Enzymes immobilization onto magnetic nanoparticles to improve industrial and environmental applications

Innovative approaches in invertase immobilization: Utilizing green synthesized zinc oxide nanoparticles to improve biochemical properties

Invertase enzyme can effectively improve the taste, color, and durability of these products. Various methods have been proposed to increase the stability and efficiency of enzymes. One of the most important is enzyme immobilization, which can be implemented on different materials. The purpose of this study was to immobilize the invertase enzyme on the surface of green synthesized zinc oxide nanoparticles and to investigate its biochemical properties. The enzyme immobilization was confirmed by SEM and Raman spectroscopy. Then, the biochemical characteristics, such as optimal pH and temperature, thermal stability, and storage stability of free and immobilized enzymes, were determined. The results of SEM showed that the diameter of synthesized nanoparticles was about 60 ± 5 nm. FTIR of immobilized invertase confirmed the immobilization process. The immobilization efficiency was determined to be 72 %. Immobilized enzyme showed higher thermal stability at 40 and 50 °C. Immobilized enzyme could be used 8 times in optimum condition. Also, an Examination of the kinetic parameters of the immobilized enzyme compared with those of the free enzyme showed a decrease in the maximum velocity of the enzyme. It seems that the immobilized invertase has improved characteristics for application in different industries.

Enzyme immobilization with nanomaterials for hydrolysis of lignocellulosic biomass: Challenges and future Perspectives

Enzyme immobilization has emerged as a prodigious strategy in the enzymatic hydrolysis of lignocellulosic biomass (LCB) promising enhanced efficacy and stability of the enzymes. Further, enzyme immobilization on magnetic nanoparticles (MNPs) facilitates the easy recovery and reuse of biocatalysts. This results in the development of a nanobiocatalytic system, that serves as an eco-friendly and inexpensive LCB deconstruction approach. This review provides an overview of nanomaterials used for immobilization with special emphasis on the nanomaterial-enzyme interactions and strategies of immobilization. After the succinct outline of the immobilization procedures and supporting materials, a comprehensive assessment of the catalysis enabled by nanomaterial-immobilized biocatalysts for the conversion and degradation of lignocellulosic biomasses is provided by gathering state-of-the-art examples. The challenges and future directions associated with this technique providing a potential solution in the present article. Insight on the recent advancements in the process of nanomaterial-based immobilization for the hydrolysis of lignocellulosic biomass has also been highlighted in the article.

Magnetic nanosystem a tool for targeted delivery and diagnostic application: Current challenges and recent advancement

Over the last two decades, researchers have paid more attention to magnetic nanosystems due to their wide application in diverse fields. The metal nanomaterials' antimicrobial and biocidal properties make them an essential nanosystem for biomedical applications. Moreover, the magnetic nanosystems could have also been used for diagnosis and treatment because of their magnetic, optical, and fluorescence properties. Superparamagnetic iron oxide nanoparticles (SPIONs) and quantum dots (QDs) are the most widely used magnetic nanosystems prepared by a simple process. By surface modification, researchers have recently been working on conjugating metals like silica, copper, and gold with magnetic nanosystems. This hybridization of the nanosystems modifies the structural characteristics of the nanomaterials and helps to improve their efficacy for targeted drug and gene delivery. The hybridization of metals with various nanomaterials like micelles, cubosomes, liposomes, and polymeric nanomaterials is gaining more interest due to their nanometer size range and nontoxic, biocompatible nature. Moreover, they have good injectability and higher targeting ability by accumulation at the target site by application of an external magnetic field. The present article discussed the magnetic nanosystem in more detail regarding their structure, properties, interaction with the biological system, and diagnostic applications.

Tyrosinase enzyme purification and immobilization from Pseudomonas sp. EG22 using cellulose coated magnetic nanoparticles: characterization and application in melanin production

Melanin is a brown-black pigment with significant roles in various biological processes. The tyrosinase enzyme catalyzes the conversion of tyrosine to melanin and has promising uses in the pharmaceutical and biotechnology sectors. This research aims to purify and immobilize the tyrosinase enzyme from Pseudomonas sp. EG22 using cellulose-coated magnetic nanoparticles. Various techniques were utilized to examine the synthesized nanoparticles, which exhibited a spherical shape with an average diameter of 12 nm and a negative surface potential of - 55.7 mV with a polydispersity index (PDI) of 0.260. Comparing the immobilized magnetic tyrosinase enzyme with the free enzyme, the study's findings showed that the immobilized tyrosinase enzyme had optimal activity at a pH of 6 and a temperature of 35 °C, and its activity increased as the concentration of tyrosine increased. The study investigated the antibacterial and anticancer bioactivity of the enzyme's melanin product and found that it exhibited potential antibacterial activity against a multi-drug resistant strain including S. aureus and E. coli. The produced melanin also demonstrated the potential to decrease cell survival and induce apoptosis in initiation cells.

Enzyme immobilization studied through molecular dynamic simulations

In recent years, simulations have been used to great advantage to understand the structural and dynamic aspects of distinct enzyme immobilization strategies, as experimental techniques have limitations in establishing their impact at the molecular level. In this review, we discuss how molecular dynamic simulations have been employed to characterize the surface phenomenon in the enzyme immobilization procedure, in an attempt to decipher its impact on the enzyme features, such as activity and stability. In particular, computational studies on the immobilization of enzymes using i) nanoparticles, ii) self-assembled monolayers, iii) graphene and carbon nanotubes, and iv) other surfaces are covered. Importantly, this thorough literature survey reveals that, while simulations have been primarily performed to rationalize the molecular aspects of the immobilization event, their use to predict adequate protocols that can control its impact on the enzyme properties is, up to date, mostly missing.

A comprehensive review on the potential of microbial enzymes in multipollutant bioremediation: Mechanisms, challenges, and future prospects

Industrialization and other human activity represent significant environmental hazards. Toxic contaminants can harm a comprehensive platform of living organisms in their particular environments. Bioremediation is an effective remediation process in which harmful pollutants are eliminated from the environment using microorganisms or their enzymes. Microorganisms in the environment often create a variety of enzymes that can eliminate hazardous contaminants by using them as a substrate for development and growth. Through their catalytic reaction mechanism, microbial enzymes may degrade and eliminate harmful environmental pollutants and transform them into non-toxic forms. The principal types of microbial enzymes which can degrade most hazardous environmental contaminants include hydrolases, lipases, oxidoreductases, oxygenases, and laccases. Several immobilizations, genetic engineering strategies, and nanotechnology applications have been developed to improve enzyme performance and reduce pollution removal process costs. Until now, the practically applicable microbial enzymes from various microbial sources and their ability to degrade multipollutant effectively or transformation potential and mechanisms are unknown. Hence, more research and further studies are required. Additionally, there is a gap in the suitable approaches considering toxic multipollutants bioremediation using enzymatic applications. This review focused on the enzymatic elimination of harmful contaminants in the environment, such as dyes, polyaromatic hydrocarbons, plastics, heavy metals, and pesticides. Recent trends and future growth for effectively removing harmful contaminants by enzymatic degradation are also thoroughly discussed.

Immobilized nanoparticles-mediated enzyme therapy; promising way into clinical development

Enzyme (Enz)-mediated therapy indicated a remarkable effect in the treatment of many human cancers and diseases with an insight into clinical phases. Because of insufficient immobilization (Imb) approach and ineffective carrier, Enz therapeutic exhibits low biological efficacy and bio-physicochemical stability. Although efforts have been made to remove the limitations mentioned in clinical trials, efficient Imb-destabilization and modification of nanoparticles (NPs) remain challenging. NP internalization through insufficient membrane permeability, precise endosomal escape, and endonuclease protection following release are the primary development approaches. In recent years, innovative manipulation of the material for Enz immobilization (EI) fabrication and NP preparation has enabled nanomaterial platforms to improve Enz therapeutic outcomes and provide low-diverse clinical applications. In this review article, we examine recent advances in EI approaches and emerging views and explore the impact of Enz-mediated NPs on clinical therapeutic outcomes with at least diverse effects.

Immobilization of Hyperthermostable Carboxylesterase EstD9 from Anoxybacillus geothermalis D9 onto Polymer Material and Its Physicochemical Properties

Carboxylesterase has much to offer in the context of environmentally friendly and sustainable alternatives. However, due to the unstable properties of the enzyme in its free state, its application is severely limited. The present study aimed to immobilize hyperthermostable carboxylesterase from Anoxybacillus geothermalis D9 with improved stability and reusability. In this study, Seplite LX120 was chosen as the matrix for immobilizing EstD9 by adsorption. Fourier-transform infrared (FT-IR) spectroscopy verified the binding of EstD9 to the support. According to SEM imaging, the support surface was densely covered with the enzyme, indicating successful enzyme immobilization. BET analysis of the adsorption isotherm revealed reduction of the total surface area and pore volume of the Seplite LX120 after immobilization. The immobilized EstD9 showed broad thermal stability (10-100 °C) and pH tolerance (pH 6-9), with optimal temperature and pH of 80 °C and pH 7, respectively. Additionally, the immobilized EstD9 demonstrated improved stability towards a variety of 25% (v/v) organic solvents, with acetonitrile exhibiting the highest relative activity (281.04%). The bound enzyme exhibited better storage stability than the free enzyme, with more than 70% of residual activity being maintained over 11 weeks. Through immobilization, EstD9 can be reused for up to seven cycles. This study demonstrates the improvement of the operational stability and properties of the immobilized enzyme for better practical applications.

Can wood-feeding termites solve the environmental bottleneck caused by plastics? A critical state-of-the-art review

The abundance of synthetic polymers has become an ever-increasing environmental threat in the world. The excessive utilization of plastics leads to the accumulation of such recalcitrant pollutants in the environment. For example, during the COVID-19 pandemic, unprecedented demand for personal protective equipment (PPE) kits, face masks, and gloves made up of single-use items has resulted in the massive generation of plastic biomedical waste. As secondary pollutants, microplastic particles (<5 mm) are derived from pellet loss and degradation of macroplastics. Therefore, urgent intervention is required for the management of these hazardous materials. Physicochemical approaches have been employed to degrade synthetic polymers, but these approaches have limited efficiency and cause the release of hazardous metabolites or by-products into the environment. Therefore, bioremediation is a proper option as it is both cost-efficient and environmentally friendly. On the other hand, plants evolved lignocellulose to be resistant to destruction, whereas insects, such as wood-feeding termites, possess diverse microorganisms in their guts, which confer physiological and ecological benefits to their host. Plastic and lignocellulose polymers share a number of physical and chemical properties, despite their structural and recalcitrance differences. Among these similarities are a hydrophobic nature, a carbon skeleton, and amorphous/crystalline regions. Compared with herbivorous mammals, lignocellulose digestion in termites is accomplished at ordinary temperatures. This unique characteristic has been of great interest for the development of a plastic biodegradation approach by termites and their gut symbionts. Therefore, transferring knowledge from research on lignocellulosic degradation by termites and their gut symbionts to that on synthetic polymers has become a new research hotspot and technological development direction to solve the environmental bottleneck caused by synthetic plastic polymers.

A combined treatment of Proteinase K and biosynthesized ZnO-NPs for eradication of dairy biofilm of sporeformers

Biofilms of sporeformers found in the dairy industry are the major contaminants during processing, as they withstand heat and chemical treatment that are used to control microbes. The present work is aimed to remove these resistant forms of bacterial community (biofilm) present in dairy production lines using ecofriendly agents based on proteinase K (Prot-K) coupled with Zinc oxide nanoparticles (ZnO-NPs). Some metal/metal oxide (Ag, CuO and ZnO) NPs were prepared microbially, and ZnO-NPs were characterized as the most effective ones among them. The produced ZnO-NPs were 15-25 nm in size with spherical shape, and FTIR analysis confirmed the presence of proteins and alkanes surrounding particles as capping agents. Application of Prot-K for eradication (removal) of a model biofilm of mixed sporeformers on food-grade stainless steel resulted in an 83% reduction in the absorbance of crystal violet-stained biofilm. When Prot-K was mixed with the biosynthesized NPs ZnO_G240, the reduction increased to 99.19%. This finding could contribute to an efficient cleaning approach combined with CIP to remove the recalcitrant biofilms in dairy production lines.

Environmental Properties and Applications of Biodegradable Starch-Based Nanocomposites

In recent years, the demand for environmental sustainability has caused a great interest in finding novel polymer materials from natural resources that are both biodegradable and eco-friendly. Natural biodegradable polymers can displace the usage of petroleum-based synthetic polymers due to their renewability, low toxicity, low costs, biocompatibility, and biodegradability. The development of novel starch-based bionanocomposites with improved properties has drawn specific attention recently in many applications, including food, agriculture, packaging, environmental remediation, textile, cosmetic, pharmaceutical, and biomedical fields. This paper discusses starch-based nanocomposites, mainly with nanocellulose, chitin nanoparticles, nanoclay, and carbon-based materials, and their applications in the agriculture, packaging, biomedical, and environment fields. This paper also focused on the lifecycle analysis and degradation of various starch-based nanocomposites.

Recent Advances in Nattokinase-Enriched Fermented Soybean Foods: A Review

With the dramatic increase in mortality of cardiovascular diseases (CVDs) caused by thrombus, this has sparked an interest in seeking more effective thrombolytic drugs or dietary nutriments. The dietary consumption of natto, a traditional Bacillus-fermented food (BFF), can reduce the risk of CVDs. Nattokinase (NK), a natural, safe, efficient and cost-effective thrombolytic enzyme, is the most bioactive ingredient in natto. NK has progressively been considered to have potentially beneficial cardiovascular effects. Microbial synthesis is a cost-effective method of producing NK. Bacillus spp. are the main production strains. While microbial synthesis of NK has been thoroughly explored, NK yield, activity and stability are the critical restrictions. Multiple optimization strategies are an attempt to tackle the current problems to meet commercial demands. We focus on the recent advances in NK, including fermented soybean foods, production strains, optimization strategies, extraction and purification, activity maintenance, biological functions, and safety assessment of NK. In addition, this review systematically discussed the challenges and prospects of NK in actual application. Due to the continuous exploration and rapid progress of NK, NK is expected to be a natural future alternative to CVDs.

Comparative study of poly tannic acid functionalized magnetic particles before and after modification for immobilized penicillin G acylase

In this work, Fe₃O₄ nanoparticles (NPs) was synthesized by inverting microemulsion method. After that, based on the physical and chemical properties of tannic acid (TA), poly tannic acid (PTA) was coated on Fe₃O₄ NPs surface. Fe₃O₄ NPs coated with PTA, on the one hand, was used to immobilize Penicillin G acylase (PGA) by physical adsorption. On the other hand, it was modified by glutaraldehyde (GA). GA grafting rate (G_r-GA) was optimized, and the G_r-GA was 30.0% under the optimum conditions. Then, through the Schiff base reaction between the glutaraldehyde group and PGA amino group, this covalent immobilization of PGA was further realized under mild conditions. Finally, the structures of every stage of magnetic composites were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibration magnetometer (VSM) and transmission electron microscopy (TEM), respectively. The results indicated that the enzyme activity (EA), enzyme activity recovery (EAR) and maximum load (ELC) of the immobilized PGA were 26843 U/g, 80.2% and 125 mg/g, respectively. Compared to the physical immobilization of PGA by only coating PTA nanoparticles, further modified nanoparticles by GA showed higher catalytic stability, reusability and storage stability.

Exoproduction and Biochemical Characterization of a Novel Serine Protease from Ornithinibacillus caprae L9T with Hide-Dehairing Activity

This study is the first report on production and characterization of the enzyme from an Ornithinibacillus species. A 4.2-fold increase in the extracellular protease (called L9^T) production from Ornithinibacillus caprae L9^T was achieved through the one-factor-at-a-time approach and response surface methodological optimization. L9^T protease exhibited a unique protein band with a mass of 25.9 kDa upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This novel protease was active over a range of pH (4-13), temperatures (30-80°C) and salt concentrations (0-220 g/l), with the maximal activity observed at pH 7, 70°C and 20 g/l NaCl. Proteolytic activity was upgraded in the presence of Ag⁺, Ca²⁺ and Sr²⁺, but was totally suppressed by 5 mM phenylmethylsulfonyl fluoride, which suggests that this enzyme belongs to the serine protease family. L9^T protease was resistant to certain common organic solvents and surfactants; particularly, 5 mM Tween 20 and Tween 80 improved the activity by 63 and 15%, respectively. More importantly, L9^T protease was found to be effective in dehairing of goatskins, cowhides and rabbit-skins without damaging the collagen fibers. These properties confirm the feasibility of L9^T protease in industrial applications, especially in leather processing.

Insights on sustainable approaches for production and applications of value added products

The increasing demand for the development of sustainable strategies to utilize and process agro-industrial residues paves new paths for exploring innovative approaches in this area. Biotechnology based microbial transformations provide efficient, low cost and sustainable approaches for the production of value added products. The use of organic rich residues opens new avenues for the production of enzymes, pigments, biofuels, bioactive compounds, biopolymers etc. with vast industrial and therapeutic applications. Innovative technologies like strain improvement, enzyme immobilization, genome editing, morphological engineering, ultrasound/supercritical fluid/pulse electric field extraction, etc. can be employed. These will be helpful in achieving significant improvement in qualitative and quantitative parameters of the finished products. The global trend for the valorisation of biowaste has boosted the commercialization of these products which has transformed the markets by providing new investment opportunities. The upstream processing of raw materials using microbes poses a limitation in terms of product development and recovery which can be overcome by modifying the bioreactor design, physiological parameters or employing alternate technologies which will be discussed in this review. The other problems related to the processes include product stability, industrial applicability and cost competitiveness which needs to be addressed. This review comprehensively discusses the recent progress, avenues and challenges in the approaches aimed at valorisation of agro-industrial wastes along with possible opportunities in the bioeconomy.

Effective utilization of magnetic nano-coupled cloned β-xylanase in saccharification process

The β-xylanase gene (DCE06_04615) with 1041 bp cloned from Thermotoga naphthophila was expressed into E. coli BL21 DE3. The cloned β-xylanase was covalently bound to iron oxide magnetic nanoparticles coated with silica utilizing carbodiimide. The size of the immobilized MNPs (50 nm) and their binding with β-xylanase were characterized by Fourier-transform electron microscopy (FTIR) (a change in shift particularly from C–O to C–N) and transmission electron microscopy (TEM) (spherical in shape and 50 nm in diameter). The results showed that enzyme activity (4.5 ± 0.23 U per mL), thermo-stability (90 °C after 4 hours, residual activity of enzyme calculated as 29.89% ± 0.72), pH stability (91% ± 1.91 at pH 7), metal ion stability (57% ± 1.08 increase with Ca²⁺), reusability (13 times) and storage stability (96 days storage at 4 °C) of the immobilized β-xylanase was effective and superior. The immobilized β-xylanase exhibited maximal enzyme activity at pH 7 and 90 °C. Repeated enzyme assay and saccharification of pretreated rice straw showed that the MNP-enzyme complex exhibited 56% ± 0.76 and 11% ± 0.56 residual activity after 8 times and 13 times repeated usage. The MNP-enzyme complex showed 17.32% and 15.52% saccharification percentage after 1^st and 8^th time usage respectively. Immobilized β-xylanase exhibited 96% residual activity on 96 days' storage at 4 °C that showed excellent stability.

The β-xylanase gene (DCE06_04615) with 1041 bp cloned from Thermotoga naphthophila was expressed into E. coli BL21 DE3.

Magnetically Agitated Nanoparticle-Based Batch Reactors for Biocatalysis with Immobilized Aspartate Ammonia-Lyase

In this study, we investigated the influence of different modes of magnetic mixing on effective enzyme activity of aspartate ammonia-lyase from Pseudomonas fluorescens immobilized onto epoxy-functionalized magnetic nanoparticles by covalent binding (AAL-MNP). The effective specific enzyme activity of AAL-MNPs in traditional shake vial method was compared to the specific activity of the MNP-based biocatalyst in two devices designed for magnetic agitation. The first device agitated the AAL-MNPs by moving two permanent magnets at two opposite sides of a vial in x-axis direction (being perpendicular to the y-axis of the vial); the second device unsettled the MNP biocatalyst by rotating the two permanent magnets around the y-axis of the vial. In a traditional shake vial, the substrate and biocatalyst move in the same direction with the same pattern. In magnetic agitation modes, the MNPs responded differently to the external magnetic field of two permanent magnets. In the axial agitation mode, MNPs formed a moving cloud inside the vial, whereas in the rotating agitation mode, they formed a ring. Especially, the rotating agitation of the MNPs generated small fluid flow inside the vial enabling the mixing of the reaction mixture, leading to enhanced effective activity of AAL-MNPs compared to shake vial agitation.

Designing of Nanomaterials-Based Enzymatic Biosensors: Synthesis, Properties, and Applications

Among the many biological entities employed in the development of biosensors, enzymes have attracted the most attention. Nanotechnology has been fostering excellent prospects in the development of enzymatic biosensors, since enzyme immobilization onto conductive nanostructures can improve characteristics that are crucial in biosensor transduction, such as surface-to-volume ratio, signal response, selectivity, sensitivity, conductivity, and biocatalytic activity, among others. These and other advantages of nanomaterial-based enzymatic biosensors are discussed in this work via the compilation of several reports on their applications in different industrial segments. To provide detailed insights into the state of the art of this technology, all the relevant concepts around the topic are discussed, including the properties of enzymes, the mechanisms involved in their immobilization, and the application of different enzyme-derived biosensors and nanomaterials. Finally, there is a discussion around the pressing challenges in this technology, which will be useful for guiding the development of future research in the area.

Biochemical and thermodynamic characteristics of a new serine protease from Mucor subtilissimus URM 4133

A protease from the fungus Mucor subtilissimus URM 4133, capable of producing bioactive peptides from goat casein, was purified. SDS-PAGE and zymography showed a molecular mass of 30 kDa. The enzyme was active and stable in a wide pH range (6.0–10.5) and (5.0–10.5), respectively. Optimum temperature was at 45–50 °C and stability was above 80 % (40 °C/2 h). Activity was not influenced by ions or organic substances (Triton, Tween, SDS and DMSO), but was completely inhibited by PMSF, suggesting that it belongs to the serine protease family. The Km and Vmax were 2.35 mg azocasein.mL-1 and 333.33 U.mg protein-1, respectively. Thermodynamic parameters of irreversible denaturation (40–60 °C) were enthalpy 123.63 – 123.46 kJ.mol-1, entropy 120.24–122.28 kJ.mol-1 and Gibbs free energy 85.97 – 82.45 kJ.mol-1. Any peptide sequences compatible with this protease were found after analysis by MALDI-TOF, which suggests that it is a new serine protease.