Amine-functionalized magnetic nanoparticles as robust support for immobilization of Lipase

Chitosan decorated magnetic nanobiocatalyst of Bacillus derived α-amylase as a role model for starchy wastewater treatment, detergent additive and textile desizer

In this study, Bacillus tequilensis TB5 α-amylase from rice-milled by-products (rice bran and de-oiled rice bran) was successfully immobilized onto biologically synthesized magnetic nanoparticles fabricated with chitosan (MNP-Ch) and characterized via different biophysical techniques. Furthermore, the study emphasized incorporating this nanostructure framework (MNP@2mgchitosan_DORB-amy and MNP@3mgchitosan_RB-amy) to offer diverse applications, including enzymatic desizing, cleaning starchy stains, and treating synthetic starchy wastewater. An enzyme loading of > 90 % for both enzymes indicated increased binding sites due to the functional moieties of chitosan on the MNP. The Km was 0.28 and 0.31 mg/mL for the immobilized and free forms of DORB-amy, respectively, and 0.18 and 0.27 mg/mL for the immobilized and free forms of RB-amy, respectively. A low Km indicated an increased affinity of MNP-Ch-immobilized forms of enzymes toward the substrate. The performance of both immobilized enzymes improved at a wide range of pH and temperature, which may be attributed to the covalent binding of the enzyme on to the MNP-Ch. The nanobiocatalysts in the detergent act synergistically to fade the starchy stains. Furthermore, an 8-9 TEGEWA scale rating with > 11 % of starch removal was obtained through the biodesizing of starch-sized cotton fabric. The nanobiocatalyst efficiently decomposed starch and liberated 650-670 mg/L of reducing sugar from the synthetic wastewater, therefore offering promising opportunities for its exploration in a wastewater treatment plant. Thus, the study recommends the potential exploration of sturdy matrices like MNP to offer remarkable applications with maximum operational stability, easier recovery, and higher efficiency.

Immobilized lipase enzyme on green synthesized magnetic nanoparticles using Psidium guava leaves for dye degradation and antimicrobial activities

Zinc ferrite nanoparticles (ZnF NPs) were synthesized by a green method using Psidium guava Leaves extract and characterized via structural and optical properties. The surface of ZnF NPs was stabilized with citric acid (CA) by a direct addition method to obtain (ZnF-CA NPs), and then lipase (LP) enzyme was immobilized on ZnF-CA NPs to obtain a modified ZnF-CA-LP nanocomposite (NCs). The prepared sample's photocatalytic activity against Methylene blue dye (MB) was determined. The antioxidant activity of ZnF-CA-LP NCs was measured using 1,1-diphenyl-2-picryl hydrazyl (DPPH) as a source of free radicals. In addition, the antibacterial and antibiofilm capabilities of these substances were investigated by testing them against gram-positive Staphylococcus aureus (S. aureus ATCC 25923) and gram-negative Escherichia coli (E. coli ATCC 25922) bacterial strains. The synthesized ZnF NPs were discovered to be situated at the core of the material, as determined by XRD, HRTEM, and SEM investigations, while the CA and lipase enzymes were coated in this core. The ZnF-CA-LP NCs crystallite size was around 35.0 nm at the (311) plane. Results obtained suggested that 0.01 g of ZnF-CA-LP NCs achieved 96.0% removal of 5.0 ppm of MB at pH 9.0. In-vitro zone of inhibition (ZOI) and minimum inhibitory concentration (MIC) results verified that ZnF-CA-LP NCs exhibited its encouraged antimicrobial activity against S. aureus and E. coli (20.0 ± 0.512, and 27.0 ± 0.651 mm ZOI, respectively) & (1.25, and 0.625 μg/ml MIC, respectively). ZnF-CA-LP NPs showed antibiofilm percentage against S. aureus (88.4%) and E. coli (96.6%). Hence, ZnF-CA-LP NCs are promising for potential applications in environmental and biomedical uses.

Enzyme-triggered approach to reduce water bodies' contamination using peroxidase-immobilized ZnO/SnO2/alginate nanocomposite

Enzyme immobilization on solid support offers advantages over free enzymes by overcoming characteristic limitations. To synthesize new stable and hyperactive nano-biocatalysts (co-precipitation method), ginger peroxidase (GP) was surface immobilized (adsorption) on ZnO/SnO2 and ZnO/SnO2/SA nanocomposite with immobilization efficacy of 94 % and 99 %, respectively. Thereafter, catalytic and biochemical characteristics of free and immobilized GP were investigated by deploying various techniques, i.e., FTIR, PXRD, SEM, and PL. Diffraction peaks emerged at 2θ values of 26°, 33°, 37°, 51°, 31°, 34°, 36°, 56°, indicating the formation of SnO2 and ZnO. The OH stretching of the H2O molecules was attributed to broad peaks between 3200 and 3500 cm-1, whereas ZnO/SnO2 spikes occurred in the 1626-1637 cm-1 range. SnO stretching mode and ZnO terminal vibrational patterns have been verified at corresponding wavelengths of 625 cm-1 and 560 cm-1. Enzyme entrapment onto substrate was verified via interactions between GP and ZnO/SnO2/SA as corroborated by signals beneath 1100 cm-1. GP-immobilized fractions were optimally active at pH 5, 50 °C, and retained maximum activity after storage of 4 weeks at -4 °C. Kinetic parameters were determined by using a Lineweaver-Burk plot and Vmax for free GP, ZnO/SnO2/GP and ZnO/SnO2/SA/GP with guaiacol as a substrate, were found to be 322.58, 49.01 and 11.45 (μM/min) respectively. A decrease in values of Vmax and KM indicates strong adsorption of peroxidase on support and maximum affinity between nano support and enzyme, respectively. For environmental remediation, free ginger peroxidase (GP), ZnO/SnO2/GP and ZnO/SnO2/SA/GP fractions effectively eradicated highly intricate dye. Multiple scavengers had a significant impact on the depletion of the dye. In conclusion, ZnO/SnO2 and ZnO/SnO2/SA nanostructures comprise an ecologically acceptable and intriguing carrier for enzyme immobilization.

Production of a recyclable nanobiocatalyst to synthesize quinazolinone derivatives

Nanobiocatalysts (NBCs) are an emerging innovation that paves the way toward sustainable and eco-friendly endeavors. In the quest for a robust and reusable nanobiocatalyst, herein, we report a nanobiocatalyst, namely CALB@MrGO, developed via immobilizing Candida antarctica lipase B onto the surface of Fe3O4-decorated reduced graphene oxide (MrGO). Next, the enormous potential of the NBC (CALB@MrGO) was checked by employing it to synthesize clinically important quinazolinone derivatives in good to excellent yield (70-95%) using differently substituted aryl aldehydes with 2-aminobenzamide. Further, the synthetic utility and generality of this protocol was proved by setting up a gram-scale reaction, which afforded the product in 87% yield. The green chemistry metrics calculated for the gram-scale reaction those prove the greenness of this protocol.

Polymeric biocompatible iron oxide nanoparticles labeled with peptides for imaging in ovarian cancer

Compared with other nanomaterials, surface-modified iron oxide nanoparticles (IONPs) have gained attraction for cancer therapy applications due to its low toxicity, and long retention time. An innocuous targeting strategy was developed by generation of fluorescein isothiocyanate (FITC)-labeled peptide (growth factor domain (GFD) and somatomedin B domain (SMB)) functionalized, chitosan-coated IONPs (IONPs/C). It can be used to target urokinase plasminogen activator receptor (uPAR), which is a surface biomarker, in ovarian cancer. Binding affinity between uPAR and peptides (GFD and SMB) were revealed by in-silico docking studies. The biophysical characterizations of IONPs, IONPs/C, and IONPs/C/GFD-FITC or SMB-FITC nanoprobes were assessed via Vibrating Sample Magnetometer (VSM), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and Fourier Transform Infrared Spectroscopy (FT-IR). Prussian Blue staining, fluorescence spectroscopy, and fluorescence imaging were performed to confirm the targeting of nanoprobes with the surface receptor uPAR. The combination of IONPs/C/GFD+SMB showed efficient targeting of uPAR in the tumor microenvironment, and thus can be implemented as a molecular magnetic nanoprobe for cancer cell imaging and targeting.

First biocatalytic synthesis of piperidine derivatives via an immobilized lipase-catalyzed multicomponent reaction

A robust and reusable biocatalyst was constructed via immobilization of lipase onto magnetic halloysite nanotubes for the synthesis of piperidine derivatives.

Nanocarriers-based immobilization of enzymes for industrial application

Nanocarriers-based immobilization strategies are a novel concept in the enhancement of enzyme stability, shelf life and efficiency. A wide range of natural and artificial supports have been assessed for their efficacy in enzyme immobilization. Nanomaterials epitomize unique and fascinating matrices for enzyme immobilization. These structures include carbon nanotubes, superparamagnetic nanoparticles and nanofibers. These nano-based supports offer stable attachment of enzymes, thus ensuring their reusability in diverse industrial applications. This review attempts to encompass recent developments in the critical role played by nanotechnology towards the improvement of the practical applicability of microbial enzymes. Nanoparticles are increasingly being used in combination with various polymers to facilitate enzyme immobilization. These endeavors are proving to be conducive for enzyme-catalyzed industrial operations. In recent years the diversity of nanomaterials has grown tremendously, thus offering endless opportunities in the form of novel combinations for various biotransformation experimentations. These nanocarriers are advantageous for both free enzymes and whole-cell immobilization, thus demonstrating to be relatively effective in several fermentation procedures.

Magnetic nanoparticles as versatile carriers for enzymes immobilization: A review

Enzymes are highly efficient biocatalysts and widely employed in biotechnological sectors. However, lack of (re)-purification and efficient recovery of enzymes are among the most critical and challenging aspects, which render them enormously expensive for industrial exploitability. Aiming to tackle these challenges, magnetic nanoparticles (MNPs) have gained a special place as versatile carriers and supporting matrices for immobilization purposes, owing to the exceptional properties of MNPs, such as large surface area, large surface-to-volume ratio, and mobility and high mass transference. More importantly, they can also be easily separated and recovered by applying an external magnetic field. Apart from their biocompatible micro-environment, the utilization of such MNPs represents a noteworthy green chemistry approach, since it lengthens the biocatalyst lifetime through multiple recovery cycles. According to the literature evidence, various modification and/or functionalization approaches have been developed to produce MNPs for the effective immobilization of a broad variety of industrially important enzymes and biomolecules with improved characteristics. Enzymes immobilized on MNPs displayed a wide-working pH and temperature range, as well as, improved thermal and storage stabilities than that of their pristine counterparts. Co-immobilization of multi-enzymes could also be accomplished through nanoparticle-based approaches. This review presents an updated outlook on the development and characterization of MNPs, in particular, iron-based MNPs-derived nano-constructs as support materials for enzyme immobilization.

Polyethylenimine: a very useful ionic polymer in the design of immobilized enzyme biocatalysts

This review discusses the possible roles of polyethylenimine (PEI) in the design of improved immobilized biocatalysts from diverse perspectives.