginate hydrogel membrane for precise molecule/ion separation applications

Membrane technology has garnered significant attention for its role in addressing the challenges of molecule/ion separation processes, yet it remains hindered by issues such as membrane fouling, including organic and biofouling. While calcium alginate (CaAlg) membranes have demonstrated remarkable antifouling and molecule/ion separation properties, they suffer from high swell ability and poor mechanical performance. This study introduces a one-step ion-crosslinking method to fabricate a series of copper alginate (CuAlg) hydrogel membranes. These membranes are then assembled into a dual-layer structure with a modified hydrophilic and mechanically robust microfiltration fiber support layer (MHSL). Notably, the CuAlg/MHSL membrane exhibits excellent separation performance, characterized by high selectivity and flux recovery rate. This membrane significantly enhances the long-term molecule/ion separation performance through improved mechanical strength, anti-swelling properties, and antimicrobial capabilities. In addition, the decreased thickness of the CuAlg/MHSL membrane enables higher flux rates, proving beneficial in cases of CaAlg membranes' inability to perform well under high-salt conditions. To further investigate the pore structure and anti-swelling mechanism of the CuAlg membrane, molecular dynamics (MD) simulations are conducted. Additionally, a life cycle analysis comparing the CuAlg hydrogel with various traditional polymers assesses their respective environmental impacts, highlighting the eco-friendliness of the hydrogel as a membrane substrate. These findings provide valuable insights for developing sustainable hydrogel membranes with stable performance and high separation efficiency in molecular/ion separation applications.

Convenient synthesis of seaweed-derived porous carbon supported Cu-MoO2 composite as high-performance photocatalyst

The development of a simple and convenient method for synthesizing photocatalysts for the degradation of tetracycline remains a great challenge. In this work, a Cu-MoO2@C composite was successfully synthesized by a high-temperature carbonization of ammonium molybdate infiltrated copper alginate aerogel, which was obtained by curing a mixture of sodium alginate and ammonium molybdate using Cu2+ ions. The photocatalytic properties of the prepared composites were evaluated by the degradation of tetracycline. The results showed that the introduction of Cu nanoparticles on the MoO2@C hybrid could significantly improve the catalytic performance, and the degradation rate of tetracycline reached 92.48 % after 60 min light exposure. Tetracycline's estimated photodegradation rate constant, which was 0.04013 min−1, was 5 times more than that of the composite without Cu loading. Furthermore, the reaction mechanism was explored by electron spin resonance (ESR) test and free radical capture reagent. Intermediate products of tetracycline degradation were analyzed by liquid mass spectrometry (LC-MS).

Facile one-step synthesis of CuZn-HDS/alginate hydrogel beads for highly efficient and selective removal of methyl orange

Hydroxy double salts (HDSs) have shown enormous potential for removing dyes from wastewater. However, the powder form of HDSs limits their potential in commercial applications. Herein, we proposed a facile one-step route to incorporate CuZn-HDS into the copper alginate matrix for methyl orange removal. This strategy could not only shape CuZn-HDS to beads but also significantly enhance the adsorption ability of the matrix. The obtained composite hydrogel beads displayed high water stability and excellent adsorption performance for MO, with more than 98% of MO being removed by CuZn-HDS/Alg-0.5. The maximum adsorption capacity of CuZn-HDS/Alg-0.5 for MO was 763.3 mg·g−1 at 298 K. Besides, the adsorption process matched the pseudo-second-order kinetic model and fitted well with the Freundlich model, suggesting that the adsorption of MO onto CuZn-HDS/Alg-0.5 was a multilayer chemical adsorption process. More importantly, CuZn-HDS/Alg-0.5 could selectively adsorb MO from MO & RhB (Rhodamine B) and MO & MB (Methylene blue) mixed solution. Mechanism studies indicated that the removal of MO was attributed to the electrostatic interaction, complexation interaction and ion exchange interaction between MO and CuZn-HDS/Alg-0.5. This work opens a new route for developing eco-friendly and efficient adsorbents to remove dyes from wastewater.

Paper-based sensors for visual detection of alkaline phosphatase and alpha-fetoprotein via the distance readout

The development of paper-based sensors with the distance readout is particularly attractive for the point-of-care testing (POCT) of biomarkers. Herein, we report a paper-based sensor that can convert the viscosity change caused by the hydrogel degradation into the variance of water flow distance on the paper. The detection of alkaline phosphatase (ALP) and alpha-fetoprotein (AFP) is demonstrated as examples. Copper alginate (Cu-Alg) hydrogel can be formed when mixing the aqueous solutions of Cu2+ and alginate. The introduction of pyrophosphate ion (PPi) induces the gel-sol transition due to the high affinity between Cu2+ and PPi. However, in the presence of ALP, the gel-sol transition is prevented due to the hydrolysis of PPi by ALP. In these processes, the viscosity changes of the hydrogels are translated into the differences of the flow distances on the pH test papers. In addition, the tilt of the papers can increase the accuracy of detection. The detection of AFP is also fulfilled via the construction of the paper-based immunosensor using the ALP-linked AFP detection antibody. The developed paper-based sensors show excellent performance for the quantitative detection of biomarkers in real samples with remarkable selectivity. Overall, this convenient method has great potential in POCT applications.

Ion-Induced Polysaccharide Gelation: Peculiarities of Alginate Egg-Box Association with Different Divalent Cations.

Structural aspects of polysaccharide hydrogels based on sodium alginate and divalent cations Ba2+, Ca2+, Sr2+, Cu2+, Zn2+, Ni2+ and Mn2+ was studied using data on hydrogel elemental composition and combinatorial analysis of the primary structure of alginate chains. It was shown that the elemental composition of hydrogels in the form of freezing dried microspheres gives information on the structure of junction zones in the polysaccharide hydrogel network, the degree of filling of egg-box cells by cations, the type and magnitude of the interaction of cations with alginate chains, the most preferred types of alginate egg-box cells for cation binding and the nature of alginate dimers binding in junction zones. It was ascertained that metal-alginate complexes have more complicated organization than was previously desired. It was revealed that in metal-alginate hydrogels, the number of cations of various metals per C12 block may be less than the limiting theoretical value equal to 1 for completely filled cells. In the case of alkaline earth metals and zinc, this number is equal to 0.3 for calcium, 0.6 for barium and zinc and 0.65-0.7 for strontium. We have determined that in the presence of transition metals copper, nickel and manganese, a structure similar to an egg-box is formed with completely filled cells. It was determined that in nickel-alginate and copper-alginate microspheres, the cross-linking of alginate chains and formation of ordered egg-box structures with completely filled cells are carried out by hydrated metal complexes with complicated composition. It was found that an additional characteristic of complex formation with manganese cations is the partial destruction of alginate chains. It has been established that the existence of unequal binding sites of metal ions with alginate chains can lead to the appearance of ordered secondary structures due to the physical sorption of metal ions and their compounds from the environment. It was shown that hydrogels based on calcium alginate are most promising for absorbent engineering in environmental and other modern technologies.

Improvement of Laccase Production by Thielavia terrestris Co3Bag1. Enhancing the Bio-Catalytic Performance of the Native Thermophilic TtLacA via Immobilization in Copper Alginate Gel Beads.

A 32-fold increase in laccase activity production by the thermophilic biomass-degrading fungus T. terrestris Co3Bag1 was achieved when the microorganism was grown on a modified medium containing fructose, sodium nitrate, and copper. A 70 kDa laccase (TtLacA), produced under the above conditions, was purified, immobilized in copper alginate gel beads, and characterized. TtLacA, both free and immobilized enzymes, exhibited optimal activity at pH 3.0, at a temperature of 65 and 70 °C, respectively, although both displayed 70% of activity from 40 to 70 °C. Free and immobilized enzymes retained at least 80% of relative activity in the pH range from 3 to 4.6. Immobilized TtLacA manifested a 2.3-fold higher thermal stability than the free form of the enzyme at 60 and 70 °C. Immobilized TtLacA retained 95% initial activity for six consecutive reuse cycles at 60 °C, and also retained 86% of initial activity after 12 days of storage at 4 °C. Based on the biochemical features, thermophilic TtLacA may be an efficient enzyme for dye decolorization and other industrial applications at high temperatures or acidic conditions. This work represents the first report about the immobilization and biochemical characterization of a thermophilic laccase from a member of the genus Thielavia.

Ultrasmall Cu3(PO4)2 Nanoparticles Reinforced Hydrogel Membrane for Super-antifouling Oil/Water Emulsion Separation.

Membrane fouling is a persistent and crippling challenge for oily wastewater treatment due to the high susceptibility of membranes to contamination. A feasible strategy is to design a robust and stable hydration layer on the membrane surface to prevent contaminates. A hydrogel illustrates a distinct category of materials with outstanding antifouling performance but is limited by its weak mechanical property. In this research, we report a reinforced hydrogel on a membrane by in situ growing ultrasmall hydrophilic Cu3(PO4)2 nanoparticles in a copper alginate (CuAlg) layer via metal-ion-coordination-mediated mineralization. The embeddedness of hydrophilic Cu3(PO4)2 nanoparticle with a size of 3-5 nm endows the CuAlg/Cu3(PO4)2 composite hydrogel with enhanced mechanical property as well as reinforced hydrate ability. The as-prepared CuAlg/Cu3(PO4)2 modified membrane exhibits a superior oil-repulsive property and achieves a nearly zero flux decline for separating surfactant stabilized oil-in-water emulsions with a high permeate flux up to ∼1330 L m-2 h-1 bar-1. Notably, it is capable of keeping similar permeate flux for both pure water and oil-in-water emulsions during filtration, which is superior to the currently reported membranes, indicating its super-antifouling properties.

Development of multifunctional copper alginate and bio-polyurethane bilayer coated fertilizer: Controlled-release, selenium supply and antifungal

Bio-based controlled release fertilizers (BCRFs) are cost-effective and renewable thus gradually replacing petroleum-based controlled release fertilizers (CRFs). However, most of the study mainly focused on modifying BCRFs to improve controlled-release performance. It is necessary to further increase the functionality of BCRF for expanding the application. A multifunctional double layered bio-based CRF (DCRF) was prepared. Urea was used as the core of fertilizer, bio-based polyurethane was used as the inner coating, and sodium alginate and copper ions formed the hydrogel as the outer coating. In addition, mesoporous silica nanoparticles loaded with sodium selenate was used to modify the sodium alginate hydrogel (MSN@Se hydrogel). The results showed that the nitrogen longevity of the DCRF was much better than that of urea and BCRF. The selenium nutrient longevity of the DCRF was 40 h, much longer than that of sodium selenate. The DCRF improved the yield and nutritive value of cherry radish (Raphanus sativus L. var.radculus pers) with the elevated contents of selenium, an essential trace element. Moreover, the DCRF showed inhibitory effect on Fusarium oxysporum Schltdl. and could resist soil-borne fungal diseases continuously. Overall, this multifunctional fertilizer has great potential for expanding the use of BCRFs for sustainable development of agriculture.

Adsorption Capacity of Tetracycline in Solution by Cu-BTC@Carboxyl-Functionalized Carbon Nanotubes@Copper Alginate Composite Aerogel Beads

In order to remove tetracycline (TC) from sewage more effectively, the adsorption performance of TC on alginate composite aerogel beads containing carbon nanomaterials was studied systematically. Carboxylated functionalized carbon nanotubes (F-CNTs)@Cu-based metal-organic framework (Cu-BTC) carbon nanomaterial composites (F-C) were prepared by a hydrothermal method, and the F-C powders were coated and fixed by macromolecular polymer copper alginate (CA). Then, F-CNTs@Cu-BTC@CA composite aerogel beads (F-C-CA) were prepared by a vacuum freeze-drying method. The new composite was characterized by BET, SEM, FTIR, and TGA, and its physical and chemical properties were analyzed. The results of batch adsorption experiments showed that F-C-CA aerogel beads had excellent adsorption capacity for TC. At 303 K, 10 mg F-C-CA aerogel beads adsorbed 20 mL 100 mg·L−1 TC solution; the removal rate reached 94% after 48 h. After kinetic analysis, the adsorption process of F-C-CA on TC was found to be more coherent with the pseudo-second-order kinetic model (chemisorption process). The isotherm fitting analysis indicated that the adsorption behavior was more suitable to the Langmuir model (monolayer adsorption), and the fitted maximum adsorption was 297 mg·g−1.

Effective Removal of Tetracycline from Water Using Copper Alginate @ Graphene Oxide with In-Situ Grown MOF-525 Composite: Synthesis, Characterization and Adsorption Mechanisms.

For nanomaterials, such as GO and MOF-525, aggregation is the main reason limiting their adsorption performance. In this research, Alg-Cu@GO@MOF-525 was successfully synthesized by in-situ growth of MOF-525 on Alg-Cu@GO. By dispersing graphene oxide (GO) with copper alginate (Alg-Cu) with three-dimensional structure, MOF-525 was in-situ grown to reduce aggregation. The measured specific surface area of Alg-Cu@GO@MOF-525 was as high as 807.30 m2·g−1, which is very favorable for adsorption. The synthesized material has affinity for a variety of pollutants, and its adsorption performance is significantly enhanced. In particular, tetracycline (TC) was selected as the target pollutant to study the adsorption behavior. The strong acid environment inhibited the adsorption, and the removal percentage reached 96.6% when pH was neutral. Temperature promoted the adsorption process, and 318 K adsorption performance was the best under experimental conditions. Meanwhile, 54.6% of TC could be removed in 38 min, and the maximum adsorption capacity reached 533 mg·g−1, far higher than that of conventional adsorption materials. Kinetics and isotherms analysis show that the adsorption process accords with Sips model and pseudo-second-order model. Thermodynamic study further shows that the chemisorption is spontaneous and exothermic. In addition, pore-filling, complexation, π-π stack, hydrogen bond and chemisorption are considered to be the causes of adsorption.

Filtration and adsorption of tetracycline in aqueous solution by copper alginate-carbon nanotubes membrane which has the muscle-skeleton structure

Recently, removal of antibiotic contaminants such as tetracycline (TC) from wastewater has been widely studied. In this study, we innovatively used copper alginate as the substrate and carbon nanotubes (CNTs) as the framework to obtain copper alginate-carbon nanotubes (CA-CNTs) composite membrane which has the “muscle-skeleton” structure after vacuum freeze-drying, cross-linking reaction and natural drying. Its performance on TC removal was verified from both filtration and adsorption. As shown by various analytical methods, the prepared composite membranes have good filtration and adsorption performance, with a maximum filtration removal rate of 95.03 % and a maximal adsorption capacity of 230.17 mg·g−1 at 318 K. The adsorption equilibrium data were well in accordance with the Langmuir isothermal model and the pseudo-second-order kinetic model. In addition, the thermodynamic analysis showed that the adsorption action of TC by CA-CNTs membranes was spontaneous and endothermic. In terms of principle and mechanism, copper alginate (CA) and CNTs were mainly bonded by hydrogen bonds, and the adsorption of TC was mainly accomplished by hydrogen bonds, cation bonding bridges and n-π EDA interactions. Meanwhile, it still had good adsorption performance after five regeneration cycles. Therefore, the prepared composite membrane has a good prospect in the application of TC removal.

Synthesis of calcium, copper and iron alginate hydrogels doped with Ag nanoparticles produced by chemical reduction method

Calcium, copper and iron alginate hydrogels were synthesized at room temperature via using the internal gelation method from sodium alginate precursor. Also, Ag nanoparticles which were produced with chemical reduction method, were added to hydrogels with different ratios (1%, 5% and 10%) to examine the different ratio effect on hydrogel properties, especially for antibacterial behaviors. According to this experimental design, the dopant ratio efficiency of Ag nanoparticles and comparison of divalent crosslinking metal ions (Ca2+, Cu2+, Fe2+) on antibacterial properties of produced hydrogels were compared. SEM-EDS analyze was done to observe Ag nanoparticles. Both SEM and UV–Vis analyzes showed that particle size of produced Ag were ∼10 nm. The chemical structures of each hydrogel were observed with FTIR studies. After structural properties of hydrogels and Ag nanoparticles examinations, antibacterial behaviors were observed with Escherichia coli and Staphylococcus aureus environments. The results showed that 10 wt% Nano-Ag doped copper alginate against Escherichia coli and 10 wt% Nano-Ag doped copper alginate against Staphylococcus aureus showed the highest antibacterial properties.

A comparative study of free laccase and laccase immobilized in copper alginate

Enzyme immobilization has gained considerable attention due to the incredible properties exhibited by the enzymes in immobilized condition. Therefore, in the present study, a comparative analysis of free and immobilized laccase is reported using various substrates. The ideal substrate for immobilization was found to be copper alginate with an immobilization yield of 91.078%. The optimum pH was 4 and 5, respectively, for free and immobilized enzymes while the optimum temperature was found to be 50 and 60C, respectively. The kinetic parameters Vmax and Km were found from the Line weaver-Burk plot and were 48.076 U/mL and 0.480 mM for free enzyme while 55.55 U/mL and 1.277 mM for the immobilized enzyme, respectively. The catalytic efficiency Kcat was found as 100.01s1 for free enzyme and 43.5s1 for its immobilized counterpart. Out of the various metal ions used, Co2+ was found to enhance the activity of an immobilized enzymes. The storage stability of the enzyme was studied and was found that only 32.44% of initial activity was retained by free enzyme whereas, 70.21% of activity was retained by immobilized enzyme upon storage for four weeks at 4C. The thermal stability studies shows that the immobilized enzyme retained 32.60% of its initial activity and the free enzyme retained 1.14% of initial activity on exposure to 60C for 3 h. Finally, the reusability of immobilized laccase beads was evaluated by decolorization of methyl orange for five repeated cycles and a percentage decolorization of 32.04% could be retained at the fifth cycle. This study therefore, suggests copper alginate-immobilized beads to be an effective option for various applications

Copper alginate surface for perpetual Self-Polishing and Anti-Biofouling compound release

Biofouling is a severe problem for many applied technical surfaces ranging from ships and piers to water inlets and medicine. Here we investigate the physical–chemical properties of divalent copper and divalent calcium alginate bulk films and their anti-biofouling properties on the example of Chlorella vulgaris and in a natural river water environment. Physical-chemical characterization includes mechanical characterization of different mixing ratios, oil contact angles, and equilibrium water contents, self-polishing properties and copper ion release of copper alginate and copper-calcium alginate compositions. The results prove highly composition dependent physical–chemical properties. This causes highly composition dependent antibiofouling properties against Chlorella vulgaris, which changes significantly over time due to copper ion release and self-polishing resulting into up to 100 times lower biofouling compared to glass slides. Extending the test to river water, less Chlorella vulgaris compared to pure Chlorella vulgaris solution were determined. The total biofouling, which reached however, saturation of 25% and 35% coverage for copper, and calcium alginate respectively, which is comparable to glass.

Strong adsorption properties and mechanism of action with regard to tetracycline adsorption of double-network polyvinyl alcohol-copper alginate gel beads

In the present study, glutaraldehyde was used as a hydrophobic modifier to crosslink polyvinyl alcohol (PVA), and copper ion was immobilized by sodium alginate (SA). Polyvinyl alcohol-copper alginate (PVA-CA) gel beads were prepared by a one-step process, and were used to adsorb and remove tetracycline (TC) from an aqueous solution. The beads were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) measurement, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). The adsorption experiment showed that the optimal pH value of the beads was 5, and that their adsorption met pseudo-second-order kinetic and Langmuir isothermal models. The adsorption thermodynamics experiment showed that the adsorption process was spontaneous and endothermic. Under optimal adsorption conditions, the maximum adsorption capacity for TC of the beads was 231.431 mg/g, which was much higher than that of a single copper alginate matrix. After 5 adsorption-desorption cycles, the adsorption capacity remained high. FTIR and X-ray photoelectron spectroscopy (XPS) revealed that the cation bonding bridge reaction was the main driving force behind the adsorption mechanism. Compared with other reported adsorption materials, the PVA-CA gel beads have high adsorption capacity, a simple preparation process, and excellent recovery performance.

Laccase Immobilization Strategies for Application as a Cathode Catalyst in Microbial Fuel Cells for Azo Dye Decolourization.

Enzymatic biocathodes have the potential to replace platinum as an expensive catalyst for the oxygen reduction reaction in microbial fuel cells (MFCs). However, enzymes are fragile and prone to loss of activity with time. This could be circumvented by using suitable immobilization techniques to maintain the activity and increase longevity of the enzyme. In the present study, laccase from Trametes versicolor was immobilized using three different approaches, i.e., crosslinking with electropolymerized polyaniline (PANI), entrapment in copper alginate beads (Cu-Alg), and encapsulation in Nafion micelles (Nafion), in the absence of redox mediators. These laccase systems were employed in cathode chambers of MFCs for decolourization of Acid orange 7 (AO7) dye. The biocatalyst in the anode chamber was Shewanella oneidensis MR-1 in each case. The enzyme in the immobilized states was compared with freely suspended enzyme with respect to dye decolourization at the cathode, enzyme activity retention, power production, and reusability. PANI laccase showed the highest stability and activity, producing a power density of 38 ± 1.7 mW m−2 compared to 25.6 ± 2.1 mW m−2 for Nafion laccase, 14.7 ± 1.04 mW m−2 for Cu-Alg laccase, and 28 ± 0.98 mW m−2 for the freely suspended enzyme. There was 81% enzyme activity retained after 1 cycle (5 days) for PANI laccase compared to 69% for Nafion and 61.5% activity for Cu-alginate laccase and 23.8% activity retention for the freely suspended laccase compared to initial activity. The dye decolourization was highest for freely suspended enzyme with over 85% decolourization whereas for PANI it was 75.6%, Nafion 73%, and 81% Cu-alginate systems, respectively. All the immobilized laccase systems were reusable for two more cycles. The current study explores the potential of laccase immobilized biocathode for dye decolourization in a microbial fuel cell.