Laccase immobilization onto natural polysaccharides for biosensing and biodegradation

Hydrogel microspheres immobilized lipase inspired by golf ball surfaces for the deacidification of Antarctic krill oil

Lipase-catalyzed esterification for enhancing oil quality has garnered extensive attention due to its eco-friendly and efficient merits. Nevertheless, during the catalytic esterification process at the oil-water interface to reduce acid value, the immobilized lipase is prone to detachment as a result of continuous mechanical agitation. In this study, inspired by the aerodynamic theory of golf ball surfaces, a novel immobilized enzyme system is designed and fabricated to improve the quality of Antarctic krill oil and prolong its storage time. The surface of the poly-pullulan hydrogel microspheres is chemically modified to expose numerous active reaction sites, forming a pitted structure similar to that of a golf ball. These pits on the surface of the microspheres can effectively mitigate the impact of the oil phase fluid on the immobilized enzyme on the surface of the carriers during the catalytic process, reducing lipase shedding and enhancing the catalytic reuse rate of the immobilized enzyme system. The obtained immobilized enzyme microspheres can still retain 70.1 % of the initial activity after 10 reuses. The high acid value of Antarctic krill oil (10.14mgKOH/g) can be effectively esterified and deacidified, and the acid value can be decreased to 2.18mgKOH/g.

3D Printing of Hydrogel Polysaccharides for Biomedical Applications: A Review

Additive manufacturing, also known as 3D printing, is becoming more and more popular because of its wide range of materials and flexibility in design. Layer by layer, 3D complex structures can be generated by the revolutionary computer-aided process known as 3D bioprinting. It is particularly crucial for youngsters and elderly patients and is a useful tool for tailored pharmaceutical therapy. A lot of research has been carried out recently on the use of polysaccharides as matrices for tissue engineering and medication delivery. Still, there is a great need to create affordable, sustainable bioink materials with high-quality mechanical, viscoelastic, and thermal properties as well as biocompatibility and biodegradability. The primary biological substances (biopolymers) chosen for the bioink formulation are proteins and polysaccharides, among the several resources utilized for the creation of such structures. These naturally occurring biomaterials give macromolecular structure and mechanical qualities (biomimicry), are generally compatible with tissues and cells (biocompatibility), and are harmonious with biological digesting processes (biodegradability). However, the primary difficulty with the cell-laden printing technique (bioprinting) is the rheological characteristics of these natural-based bioinks. Polysaccharides are widely used because they are abundant and reasonably priced natural polymers. Additionally, they serve as excipients in formulations for pharmaceuticals, nutraceuticals, and cosmetics. The remarkable benefits of biological polysaccharides-biocompatibility, biodegradability, safety, non-immunogenicity, and absence of secondary pollution-make them ideal 3D printing substrates. The purpose of this publication is to examine recent developments and challenges related to the 3D printing of stimuli-responsive polysaccharides for site-specific medication administration and tissue engineering.

Chemistry of lignin and condensed tannins as aromatic biopolymers

Aromatic biopolymers are the second largest group of biopolymers after polysaccharides. Depolymerization of aromatic biopolymers, as cheap and renewable substitutes for fossil-based resources, has been used in the preparation of biofuels, and a range of aromatic and aliphatic small molecules. Additionally, these polymers exhibit a robust UV-shielding function due to the high content of aromatic groups. Meanwhile, the abundance of phenolic groups in their structures gives these compounds outstanding antioxidant capabilities, making them well-suited for a diverse array of anti-UV and medical applications. Nevertheless, these biopolymers possess inherent drawbacks in their pristine states, such as rigid structure, low solubility, and lack of desired functionalities, which hinder their complete exploitation across diverse sectors. Thus, the modification and functionalization of aromatic biopolymers are essential to provide them with specific functionalities and features needed for particular applications. Aromatic biopolymers include lignins, tannins, melanins, and humic acids. The objective of this review is to offer a thorough reference for assessing the chemistry and functionalization of lignins and condensed tannins. Lignins represent the largest and most prominent category of aromatic biopolymers, typically distinguishable as either softwood-derived or hardwood-derived lignins. Besides, condensed tannins are the most investigated group of the tannin family. The electron-rich aromatic rings, aliphatic hydroxyl groups, and phenolic groups are the main functional groups in the structure of lignins and condensed tannins. Methoxy groups are also abundant in lignins. Each group displays varying chemical reactivity within these biopolymers. Therefore, the selective and specific functionalization of lignins and condensed tannins can be achieved by understanding the chemistry behavior of these functional groups. Targeted applications include biomedicine, monomers and surface active agents for sustainable plastics.

From nature to applications: Laccase immobilization onto bio-based materials for eco-conscious environmental remediation

Biodegradable and sustainable materials utilized for laccase immobilization have garnered substantial scholarly interest owing to their capacity to enhance enzyme stability and reusability, which are paramount for effective bioremediation methodologies. Laccase, a versatile oxidase, possesses the ability to degrade a broad spectrum of environmental contaminants, thus rendering it an invaluable asset in bioremediation endeavours. The immobilization of laccase onto biodegradable substrates not only augments its operational stability but also resonates with sustainable environmental strategies. This article systematically investigates recent advancements in sustainable and eco-conscious methodologies aimed at immobilizing laccase. By integrating biodegradable and non-toxic components, we elucidated how these materials not only proficiently enhanced the operational stability of laccases, but also improved their biodegradation effectiveness. A comprehensive analysis revealed that these sustainable materials facilitate immobilized laccase-mediated efficient removal of hazardous chemicals. Furthermore, we highlight the challenges that persist despite the encouraging characteristics of sustainable and eco-friendly approaches to laccase immobilization and pollutant elimination, and engage in discourse regarding potential pathways for their broader application and scalable solutions. This review highlights the significance of incorporating green technologies into environmental remediation efforts, thereby fostering the development of more effective and ecologically sound solutions for sustainable laccase immobilization to mitigate environmental contaminants efficiently.

Exploring Botryosphaeran, a (1 → 3)(1 → 6)-β-D-Glucan, as a Matrix for the Stabilization of Laccase from Pleurotus ostreatus Florida onto a Zinc Oxide Quantum Dots Platform for the Electrochemical Determination of 2,6-Dimethoxyphenol

This work describes the development of a novel biosensor obtained by immobilizing laccase from Pleurotus ostreatus Florida onto a glassy carbon electrode platform modified with zinc oxide quantum dots. For enzyme immobilization, the exopolysaccharide botryosphaeran from Botryosphaeria rhodina MAMB-05 was used. Although both biomaterials are from different fungal sources, laccase immobilization was guaranteed, which was demonstrated by the excellent stability of the fabricated biosensor device for the voltammetric determination of 2,6-dimethoxyphenol (2,6-DMP). Under the optimal experimental conditions, the cathodic current from the square-wave voltammograms presented a linear dependence on the 2,6-DMP concentration within the range of 10-400 nmol L-1, with a limit of detection of 9 nmol L-1. This bioanalytical device exhibited excellent repeatability and long-term storage stability.

Synergistic microglial modulation by laminarin-based platinum nanozymes for potential intracerebral hemorrhage therapy

Abnormal microglial activation increases inflammation, causing significant brain damage after intracerebral hemorrhage (ICH). To aid recovery, treatments should regulate oxidative stress and inhibit the M1-like phenotype (pro-inflammation) of microglia. Recently, antioxidant nanozymes have emerged as tools for modulating microglial states, but detailed studies on their role in ICH treatment are limited. To address this, we developed an ultra-small (3-4 nm) laminarin-modified platinum nanozyme (Pt@LA) for the synergistic regulation of microglial polarization, offering a novel therapeutic strategy for ICH. Pt@LA effectively scavenges reactive oxygen species (ROS) through superoxide dismutase (SOD) and catalase (CAT)-like activities. Laminarin may inhibit the Dectin-1 receptor on microglia and its inflammatory pathway, Syk/NF-κB, reducing neuroinflammation. In vitro, Pt@LA decreased pro-inflammatory microglia and cytokine expression by inhibiting the Dectin-1/Syk/NF-κB and ROS-mediated NF-κB pathways. Furthermore, Pt@LA protected neurons, inhibited glial scar formation, and improved neurological function in ICH rats. Overall, this study presents Pt nanozymes based on naturally extracted laminarin and explores their application in alleviating oxidative stress and neuroinflammation after ICH, bridging nanozyme research and neuroscience.

Nanocarriers for Delivery of Anticancer Drugs: Current Developments, Challenges, and Perspectives

Cancer, the most common condition worldwide, ranks second in terms of the number of human deaths, surpassing cardiovascular diseases. Uncontrolled cell multiplication and resistance to cell death are the traditional features of cancer. The myriad of treatment options include surgery, chemotherapy, radiotherapy, and immunotherapy to treat this disease. Conventional chemotherapy drug delivery suffers from issues such as the risk of damage to benign cells, which can cause toxicity, and a few tumor cells withstand apoptosis, thereby increasing the likelihood of developing tolerance. The side effects of cancer chemotherapy are often more pronounced than its benefits. Regarding drugs used in cancer chemotherapy, their bioavailability and stability in the tumor microenvironment are the most important issues that need immediate addressing. Hence, an effective and reliable drug delivery system through which both rapid and precise targeting of treatment can be achieved is urgently needed. In this work, we discuss the development of various nanobased carriers in the advancement of cancer therapy-their properties, the potential of polymers for drug delivery, and recent advances in formulations. Additionally, we discuss the use of tumor metabolism-rewriting nanomedicines in strengthening antitumor immune responses and mRNA-based nanotherapeutics in inhibiting tumor progression. We also examine several issues, such as nanotoxicological studies, including their distribution, pharmacokinetics, and toxicology. Although significant attention is being given to nanotechnology, equal attention is needed in laboratories that produce nanomedicines so that they can record themselves in clinical trials. Furthermore, these medicines in clinical trials display overwhelming results with reduced side effects, as well as their ability to modify the dose of the drug.

Polysaccharide nanosystems for osteoarthritis therapy: Mechanisms, combinations, and future directions

Osteoarthritis (OA) represents a chronic degenerative joint ailment characterized by the gradual breakdown of cartilage, inflicting substantial physical and economic burdens, especially among the elderly. Given the incomplete understanding of OA's pathogenesis, there is an increasing need to develop targeted therapeutic strategies and preventive measures. Conventional pharmaceutical interventions, such as non-steroidal anti-inflammatory drugs, steroids, and opioids, though effective, are often accompanied by notable adverse effects, thus emphasizing the urgency in seeking safer and more efficient therapeutic alternatives. The rapid evolution of nanotechnology has opened the door to various nanosystems for drug delivery, offering a promising avenue to mitigate these side effects. Of particular interest, recent research has shed light on the significant potential of polysaccharide-based nanosystems in the context of OA therapy, demonstrating their capability to counter inflammation, oxidative stress, regulate chondrocyte metabolism and proliferation, and protect cartilage. Therefore, in this review, we provide an in-depth examination of the role of polysaccharide nanosystems in OA, focusing on summarizing these findings based on different mechanisms of action. Furthermore, this review explores the application of combined polysaccharide nanosystems in OA, aiming to establish a foundation for the utilization of novel drug delivery nanoplatforms in OA treatment, ultimately expanding therapeutic options for this debilitating condition.

A green approach to encapsulate proteins and enzymes within crystalline lanthanide-based Tb and Gd MOFs

In this work, bovine serum albumin (BSA) and Aspergillus sp. laccase (LC) were encapsulated in situ within two lanthanide-based MOFs (TbBTC and GdBTC) through a green one-pot synthesis (almost neutral aqueous solution, T = 25 °C, and atmospheric pressure) in about 1 h. Pristine MOFs and protein-encapsulated MOFs were characterized through wide angle X-ray scattering, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared and Raman spectroscopies. The location of immobilized BSA molecules, used as a model protein, was investigated through small angle X-ray scattering. BSA occurs both on the inner and on the outer surface of the MOFs. LC@TbBTC, and LC@GdBTC samples were also characterized in terms of specific activity, kinetic parameters, and storage stability both in water and acetate buffer. The specific activity of LC@TbBTC was almost twice that of LC@GdBTC (10.8 μmol min-1 mg-1vs. 6.6 μmol min-1 mg-1). Both biocatalysts showed similar storage stabilities retaining ∼60% of their initial activity after 7 days and ∼20% after 21 days. LC@TbBTC dispersed in acetate buffer exhibited a higher storage stability than LC@GdBTC. Additionally, terbium-based MOFs showed interesting luminescent properties. Together, these findings suggest that TbBTC and GdBTC are promising supports for the in situ immobilization of proteins and enzymes.

Eco-Friendly g-C3N4/Carboxymethyl Cellulose/Alginate Composite Hydrogels for Simultaneous Photocatalytic Degradation of Organic Dye Pollutants

The presented study was focused on the simple, eco-friendly synthesis of composite hydrogels of crosslinked carboxymethyl cellulose (CMC)/alginate (SA) with encapsulated g-C3N4 nanoparticles. The structural, textural, morphological, optical, and mechanical properties were determined using different methods. The encapsulation of g-C3N4 into CMC/SA copolymer resulted in the formation of composite hydrogels with a coherent structure, enhanced porosity, excellent photostability, and good adhesion. The ability of composite hydrogels to eliminate structurally different dyes with the same or opposite charge properties (cationic Methylene Blue and anionic Orange G and Remazol Brilliant Blue R) in both single- and binary-dye systems was examined through adsorption and photocatalytic reactions. The interactions between the dyes and g-C3N4 and the negatively charged CMC/SA copolymers had a notable influence on both the adsorption capacity and photodegradation efficiency of the prepared composites. Scavenger studies and leaching tests were conducted to gain insights into the primary reactive species and to assess the stability and long-term performance of the g-C3N4/CMC/SA beads. The commendable photocatalytic activity and excellent recyclability, coupled with the elimination of costly catalyst separation requirements, render the g-C3N4/CMC/SA composite hydrogels cost-effective and environmentally friendly materials, and strongly support their selection for tackling environmental pollution issues.

Thermostabilization of a fungal laccase by entrapment in enzymatically synthesized levan nanoparticles

In this work, we present a comprehensive investigation of the entrapment of laccase, a biotechnologically relevant enzyme, into levan-based nanoparticles (LNPs). The entrapment of laccase was achieved concomitantly with the synthesis of LNP, catalyzed by a truncated version of a levansucrase from Leuconostoc mesenteroides. The study aimed to obtain a biocompatible nanomaterial, able to entrap functional laccase, and characterize its physicochemical, kinetic and thermal stability properties. The experimental findings demonstrated that a colloidal stable solution of spherically shaped LNP, with an average diameter of 68 nm, was obtained. An uniform particle size distribution was observed, according to the polydispersity index determined by DLS. When the LNPs synthesis was performed in the presence of laccase, biocatalytically active nanoparticles with a 1.25-fold larger diameter (85 nm) were obtained, and a maximum load of 243 μg laccase per g of nanoparticle was achieved. The catalytic efficiency was 972 and 103 (μM·min)-1, respectively, for free and entrapped laccase. A decrease in kcat values (from 7050 min-1 to 1823 min-1) and an increase in apparent Km (from 7.25 μM to 17.73 μM) was observed for entrapped laccase, compared to the free enzyme. The entrapped laccase exhibited improved thermal stability, retaining 40% activity after 1 h-incubation at 70°C, compared to complete inactivation of free laccase under the same conditions, thereby highlighting the potential of LNPs in preserving enzyme activity under elevated temperatures. The outcomes of this investigation significantly contribute to the field of nanobiotechnology by expanding the applications of laccase and presenting an innovative strategy for enhancing enzyme stability through the utilization of fructan-based nanoparticle entrapments.

Tailor-Made Polysaccharides for Biomedical Applications

Polysaccharides (PSAs) are carbohydrate-based macromolecules widely used in the biomedical field, either in their pure form or in blends/nanocomposites with other materials. The relationship between structure, properties, and functions has inspired scientists to design multifunctional PSAs for various biomedical applications by incorporating unique molecular structures and targeted bulk properties. Multiple strategies, such as conjugation, grafting, cross-linking, and functionalization, have been explored to control their mechanical properties, electrical conductivity, hydrophilicity, degradability, rheological features, and stimuli-responsiveness. For instance, custom-made PSAs are known for their worldwide biomedical applications in tissue engineering, drug/gene delivery, and regenerative medicine. Furthermore, the remarkable advancements in supramolecular engineering and chemistry have paved the way for mission-oriented biomaterial synthesis and the fabrication of customized biomaterials. These materials can synergistically combine the benefits of biology and chemistry to tackle important biomedical questions. Herein, we categorize and summarize PSAs based on their synthesis methods, and explore the main strategies used to customize their chemical structures. We then highlight various properties of PSAs using practical examples. Lastly, we thoroughly describe the biomedical applications of tailor-made PSAs, along with their current existing challenges and potential future directions.

Laccase immobilization and its degradation of emerging pollutants: A comprehensive review

The chronic lack of effective disposal of pollutants has resulted in the detection of a wide variety of EPs in the environment, with concentrations high enough to affect ecological health. Laccase, as a versatile oxidase capable of catalyzing a wide range of substrates and without producing toxic by-products, is a potential candidate for the biodegradation of pollutants. Immobilization can provide favorable protection for free laccase, improve the stability of laccase in complex environments, and greatly enhance the reusability of laccase, which is significant in reducing the cost of industrial applications. This study introduces the properties of laccase and subsequently elaborate on the different support materials for laccase immobilization. The research advances in the degradation of EDs, PPCPs, and PAHs by immobilized laccase are then reviewed. This review provides a comprehensive understanding of laccase immobilization, as well as the advantages of various support materials, facilitating the development of more economical and efficient immobilization systems that can be put into practice to achieve the green degradation of EPs.

Recent Progress and Future Prospects of Laccase Immobilization on MOF Supports for Industrial Applications

Laccase is a multicopper oxidoreductase enzyme that can oxidize organics such as phenolic compounds. Laccases appear to be unstable at room temperature, and their conformation often changes in a strongly acidic or alkaline environment, making them less effective. Therefore, rationally linking enzymes with supports can effectively improve the stability and reusability of native enzymes and add important industrial value. However, in the process of immobilization, many factors may lead to a decrease in enzymatic activity. Therefore, the selection of a suitable support can ensure the activity and economic utilization of immobilized catalysts. Metal-organic frameworks (MOFs) are porous and simple hybrid support materials. Moreover, the characteristics of the metal ion ligand of MOFs can enable a potential synergistic effect with the metal ions of the active center of metalloenzymes, enhancing the catalytic activity of such enzymes. Therefore, in addition to summarizing the biological characteristics and enzymatic properties of laccase, this article reviews laccase immobilization using MOF supports, as well as the application prospects of immobilized laccase in many fields.

Highly sensitive amperometric sensors based on laccase-mimetic nanozymes for the detection of dopamine

The current research presents novel sensors based on laccase-like mimetics for the detection of dopamine (DA). The synthesized laccase-like nanozymes (nAuCu, nPtCu, nCuMnCo, and nCoCuCe) were prepared by a simple hydrothermal method and exhibited an attractive catalytic activity toward DA. The developed amperometric sensors based on laccase nanozymes (nAuCu and nPtCu) are more stable, selective, and revealed a higher sensitivity (6.5-fold than the biosensor based on the natural fungal laccase from Trametes zonata). The amperometric sensors were obtained by modification of the glassy carbon electrodes (GCEs) with AuPt nanoparticles. Functionalization of the electrode surface by AuPt NPs resulted in increased catalytic activity of the laccase-like layer and higher sensitivity. Among studied configurations, the sensor containing nAuCu and nAuPt possesses a wide linear range for dopamine detection (10-170 μM), the lowest limit of detection (20 nM), and the highest sensitivity (10 650 ± 8.3 A M-1 m-2) at a low applied potential (+0.2 V versus Ag/AgCl). The proposed simple and cost-effective sensor electrode was used for the determination of DA in pharmaceuticals.

A graphitized carbon@boron carbide-mediated laccase-based amperometric biosensor for epinephrine detection

The development of novel electron transfer mediator is important for laccase-based electrochemical biosensors. Here, graphitized carbon coated boron carbide (GC@B4C) was first used as the mediator to transfer electrons from laccase (Lac) to nickel foam (NF) electrode. The GC shell of GC@B4C particles was characterized and confirmed by HRTEM, XRD and Raman spectroscopy. The fabricated Lac/GC@B4C/NF electrode was applied for amperometric detection of epinephrine (EP). Detection results indicated Lac/GC@B4C/NF electrode has wide linear range (0.1 µM-2.6 mM), low detection limit (40 nM), high sensitivity (76.05 µA mM-1), strong anti-interference ability and favorable stability for EP detection. This work opened up the use of nonmetallic carbide as the mediator for enzyme-based electrochemical biosensors.

Enzymes Immobilized into Starch- and Gelatin-Based Hydrogels: Properties and Application in Inhibition Assay

The present work is a review of the research on using hydrogels based on natural biodegradable polymers, starch, and gelatin for enzyme immobilization. This review addresses the main properties of starch and gelatin that make them promising materials in biotechnology for producing enzyme preparations stable during use and storage and insensitive to chemical and physical impacts. The authors summarize their achievements in developing the preparations of enzymes immobilized in starch and gelatin gels and assess their activity, stability, and sensitivity for use as biorecognition elements of enzyme inhibition-based biosensors.

Application of Immobilized Enzymes in Juice Clarification

Immobilized enzymes are currently being rapidly developed and are widely used in juice clarification. Immobilized enzymes have many advantages, and they show great advantages in juice clarification. The commonly used methods for immobilizing enzymes include adsorption, entrapment, covalent bonding, and cross-linking. Different immobilization methods are adopted for different enzymes to accommodate their different characteristics. This article systematically reviews the methods of enzyme immobilization and the use of immobilized supports in juice clarification. In addition, the mechanisms and effects of clarification with immobilized pectinase, immobilized laccase, and immobilized xylanase in fruit juice are elaborated upon. Furthermore, suggestions and prospects are provided for future studies in this area.

Bionanocomposite based on immobilization of Burkholderia cepacian on GO/MOF and its removal of malachite green from river water

Bio-nanocomposites have attracted increasing research attention because they are able to integrate bio- and nano-related functions, and subsequently demonstrate potentially beneficial environmental applications. Here, a functional bionanomaterial based on Burkholderia cepacian (FZ) immobilized on GO/ZIF-8 was developed and used to remove malachite green (MG), with functions based on both biodegradation and adsorption. XRD and FTIR results showed that in situ production of GO/ZIF-8 by combining Zn2+ in ZIF-8 with the carboxyl group on the GO surface, led to FZ immobilized in GO/ZIF-8 through covalent bonding. Zeta analysis showed that the surface of FZ and GO/ZIF-8 had different charges under pH = 9.12, suggesting immobilization also occurred via electrostatic action. BET results confirmed that the specific surface area of GO/ZIF-8 was much larger than that of GO and ZIF-8, but the reduced specific surface area of FZ@GO/ZIF-8 could be due to FZ loading on its surface. The efficiency of FZ@GO/ZIF-8 in the removal of MG reached 99% and furthermore retained good stability after five cycles. The efficiency in removing multiple ions in river water reached more than 80%, which is evidence strongly suggesting that FZ@GO/ZIF-8 is an environmental bionanomaterial with effective application potential.

Laccase immobilized on nanocomposites for wastewater pollutants degradation: current status and future prospects

The bio-enzyme degradation technology is a promising approach to sustainably remove pollution in the water and laccase is one of the most widely used enzymes in this area. Nevertheless, the further industrial application of laccase is limited by low stability, short service, low reusability and high price. The immobilization technology can significantly improve the stability and reusability of enzymes and thus promoting their industrial applications. Nanocomposite materials have been developed and applied in the efficient immobilization of laccase due to their superior physical, chemical, and biological performance. This paper presents a comprehensive review of various nanocomposite immobilization methods for laccase and the consequent changes in enzymatic properties post-immobilization. Additionally, a comprehensive analysis is conducted on the factors that impact laccase immobilization and its water removal efficiency. Furthermore, this review examines the effectiveness of common contaminants' removal mechanisms while summarizing and discussing issues related to laccase immobilization on nanocomposite carriers. This review aims to provide valuable guidance for enhancing laccase immobilization efficiency and enzymatic water pollutant removal.

A critical review of enzymes immobilized on chitosan composites: characterization and applications

Enzymes with industrial significance are typically used in biological processes. However, instability, high sensitivity, and impractical recovery are the major drawbacks of enzymes in practical applications. In recent years, the immobilization technology has attracted wide attention to overcoming these restrictions and improving the efficiency of enzyme applications. Chitosan (CS) is a unique functional substance with biocompatibility, biodegradability, non-toxicity, and antibacterial properties. Chitosan composites are anticipated to be widely used in the near future for a variety of purposes, including as supports for enzyme immobilization, because of their advantages. Therefor this review explores the effects of the chitosan's structure, molecular weight, degree of deacetylation on the enzyme immobilized, effect of key factors, and the enzymes immobilized on chitosan based composites for numerous applications, including the fields of biosensor, biomedical science, food industry, environmental protection, and industrial production. Moreover, this study carefully investigates the advantages and disadvantages of using these composites as well as their potential in the future.

Chitosan-induced biotic stress tolerance and crosstalk with phytohormones, antioxidants, and other signalling molecules

Several polysaccharides augment plant growth and productivity and galvanise defence against pathogens. Such elicitors have ecological superiority over traditional growth regulators, considering their amplified biocompatibility, biodegradability, bioactivity, non-toxicity, ubiquity, and inexpensiveness. Chitosan is a chitin-derived polysaccharide that has recently been spotlighted among plant scientists. Chitosan supports plant growth and development and protects against microbial entities such as fungi, bacteria, viruses, nematodes, and insects. In this review, we discuss the current knowledge of chitosan's antimicrobial and insecticidal potential with recent updates. These effects are further explored with the possibilities of chitosan's active correspondence with phytohormones such as jasmonic acid (JA), salicylic acid (SA), indole acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GA). The stress-induced redox shift in cellular organelles could be substantiated by the intricate participation of chitosan with reactive oxygen species (ROS) and antioxidant metabolism, including hydrogen peroxide (H2O2), superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Furthermore, we propose how chitosan could be intertwined with cellular signalling through Ca2+, ROS, nitric oxide (NO), transcription factors (TFs), and defensive gene activation.

Polysaccharide-based biomaterials in a journey from 3D to 4D printing

3D printing is a state-of-the-art technology for the fabrication of biomaterials with myriad applications in translational medicine. After stimuli-responsive properties were introduced to 3D printing (known as 4D printing), intelligent biomaterials with shape configuration time-dependent character have been developed. Polysaccharides are biodegradable polymers sensitive to several physical, chemical, and biological stimuli, suited for 3D and 4D printing. On the other hand, engineering of mechanical strength and printability of polysaccharide-based scaffolds along with their aneural, avascular, and poor metabolic characteristics need to be optimized varying printing parameters. Multiple disciplines such as biomedicine, chemistry, materials, and computer sciences should be integrated to achieve multipurpose printable biomaterials. In this work, 3D and 4D printing technologies are briefly compared, summarizing the literature on biomaterials engineering though printing techniques, and highlighting different challenges associated with 3D/4D printing, as well as the role of polysaccharides in the technological shift from 3D to 4D printing for translational medicine.

Effective biodegradation of chlorophenols, sulfonamides, and their mixtures by bacterial laccase immobilized on chitin

Coexisting multi-pollutants like sulfonamides (SAs) and chlorophenols (CPs) in the ecological environment pose a potential risk to living organisms. The development of a strategy for the effective removal of multiple pollutants has become an urgent need. Herein, we systematically investigated the potential of immobilized bacterial laccase to remove chlorophenols (CPs), sulfonamides (SAs), and their mixtures. Laccase from Bacillus pumilus ZB1 was efficiently immobilized on chitin and its thermal stability, pH stability, and affinity to substrates were improved. Reusability assessment showed the immobilized laccase retained 75.5% of its initial activity after five cycles. The removal efficiency of CPs and SAs by immobilized laccase was significantly improved compared with that of free laccase. In particular, the removal of 2,4-dichlorophenol and 2,4,6-trichlorophenol reached 96.9% and 89.3% respectively within 8 h. The immobilized laccase could remove 63.70% of 2,4-dichlorophenol after four cycles. The degradation pathways of 2,4-dichlorophenol and sulfamethazine were proposed via LC/MS analysis. When the co-pollutants containing 2,4,6-trichlorophenol and sulfamethoxazole, immobilized laccase showed 100% removal of 2,4,6-trichlorophenol and 38.71% removal of sulfamethoxazole simultaneously. Cytotoxicity and phytotoxicity tests indicated that immobilized laccase can alleviate the toxicity of co-pollutants. The results demonstrate that chitin-based laccase immobilization can be an effective strategy for the removal of SAs, CPs, and their co-pollutants.

Applications and immobilization strategies of the copper-centred laccase enzyme; a review

Laccase is a multi-copper enzyme widely expressed in fungi, higher plants, and bacteria which facilitates the direct reduction of molecular oxygen to water (without hydrogen peroxide production) accompanied by the oxidation of an electron donor. Laccase has attracted attention in biotechnological applications due to its non-specificity and use of molecular oxygen as secondary substrate. This review discusses different applications of laccase in various sectors of food, paper and pulp, waste water treatment, pharmaceuticals, sensors, and fuel cells. Despite the many advantages of laccase, challenges such as high cost due to its non-reusability, instability in harsh environmental conditions, and proteolysis are often encountered in its application. One of the approaches used to minimize these challenges is immobilization. The various methods used to immobilize laccase and the different supports used are further extensively discussed in this review.

Recent advances in the utilization of immobilized laccase for the degradation of phenolic compounds in aqueous solutions: A review

Phenolic compounds such as phenol, bisphenol A, 2,4-dichlorophenol, 2,4-dinitrophenol, 4-chlorophenol and 4-nitrophenol are well known to be highly detrimental to both human and living beings. Thus, it is of critical importance that suitable remediation technologies are developed to effectively remove phenolic compounds from aqueous solutions. Biodegradation utilizing enzymatic technologies is a promising biotechnological solution to sustainably address the pollution in the aquatic environment as caused by phenolic compounds under a defined environmentally optimized strategy and thus should be investigated in great detail. This review aims to present the latest developments in the employment of immobilized laccase for the degradation of phenolic compounds in water. The review first succinctly delineates the fundamentals of biological enzyme degradation along with a critical discussion on the myriad types of laccase immobilization techniques, which include physical adsorption, ionic adsorption, covalent binding, entrapment, and self-immobilization. Then, this review presents the major properties of immobilized laccase, namely pH stability, thermal stability, reusability, and storage stability, as well as the degradation efficiencies and associated kinetic parameters. In addition, the optimization of the immobilized enzyme, specifically on laccase immobilization methods and multi-enzyme system are critically discussed. Finally, pertinent future perspectives are elucidated in order to significantly advance the developments of this research field to a higher level.

Polysaccharide-based nanocomposites for biomedical applications: a critical review

Polysaccharides (PSA) have taken specific position among biomaterials for advanced applications in medicine. Nevertheless, poor mechanical properties are known as the main drawback of PSA, which highlights the need for PSA modification. Nanocomposites PSA (NPSA) are a class of biomaterials widely used as biomedical platforms, but despite their importance and worldwide use, they have not been reviewed. Herein, we critically reviewed the application of NPSA by categorizing them into generic and advanced application realms. First, the application of NPSA as drug and gene delivery systems, along with their role in the field as an antibacterial platform and hemostasis agent is discussed. Then, applications of NPSA for skin, bone, nerve, and cartilage tissue engineering are highlighted, followed by cell encapsulation and more critically cancer diagnosis and treatment potentials. In particular, three features of investigations are devoted to cancer therapy, i.e., radiotherapy, immunotherapy, and photothermal therapy, are comprehensively reviewed and discussed. Since this field is at an early stage of maturity, some other aspects such as bioimaging and biosensing are reviewed in order to give an idea of potential applications of NPSA for future developments, providing support for clinical applications. It is well-documented that using nanoparticles/nanomaterials above a critical concentration brings about concerns of toxicity; thus, their effect on cellular interactions would become critical. We compared nanoparticles used in the fabrication of NPSA in terms of toxicity mechanism to shed more light on future challenging aspects of NPSA development. Indeed, the neutralization mechanisms underlying the cytotoxicity of nanomaterials, which are expected to be induced by PSA introduction, should be taken into account for future investigations.

Corn Cob as a Green Support for Laccase Immobilization-Application on Decolorization of Remazol Brilliant Blue R

The high demand for food and energy imposed by the increased life expectancy of the population has driven agricultural activity, which is reflected in the larger quantities of agro-industrial waste generated, and requires new forms of use. Brazil has the greatest biodiversity in the world, where corn is one of the main agricultural genres, and where over 40% of the waste generated is from cobs without an efficient destination. With the aim of the valorization of these residues, we proposed to study the immobilization of laccase from Aspergillus spp. (L_Asp) in residual corn cob and its application in the degradation of Remazol Brilliant Blue R (RBBR) dye. The highest yields in immobilized protein (75%) and residual activity (40%) were obtained at pH 7.0 and an enzyme concentration of 0.1 g.mL⁻¹, whose expressed enzyme activity was 1854 U.kg⁻¹. At a temperature of 60 °C, more than 90% of the initial activity present in the immobilized biocatalyst was maintained. The immobilized enzyme showed higher efficiency in the degradation (64%) of RBBR dye in 48 h, with improvement in the process in 72 h (75%). The new biocatalyst showed operational efficiency during three cycles, and a higher degradation rate than the free enzyme, making it a competitive biocatalyst and amenable to industrial applications.

Research Progress on Lignocellulosic Biomass Degradation Catalyzed by Enzymatic Nanomaterials

Lignocellulose biomass (LCB) has extensive applications in many fields such as bioenergy, food, medicines, and raw materials for producing value-added products. One of the keys to efficient utilization of LCB is to obtain directly available oligo- and monomers (e.g., glucose). With the characteristics of easy recovery and separation, high efficiency, economy, and environmental protection, immobilized enzymes have been developed as heterogeneous catalysts to degrade LCB effectively. In this review, applications and mechanisms of LCB-degrading enzymes are discussed, and the nanomaterials and methods used to immobilize enzymes are also discussed. Finally, the research progress of lignocellulose biodegradation catalyzed by nano-enzymes was discussed.

Laccase-loaded magnetic dialdehyde inulin nanoparticles as an efficient heterogeneous natural polymer-based biocatalyst for removal and detoxification of ofloxacin

An efficient heterogeneous natural polymer-based biocatalyst was fabricated through the immobilization of laccase onto dialdehyde inulin (DAI)-coated silica-caped magnetic nanoparticles (laccase@DAI@SiO₂@Fe₃O₄⋅MNPs). The carrier was developed using SiO₂@Fe₃O₄⋅MNPs and functionalized with DAI. The construction of immobilized laccase was confirmed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Immobilization yield and efficiency were calculated as 61.0 ± 0.3% and 93.0 ± 0.6%, respectively. The immobilized laccase maintained 50% and 85% of its relative activity after 25 repeated cycles and 20 days of storage at 4 °C, respectively. The prepared biocatalyst effectively eliminated ofloxacin, a fluoroquinolone-type antibiotic, with a 63% removal capacity. Besides, antimicrobial activity study on some soil microorganisms involved in the biodegradation of xenobiotics revealed that the laccase-treated ofloxacin resulted in less toxic metabolites. The obtained data indicated that the fabricated biocatalyst is promising for the removal of ofloxacin or other analogs of fluoroquinolones in the environment.

Biomass-derived nanocellulose aerogel enable highly efficient immobilization of laccase for the degradation of organic pollutants

Laccase is a promising biocatalyst for pollutant degradation and water purification. However, laccase can only improve the stability of enzyme activity and achieve its significant catalytic effect after effective immobilization. Herein, we report a general strategy to integrate nanocellulose aerogel and laccase for high-efficiency degradation of organic pollutants. Biomass-derived functional bacterial cellulose (BC) aerogel with a nanonetwork structure and high porosity was prepared by biosynthesis, solvent replacement, and atom transfer radical polymerization (ATRP) procedures. Subsequently, a biocatalyst platform was fabricated by "coupling" ATRP-modified BC aerogel with abundant active sites with laccase through ion coordination. The results demonstrated the biocatalyst platform not only has good biological affinity, but also has high enzyme load and structural stability. Meanwhile, the degradation rates of reactive red X-3B and 2, 4-dichlorophenol reached 94.5% and 85.2% within 4 h, respectively. The strategy disclosed herein could provide a practical method for the degradation of organic pollutants.

Laccase production from Bacillus aestuarii KSK using Borassus flabellifer empty fruit bunch waste as a substrate and assessing their malachite green dye degradation

AIMS

The lignocellulosic waste, Borassus flabellifer empty fruit bunch waste (BFEFBW), was employed to produce laccase using Bacillus aestuarii KSK under solid-state fermentation (SSF) conditions and to assess the efficiency of malachite green (MG) dye decolourization.

METHODS AND RESULTS

Abiotic factors such as pH (5.0-9.0), temperature (25-45°C) and incubation time (24-96 h) were optimized using Response surface methodology-Box-Behenan Design (RSM-BBD) to exploit the laccase production. The anticipated model revealed that the highest laccase activity of 437 U/ml shows after 60 h of incubation at 35°C at pH 7.0. The bacterial laccase was used to remove 89% of the MG dye in less time.

CONCLUSION

The laccase from B. aestuarii KSK decolorizes the MG and thereby making it a suitable choice for wastewater treatment from industrial effluents.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study is the first report on the production of laccase from B. flabellifer empty fruit bunch waste as a substrate. Bacillus aestuarii KSK was isolated from the soil sample and used to produce laccase under SSF conditions. The bacterial laccase has the potential for industrial application in textile waste dye treatment.

Nanocarriers for anticancer drugs: Challenges and perspectives

Cancer is the second most common cause of death globally, surpassed only by cardiovascular disease. One of the hallmarks of cancer is uncontrolled cell division and resistance to cell death. Multiple approaches have been developed to tackle this disease, including surgery, radiotherapy and chemotherapy. Although chemotherapy is used primarily to control cell division and induce cell death, some cancer cells are able to resist apoptosis and develop tolerance to these drugs. The side effects of chemotherapy are often overwhelming, and patients can experience more adverse effects than benefits. Furthermore, the bioavailability and stability of drugs used for chemotherapy are crucial issues that must be addressed, and there is therefore a high demand for a reliable delivery system that ensures fast and accurate targeting of treatment. In this review, we discuss the different types of nanocarriers, their properties and recent advances in formulations, with respect to relevant advantages and disadvantages of each.

Evaluation of MxOy/fucoidan hybrid system and their application in lipase immobilization process

In this work, new M_xO_y/fucoidan hybrid systems were fabricated and applied in lipase immobilization. Magnesium (MgO) and zirconium (ZrO₂) oxides were used as M_xO_y inorganic matrices. In the first step, the proposed oxides were functionalized with fucoidan from Fucus vesiculosus (Fuc). The obtained MgO/Fuc and ZrO₂/Fuc hybrids were characterized by means of spectroscopic analyses, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance. Additionally, thermogravimetric analysis was performed to determine the thermal stability of the hybrids. Based on the results, the mechanism of interaction between the oxide supports and fucoidan was also determined. Furthermore, the fabricated M_xO_y/fucoidan hybrid materials were used as supports for the immobilization of lipase from Aspergillus niger, and a model reaction (transformation of p-nitrophenyl palmitate to p-nitrophenol) was performed to determine the catalytic activity of the proposed biocatalytic system. In that reaction, the immobilized lipase exhibited high apparent and specific activity (145.5 U/g_catalyst and 1.58 U/mg_enzyme for lipase immobilized on MgO/Fuc; 144.0 U/g_catalyst and 2.03 U/mg_enzyme for lipase immobilized on ZrO₂/Fuc). The immobilization efficiency was also confirmed using spectroscopic analyses (FTIR and XPS) and confocal microscopy.

A highly efficient rGO grafted MoS2 nanocomposite for dye adsorption and electrochemical detection of hydroquinone in wastewater

Scheme depicting the synthesis and the fabrication of rGO–MoS2 nanocomposite-based enzymatic biosensor for estimation of hydroquinone.

Optimized Degradation and Inhibition of α-glucosidase Activity by Gracilaria lemaneiformis Polysaccharide and Its Production In Vitro

Gracilaria lemaneiformis polysaccharide (GLP) exhibits good physiological activities, and it is more beneficial as it is degraded. After its degradation by hydrogen peroxide combined with vitamin C (H₂O₂-Vc) and optimized by Box–Behnken Design (BBD), a new product of GLP-HV will be generated. While using GLP as control, two products of GLP-H (H₂O₂-treated) and GLP-V (Vc-treated) were also produced. These products chemical characteristics (total sugar content, molecular weight, monosaccharide composition, UV spectrum, morphological structure, and hypolipidemic activity in vitro) were assessed. The results showed that the optimal conditions for H₂O₂-Vc degradation were as follows: H₂O₂-Vc concentration was 18.7 mM, reaction time was 0.5 h, and reaction temperature was 56 °C. The total sugar content of GLP and its degradation products (GLP-HV, GLP-H and GLP-V) were more than 97%, and their monosaccharides are mainly glucose and galactose. The SEM analysis demonstrated that H₂O₂-Vc made the structure loose and broken. Moreover, GLP, GLP-HV, GLP-H, and GLP-V had significantly inhibition effect on α-glucosidase, and their IC₅₀ value were 3.957, 0.265, 1.651, and 1.923 mg/mL, respectively. GLP-HV had the best inhibition effect on α-glucosidase in a dose-dependent manner, which was the mixed type of competitive and non-competitive. It had a certain quenching effect on fluorescence of α-glucosidase, which may be dynamic quenching.

Hierarchical micro- and mesoporous ZIF-8 with core-shell superstructures using colloidal metal sulfates as soft templates for enzyme immobilization

Metal-organic frameworks (MOFs), with large specific surface area and tunable porosity, have gained lots of attention for immobilizing enzymes. However, the intrinsic open channels of most reported MOFs are generally smaller than 2 nm, which significantly prevents the passage of enzymes, and the diffusion efficiency of substrates and products. Here we report a new hierarchical micro-mesoporous zeolitic imidazolate framework-8 (ZIF-8) with core-shell superstructure (HZIF-8) using colloidal hydrated zinc sulfate (ZnSO₄·7H₂O) as a soft template for enzyme immobilization. The ZnSO₄·7H₂O forms an aggregation of colloids due to the self-conglobation effect in methanol, which affords a soft template for the formation of HZIF-8. Cytochrome C (Cyt C) was immobilized in interior of HZIF-8 through entrapment during the formation of HZIF-8. The resultant immobilized Cyt C (Cyt C@HZIF-8) exhibited 4-fold and 3-fold higher activity than free Cyt C and Cyt C encapsulated in conventional microporous ZIF-8 (Cyt C@ZIF-8), respectively. Meanwhile, the Km value of Cyt C@HZIF-8 significantly decreased due to the presence of mesopores compared with Cyt C@ZIF-8, indicating enhanced substrate affinity. After 7 cycles, Cyt C@HZIF-8 still maintained 70% of its initial activity whereas Cyt C@ZIF-8 only retained 10% of its initial activity. Moreover, the obtained HZIF-8 showed outstanding performance in co-immobilization of multi-enzyme for the detection of glucose.

An Up‐to‐Date Review on Alginate Nanoparticles and Nanofibers for Biomedical and Pharmaceutical Applications

Alginate is a naturally occurring polysaccharide commonly derived from brown algae cell walls which possesses unique features that make it extremely promising for several biomedical and pharmaceutical purposes. Alginate biomaterials are indeed nowadays gaining increasing interest in drug delivery and tissue engineering applications owing to their intrinsic biocompatibility, non‐toxicity, versatility, low cost, and ease of functionalization. Specifically, alginate‐based nanostructures show enhanced capabilities with respect to alginate bulk materials in the targeted delivery of drugs and chemotherapies, as well as in helping tissue reparation and regeneration. Hence, it is not surprising that the number of scientific reports related to this topic have rapidly grown in the last decade. With these premises, the present review aims to provide a comprehensive state‐of‐the‐art of the most recent advances in the preparation of alginate‐based nanoparticles and electrospun nanofibers for drug delivery, cancer therapy, and tissue engineering purposes. After a short introduction concerning the general properties and uses of alginate and the concept of nanotechnology, the recent literature is then critically presented to highlight the main advantages of alginate‐based nanostructures. Finally, the current limitations and the future perspectives and objectives are discussed in detail.

Chitosan-based blends for biomedical applications

Polysaccharides are the most abundant naturally available carbohydrate polymers; composed of monosaccharide units covalently connected together. Chitosan is the most widely used polysaccharides because of its exceptional biocompatibility, mucoadhesion, and chemical versatility. However, it suffers from a few drawbacks, e.g. poor mechanical properties and antibacterial activity for biomedical applications. Blending chitosan with natural or synthetic polymers may not merely improve its physicochemical and mechanical properties, but may also improve its bioactivity-induced properties. This review paper summarizes progress in chitosan blends with biodegradable polymers and polysaccharides and their biomedical applications. Blends of chitosan with alginate, starch, cellulose, pectin and dextran and their applications were particularly addressed. The critical and challenging aspects as well as the future ahead of the use of chitosan-based blends were eventually enlightened.