Immobilization of lipase onto novel constructed polydopamine grafted multiwalled carbon nanotube impregnated with magnetic cobalt and its application in synthesis of fruit flavours

Immobilization of pancreatin based on ultrasound-assisted polydopamine functionalized magnetic porous chitosan for the detoxification of ochratoxin A in wine

Ochratoxin A (OTA) is a mycotoxin that globally contaminates fruits and their products. Since OTA have a huge negative impact on health hazards and economic losses, it is imperative to establish an effective and safe strategy for detoxification. Here, pancreatin was immobilized on the surface of polydopamine functionalized magnetic porous chitosan (MPCTS@ PDA) for the degradation of OTA. Compared with free pancreatin, MPCTS@ PDA@ pancreatin displayed excellent thermal stability, acid resistance, storage stability and OTA detoxification in wine (>58%). Moreover, the MPCTS@ PDA@ pancreatin retained 43% initial activity after 8 reuse cycles. There was no significant change in the quality of wine after MPCTS@ PDA@ pancreatin treatment. Moreover, it did not exhibit cytotoxicity which facilitated its application in wine. These results demonstrated that MPCTS@ PDA@ pancreatin can be used as a highly effective biocatalysate for OTA detoxification in wine.

An Alternative Approach to Plastic Recycling: Fabrication and Characterization of rPET/CA Nanofiber Carriers to Enhance Porcine Pancreatic Lipase Stability Properties

In response to the increasing demand for sustainable technologies, this study presents a novel approach to plastic recycling. In this study, a method was presented to produce nanofiber carriers by electrospinning using recycled poly(ethylene terephthalate) (rPET) obtained from wastewater bottles and cellulose acetate (CA). These carriers serve as a platform for immobilized porcine pancreatic lipase (PPL), aiming to enhance its stability. The production parameters for the rPET/CA nanofibers were found to be an rPET concentration of 15% (v/v), a CA concentration of 6% (v/v), an electrical voltage of 13 kV, a needle-collector distance of 18 cm, and an injection speed of 0.1 mL/h. The nanofiber structure and morphology were assessed by using attenuated total reflectance-infrared Fourier transform infrared (ATR-FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) analyses. Then, PPL was immobilized onto the nanofibers through adsorption and cross-linking methods. The optimum temperature for free PPL was determined to be 30 °C, and the optimum temperature for PPL immobilized on rPET/CA was determined to be 40 °C. It was observed that, especially under acidic conditions, after the immobilization process, PPL immobilized rPET/CA nanofibers became more resistant to pH changes than free PLL. Furthermore, the immobilized PPL exhibited improved pH stability, reusability, and thermal stability compared to its free counterpart. This innovative approach not only contributes to plastic waste reduction but also opens new avenues for enzyme immobilization with potential applications in biocatalysis and wastewater treatment.

Green nanobiocatalysts: enhancing enzyme immobilization for industrial and biomedical applications

Nanobiocatalysts (NBCs), which merge enzymes with nanomaterials, provide a potent method for improving enzyme durability, efficiency, and recyclability. This review highlights the use of eco-friendly synthesis methods to create sustainable nanomaterials for enzyme transport. We investigate different methods of immobilization, such as adsorption, ionic and covalent bonding, entrapment, and cross-linking, examining their pros and cons. The decreased environmental impact of green-synthesized nanomaterials from plants, bacteria, and fungi is emphasized. The review exhibits the various uses of NBCs in food industry, biofuel production, and bioremediation, showing how they can enhance effectiveness and eco-friendliness. Furthermore, we explore the potential impact of NBCs in biomedicine. In general, green nanobiocatalysts are a notable progression in enzyme technology, leading to environmentally-friendly and effective biocatalytic methods that have important impacts on industrial and biomedical fields.

Artificial antibody-antigen-directed immobilization of lipase for consecutive catalytic synthesis of ester: Benzyl acetate case study

A strategy based on artificial antibody-antigen recognition was proposed for the specific directed immobilization of lipase. The artificial antibody was synthesized using catechol as a template, α-methacrylic acid as a functional monomer, and Fe3O4 as the matrix material. Lipase was modified with 3,4-dihydroxybenzaldehyde as an artificial antigen. The artificial antibody can specifically recognize catechol fragment in the enzyme structure to achieve the immobilization of lipase. The immobilization amount, yield, specific activity, and immobilized enzyme activity were 13.2 ± 0.2 mg/g, 78.9 ± 0.4 %, 7.9 ± 0.2 U/mgprotein, and 104.6 ± 1.7 U/gcarrier, respectively. Moreover, the immobilized lipase exhibited strong reusability and regeneration ability. Additionally, the immobilized lipase successfully catalyzed the synthesis of benzyl acetate and demonstrated robust continuous catalytic activity. These results fully demonstrate the feasibility of the proposed artificial antibody-antigen-directed immobilization of lipase.

Advancements in enzyme immobilization on magnetic nanomaterials: toward sustainable industrial applications

Enzymes are widely used in biofuels, food, and pharmaceuticals. The immobilization of enzymes on solid supports, particularly magnetic nanomaterials, enhances their stability and catalytic activity. Magnetic nanomaterials are chosen for their versatility, large surface area, and superparamagnetic properties, which allow for easy separation and reuse in industrial processes. Researchers focus on the synthesis of appropriate nanomaterials tailored for specific purposes. Immobilization protocols are predefined and adapted to both enzymes and support requirements for optimal efficiency. This review provides a detailed exploration of the application of magnetic nanomaterials in enzyme immobilization protocols. It covers methods, challenges, advantages, and future perspectives, starting with general aspects of magnetic nanomaterials, their synthesis, and applications as matrices for solid enzyme stabilization. The discussion then delves into existing enzymatic immobilization methods on magnetic nanomaterials, highlighting advantages, challenges, and potential applications. Further sections explore the industrial use of various enzymes immobilized on these materials, the development of enzyme-based bioreactors, and prospects for these biocatalysts. In summary, this review provides a concise comparison of the use of magnetic nanomaterials for enzyme stabilization, highlighting potential industrial applications and contributing to manufacturing optimization.

Recent insight into the advances and prospects of microbial lipases and their potential applications in industry

Enzymes play a crucial role in various industrial sectors. These biocatalysts not only ensure sustainability and safety but also enhance process efficiency through their unique specificity. Lipases possess versatility as biocatalysts and find utilization in diverse bioconversion reactions. Presently, microbial lipases are gaining significant focus owing to the rapid progress in enzyme technology and their widespread implementation in multiple industrial procedures. This updated review presents new knowledge about various origins of microbial lipases, such as fungi, bacteria, and yeast. It highlights both the traditional and modern purification methods, including precipitation and chromatographic separation, the immunopurification technique, the reversed micellar system, the aqueous two-phase system (ATPS), and aqueous two-phase flotation (ATPF), moreover, delves into the diverse applications of microbial lipases across several industries, such as food, vitamin esters, textile, detergent, biodiesel, and bioremediation. Furthermore, the present research unveils the obstacles encountered in employing lipase, the patterns observed in lipase engineering, and the application of CRISPR/Cas genome editing technology for altering the genes responsible for lipase production. Additionally, the immobilization of microorganisms' lipases onto various carriers also contributes to enhancing the effectiveness and efficiencies of lipases in terms of their catalytic activities. This is achieved by boosting their resilience to heat and ionic conditions (such as inorganic solvents, high-level pH, and temperature). The process also facilitates the ease of recycling them and enables a more concentrated deposition of the enzyme onto the supporting material. Consequently, these characteristics have demonstrated their suitability for application as biocatalysts in diverse industries.

Recent applications and future prospects of magnetic biocatalysts

Magnetic biocatalysts combine magnetic properties with the catalytic activity of enzymes, achieving easy recovery and reuse in biotechnological processes. Lipases immobilized by magnetic nanoparticles dominate. This review covers an advanced bibliometric analysis and an overview of the area, elucidating research advances. Using WoS, 34,949 publications were analyzed and refined to 450. The prominent journals, countries, institutions, and authors that published the most were identified. The most cited articles showed research hotspots. The analysis of the themes and keywords identified five clusters and showed that the main field of research is associated with obtaining biofuels derived from different types of sustainable vegetable oils. The overview of magnetic biocatalysts showed that these materials are also employed in biosensors, photothermal therapy, environmental remediation, and medical applications. The industry shows a significant interest, with the number of patents increasing. Future studies should focus on immobilizing new lipases in unique materials with magnetic profiles, aiming to improve the efficiency for various biotechnological applications.

Catechol-tetraethylenepentamine co-deposition modified cellulose filter paper for α-glucosidase immobilization and inhibitor screening from traditional Chinese medicine

Cellulose filter paper (CFP) is expected to be an ideal carrier for enzyme immobilization due to its sustainability and biocompatibility. However, the interaction between the carrier and enzyme might change the spatial conformation of the enzyme and its microenvironment, and thus the flexibility of the enzyme molecule or the transport of the substrate to the active site would be hampered. In this work, a two-component system of catechol and tetraethylene pentamine was used to replace dopamine, and a polydopamine-like composite layer was deposited on the surface of CFP to introduce amino groups, which was similar to the self-polymerization-adhesion behavior of dopamine. Using polyethylene glycol diglycidyl ether with flexible spacer arms as the cross-linking agent, α-glucosidase was covalently bonded to amino-modified CFP through an epoxy ring-opening reaction. The immobilized α-glucosidase exhibited greater tolerance to pH and high temperature. After 10 repeated uses, the immobilized α-glucosidase maintained relatively high enzyme activity. Its kinetic behavior was investigated to illustrate the reliability for enzyme inhibitor screening. Finally, a screening method combining an immobilized enzyme and capillary electrophoresis analysis was proposed and applied to screening inhibitors from 11 kinds of traditional Chinese medicines, among which Chebulae Fructus, Phyllanthi Fructus and Terminaliae Relliricae Fructus exhibited strong enzyme inhibitory activities.

Construction of a biomimetic core-shell PDA@Lac bioreactor from intracellular laccase as a nano-confined biocatalyst for decolorization

Enzymes immobilized on the surface of the carriers are difficult to maintain their conformation and high activity due to the influence of the external harsh environments. A biomimetic core-shell PDA@Lac bioreactor was constructed by depositing polydopamine (PDA) on the surface of the recombinant Escherichia coli with CotA laccase gene, and releasing intracellular laccase into the PDA shell using ultrasound to break the cell wall of the bacteria. The bioreactor provided a nano-confined environment for the laccase and accelerated the mass and electron transfer in the volume-confined space, with a 2.77-fold increase in Km compared with the free laccase. Since there was no barrier of the cell wall, the crystal violet dye can enter the bioreactor to participate in the enzymatic reaction. As a result, PDA@Lac achieved excellent decolorization performance even without ABTS as an electron mediator. Moreover, the cytoplasmic solution retained in the PDA shell promoted the enzyme's tolerance to pH, temperature and harsh environments. In addition to PDA encapsulation, carbonyl and -NH₂ groups of PDA were bound covalently with -NH₂ and -COOH on the laccase in the PDA@Lac, resulting in an extremely high laccase loading of 817.59 mg/g. Also, the relative activity of the bioreactor maintained approximately 75% after 10 cycles of reuse. In addition, the protection of the PDA shell increased the resistance of laccase to UV irradiation. This work provides a novel method of laccase immobilization for application in wastewater treatment.

N-terminal lid swapping contributes to the substrate specificity and activity of thermophilic lipase TrLipE

TrLipE is a thermophilic lipase that has potential commercial applications because of its catalytic ability under extreme conditions. Consistent with most lipases, the lid of TrLipE is located over the catalytic pocket, controls the substrate channel to the active center, and regulates the substrate specificity, activity, and stability of the enzyme through conformational changes. TrLipE from Thermomicrobium roseum has potential industrial applications, which is hindered by its weak enzymatic activity. Here, 18 chimeras (TrL1-TrL18) were reconstructed by N-terminal lid swapping between TrLipE and structurally similar enzymes. The results showed that the chimeras had a similar pH range and optimum pH as wild TrLipE but a narrower temperature range of 40-80°C, and TrL17 and the other chimeras showed lower optimum temperatures of 70°C and 60°C, respectively. In addition, the half-lives of the chimeras were lower than those of TrLipE under optimum temperature conditions. Molecular dynamics simulations indicated that chimeras had high RMSD, RMSF, and B-factor values. When p-nitrophenol esters with different chains were used as substrates, compared with TrLipE, most of the chimeras had a low K_m and high k_cat value. The chimeras TrL2, TrL3, TrL17, and TrL18 could specifically catalyze the substrate 4-nitrophenyl benzoate, with TrL17 showing the highest k_cat/K_m value of 363.88 ± 15.83 L⋅min^-1⋅mmol^-1. Mutants were then designed by investigating the binding free energies of TrL17 and 4-nitrophenyl benzoate. The results indicated that single, double, and triple substitution variants (M89W and I206N; E33W/I206M and M89W/I206M; and M89W/I206M/L21I and M89W/I206N/L21I, respectively) presented approximately 2- to 3-fold faster catalysis of 4-nitrophenyl benzoate than the wild TrL17. Our observations will facilitate the development of the properties and industrial applications of TrLipE.

A systematic review about affinity tags for one-step purification and immobilization of recombinant proteins: integrated bioprocesses aiming both economic and environmental sustainability

The present study reviewed and discussed the promising affinity tags for one-step purification and immobilization of recombinant proteins. The approach used to structure this systematic review was The Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) methodology. The Scopus and Web of Science databases were used to perform the bibliographic survey by which 267 articles were selected. After the inclusion/exclusion criteria and the screening process, from 25 chosen documents, we identified 7 types of tags used in the last 10 years, carbohydrate-binding module tag (CBM), polyhistidine (His-tag), elastin-like polypeptides (ELPs), silaffin-3-derived pentalysine cluster (Sil3k tag), N-acetylmuramidase (AcmA tag), modified haloalkane dehalogenase (HaloTag®), and aldehyde from a lipase polypeptide (Aldehyde tag). The most used bacterial host for expressing the targeted protein was Escherichia coli and the most used expression vector was pET-28a. The results demonstrated two main immobilization and purification methods: the use of supports and the use of self-aggregating tags without the need of support, depending on the tag used. Besides, the chosen terminal for cloning the tag proved to be very important once it could alter enzyme activity. In conclusion, the best tag for protein one-step purification and immobilization was CBM tag, due to the eco-friendly supports that can be provided from industry wastes, the fast immobilization with high specificity, and the reduced cost of the process.

Dual-target affinity analysis and separation of α-amylase and α-glucosidase inhibitors from Morus alba leaves using a magnetic bifunctional immobilized enzyme system

Morus alba leaves are a natural product with great antidiabetic potential. However, the therapeutic efficacy of natural products is usually achieved through the interaction of active compounds with specific targets. Among them, active compounds with multi-target therapeutic functions are more effective than single-target enzymes. In this study, a bienzyme system was constructed by co-immobilizing α-amylase and α-glucosidase onto Fe₃ O₄ for affinity screening of dual-target active components in the complex extract from M. alba leaves. As a result, a potential active compound was selectively screened by ligand fishing, separated by high-speed countercurrent chromatography using a solvent system of ethyl acetate-n-butanol-water (3:2:5, v/v), and identified as rutin. In addition, the result of molecular docking showed that rutin could interact with the active center of α-amylase and α-glucosidase through multiple hydrogen bonds, van der Waals forces, etc. to play an inhibitory role. These results demonstrate the effectiveness of the polydopamine magnetically immobilized bienzyme system for dual-target affinity screening of active substances. This study not only reveals the chemical basis of the antidiabetic activity of M. alba leaves from a dual-target perspective, but also promotes the progress of multitarget affinity screening.

Covalent immobilization of lipase on an ionic liquid-functionalized magnetic Cu-based metal-organic framework with boosted catalytic performance in flavor ester synthesis

Enzymatic esterification plays an important role in the fields of chemistry and biotechnology. In this study, lipase was immobilized on an ionic liquid (IL)-modified magnetic metal-organic framework (MOF) and used to synthesize isoamyl acetate. The immobilized lipase (PPL-ILs/Fe₃O₄@MOF) showed 2.1-fold and 1.8-fold higher activity compared to the free and immobilized lipase without ILs (PPL-Fe₃O₄@MOF), respectively. In addition, the anti-denaturant ability and reusability of the PPL-ILs/Fe₃O₄@MOF were also higher than those of other samples. The ester yield reached 75.1% when the biocatalyst was used to synthesize isoamyl acetate in hexane. The synthesized supports supplied a good microenvironment for the immobilized lipase through multiple interactions. Results of the structural analysis showed that the conformation state of lipase molecules changed after immobilization. The magnetism of the prepared biocatalyst makes it easy to recycle so that PPL-ILs/Fe₃O₄@MOF maintained 70.2% of the initial activity after eight cycles. The prepared composite materials exhibited good potential in lipase immobilization with enhanced catalytic ability and stability.

A comprehensive review on bio-mimicked multimolecular frameworks and supramolecules as scaffolds for enzyme immobilization

Immobilization depicts a propitious route to optimize the catalytic performances, efficient recovery, minimizing autocatalysis, and also augment the stabilities of enzymes, particularly in unnatural environments. In this opinion, supramolecules and multimolecular frameworks have captivated immense attention to achieve profound controllable interactions between enzyme molecules and well-defined natural or synthetic architectures to yield protein bioconjugates with high accessibility for substrate binding and enhanced enantioselectivities. This scholastic review emphasizes the possibilities of associating multimolecular complexes with biological entities via several types of interactions, namely covalent interactions, host-guest complexation, π - π ${\rm{\pi }}-{\rm{\pi }}$ interactions, intra/inter hydrogen bondings, electrostatic interactions, and so forth offers remarkable applications for the modulations of enzymes. The potential synergies between artificial supramolecular structures and biological systems are the primary concern of this pedagogical review. The majority of the research primarily focused on the dynamic biomolecule-responsive supramolecular assemblages and multimolecular architectures as ideal platforms for the recognition and modulation of proteins and cells. Embracing sustainable green demeanors of enzyme immobilizations in a quest to reinforce site-selectivity, catalytic efficiency, and structural integrality of enzymes are the contemporary requirements of the biotechnological sectors that instigate the development of novel biocatalytic systems.

Industrial applications of fungal lipases: a review

Fungal lipases (triacylglycerol acyl hydrolases EC 3.1.1.3) are significant industrial enzymes and have several applications in a number of industries and fields. Fungal lipases are found in several species of fungi and yeast. These enzymes are carboxylic acid esterases, categorized under the serine hydrolase family, and do not require any cofactor during the catalyzing of the reactions. It was also noticed that processes including the extraction and purification of lipases from fungi are comparatively easier and cheaper than other sources of lipases. In addition, fungal lipases have been classified into three chief classes, namely, GX, GGGX, and Y. Fungal lipases have applications not only in the hydrolysis of fats and oils (triglycerides) but are also involved in synthetic reactions such as esterification, acidolysis, alcoholysis, interesterification, and aminolysis. The production and activity of fungal lipases are highly affected by the carbon source, nitrogen source, temperature, pH, metal ions, surfactants, and moisture content. Therefore, fungal lipases have several industrial and biotechnological applications in many fields such as biodiesel production, ester synthesis, production of biodegradable biopolymers, formulations of cosmetics and personal care products, detergent manufacturing, degreasing of leather, pulp and paper production, textile industry, biosensor development, and drug formulations and as a diagnostic tool in the medical sector, biodegradation of esters, and bioremediation of wastewater. The immobilization of fungal lipases onto different carriers also helps in improving the catalytic activities and efficiencies of lipases by increasing thermal and ionic stability (in organic solvents, high pH, and temperature), being easy to recycle, and inducing the volume-specific loading of the enzyme onto the support, and thus, these features have proved to be appropriate for use as biocatalysts in different sectors.

Surface Modification of Magnetic ZIF-90 Nanoparticles Improves the Microenvironment of Immobilized Lipase and Its Application in Esterification

Interactions of enzymes with supports significantly affect the activity and stability of immobilized enzymes. Herein, amino-functionalized ionic liquid (IL)-grafted magnetic zeolitic imidazolate framework-90 (MZIF-90) was prepared and used to immobilize porcine pancreatic lipase (PPL). The nanocomposites were fully characterized; meanwhile, the interactions between ILs and ZIF-90 were calculated based on density functional theory. The prepared biocatalyst (PPL-ILs/MZIF-90) had a lipase loading of 178.3 mg/g and hydrolysis activity up to 287.5 U/g. When the biocatalyst was used to synthesize isoamyl acetate, the reaction media, molar ratio of alcohol/acid, temperature, and reaction time were optimized. Under the optimized reaction conditions (in hexane, alcohol/acid = 3:1, under 45 °C, reacted for 9 h), the ester yield reached 85.5%. The results of the stability test showed that PPL-ILs/MZIF-90 retained 88.7% of the initial activity after storing for 35 days and 92.5% of the initial activity after reusing for seven cycles for synthesizing isoamyl acetate. Moreover, the secondary structure analysis showed that the synthesized supports protected the active conformation of immobilized lipase, which lead to the enhanced catalytic performance. Additionally, the biocatalyst can be easily separated with a magnet, which facilitated the reusability. This study provides insights regarding the application of metal organic framework composites in the field of enzyme catalysis.

Hotspots and Mechanisms of Action of the Thermostable Framework of a Microbial Thermolipase

The lipase TrLipB from Thermomicrobium roseum is highly thermostable. However, its thermostable skeleton and mechanism of action should be investigated for industrial applications. Toward this, TrLipB was crystallized using the hanging-drop vapor diffusion method and subjected to X-ray diffraction at 2.0 Å resolution in this study. The rigid sites, such as the prolines on the relatively flexible loops on the enzyme surface, were scanned. Soft substitutions of these sites were designed using both molecular dynamics (MD) simulation and site-directed mutagenesis. The thermostability of several substitutions decreased markedly, while the catalytic efficiencies of the P9G, P127G, P194G, and P300G mutants reduced substantially; additionally, the thermostable framework of the double mutant, P194G/P300G, was considerably perturbed. However, the substitutions on the lid of the enzyme, including P49G and P48G, promoted the catalytic efficiency to approximately 150% and slightly enhanced the thermostability below 80 °C. In MD simulations, the P100G, P194G, P100G/P194G, P194G/P300G, and P100G/P194G/P300G mutants showed high B-factors and RMSD values, whereas the secondary structures, radius of gyration, H-bonds, and solvent accessible surface areas of these mutants were markedly affected. Our observations will assist in understanding the natural framework of a stable lipase, which might contribute to its industrial applications.

Immobilization of Rhizomucor miehei lipase on magnetic multiwalled carbon nanotubes towards the synthesis of structured lipids rich in sn-2 palmitic acid and sn-1,3 oleic acid (OPO) for infant formula use

Nowadays, breast milk is considered as the ideal food for infants owing to the most common oleic acid-palmitic acid-oleic acid (OA-PA-OA) fatty acid distribution of the human milk fat (HMF). This study reports the synthesis of 1,3-dioleoyl-2-palmotoylglycerol (OPO)-rich human milk fat substitutes in a two-step enzymatic acidolysis reaction with Rhizomucor miehei lipase (RML) immobilized on magnetic multi-walled carbon nanotubes(mMWCNTs). The immobilized RML (RML-mMWCNTs) showed better thermal and pH stability, convenient recovery and reusability than the free soluble form. Under optimized reaction conditions (1:8 tripalmitin (PPP)/OA, 10%wt. enzyme, 50 °C, 5 h), PA content at the sn-2 position and OA incorporation at the sn-1,3 positions reached 93.46% and 59.54%, respectively. Comparison tests have also showed that RML-mMWCNTs has better catalytic activity and reusability than the commercial lipase Lipozyme RM IM. The results suggest that RML-mMWCNTs is a promising biocatalyst for the synthesis of OPO-rich TAGs with potential use in infant formulas.

Bioinspired Lipase Immobilized Membrane for Improving Hesperidin Lipophilization

Lipophilization is a promising way to improve the bioavailability of flavonoids. However, the traditional enzymatic esterification methods are time-consuming, and present low yields and purity. Herein, a novel membrane-based lipophilization technology-bioinspired lipase immobilized membranes (BLIMs), including CAL-B@PES, CAL-B@PDA/PES and GA/CAL-B@PDA/PES- were fabricated to improve the antioxidant flavanone glycoside hesperidin lipophilization. Via reverse filtration, PDA coating and GA crosslinking, Candida antarctica lipase B (CAL-B) was stably immobilized on membrane to fabricate BLIMs. Among the three BLIMs, GA/CAL-B@PDA/PES had the greatest enzyme activity and enzyme loading, the strongest tolerance of changes in external environmental conditions (temperatures, pH, heating time, storage time and numbers of cycles) and the highest hesperidin esterification efficiency. Moreover, the optimal operating condition for GA/CAL-B@PDA/PES fabrication was the CAL-B concentration of 0.36 mg/mL, operation pressure of 2 bar, GA concentration of 5% and crosslinking time of 1 h. Afterwards, the hesperidin esterification process did not affect the micromorphology of BLIM, but clearly improved the BLIM permeability and esterified product efficiency. The present study reveals the fabrication mechanism of BLIMs and offers insights into the optimizing strategy that governs the membrane-based lipophilization technology process.

Producing Natural Flavours from Isoamyl Alcohol and Fusel Oil by Using Immobilised Rhizopus oryzae Lipase

Enzymatic synthesis of short-chain esters (flavours) might enable their labelling as natural, increasing their value. Covalently immobilised Rhizopus oryzae lipase (EO-proROL) was used to synthesise isoamyl butyrate and acetate. In cyclohexane, the best performer reaction solvent, 1.8 times higher yield of isoamyl butyrate (ca. 100%) than isoamyl acetate (ca. 55%) was obtained. Optimum initial acid concentration (410 mM) and acid:alcohol mole ratio (0.5) were established by a central composite rotatable design to maximise isoamyl butyrate single-batch and cumulative production with reused enzyme. These conditions were used to scale up the esterification (150 mL) and to assess yield, initial esterification rate, productivity and enzyme operational stability. Commercial isoamyl alcohol and fusel oil results were found to be similar as regards yield (91% vs. 84%), initial reaction rate (5.4 µM min−1 with both substrates), operational stability (40% activity loss after five runs with both) and productivity (31.09 vs. 28.7 mM h−1). EO-proROL specificity for the structural isomers of isoamyl alcohol was also evaluated. Thus, a successful biocatalyst and product conditions ready to be used for isoamyl ester industrial production are here proposed.

Synthesis of lipase-hydrogel microspheres and their application in deacidification of high-acid rice bran oil

The main challenge of rice bran oil (RBO) as a highly nutritional edible oil is the high content of free fatty acids.

Protein scaffolds: A tool for multi-enzyme assembly

The synthesis of complex molecules using multiple enzymes simultaneously in one reaction vessel has rapidly emerged as a new frontier in the field of bioprocess technology. However, operating different enzymes together in a single vessel limits their operational performance which needs to be addressed. With this respect, scaffolding proteins play an immense role in bringing different enzymes together in a specific manner. The scaffolding improves the catalytic performance, enzyme stability and provides an optimal micro-environment for biochemical reactions. This review describes the components of protein scaffolds, different ways of constructing a protein scaffold-based multi-enzyme complex, and their effects on enzyme kinetics. Moreover, different conjugation strategies viz; dockerin-cohesin interaction, SpyTag-SpyCatcher system, peptide linker-based ligation, affibody, and sortase-mediated ligation are discussed in detail. Various analytical and characterization tools that have enabled the development of these scaffolding strategies are also reviewed. Such mega-enzyme complexes promise wider applications in the field of biotechnology and bioengineering.

Current Status and Future Perspectives of Supports and Protocols for Enzyme Immobilization

The market for industrial enzymes has witnessed constant growth, which is currently around 7% a year, projected to reach $10.5 billion in 2024. Lipases are hydrolase enzymes naturally responsible for triglyceride hydrolysis. They are the most expansively used industrial biocatalysts, with wide application in a broad range of industries. However, these biocatalytic processes are usually limited by the low stability of the enzyme, the half-life time, and the processes required to solve these problems are complex and lack application feasibility at the industrial scale. Emerging technologies create new materials for enzyme carriers and sophisticate the well-known immobilization principles to produce more robust, eco-friendlier, and cheaper biocatalysts. Therefore, this review discusses the trending studies and industrial applications of the materials and protocols for lipase immobilization, analyzing their advantages and disadvantages. Finally, it summarizes the current challenges and potential alternatives for lipases at the industrial level.

Constitutive Expression in Komagataella phaffii of Mature Rhizopus oryzae Lipase Jointly with Its Truncated Prosequence Improves Production and the Biocatalyst Operational Stability

Rhizopus oryzae lipase (ROL) containing 28 C-terminal amino acids of the prosequence fused to the N-terminal mature sequence in ROL (proROL) was successfully expressed in the methylotrophic yeast Komagataella phaffii (Pichia pastoris) under the constitutive glyceraldehyde-3-phosphate dehydrogenase promoter (PGAP). Although the sequence encoding the mature lipase (rROL) was also transformed, no clones were obtained after three transformation cycles, which highlights the importance of the truncated prosequence to obtain viable transformed clones. Batch cultures of the K. phaffii strain constitutively expressing proROL scarcely influenced growth rate and exhibited a final activity and volumetric productivity more than six times higher than those obtained with proROL from K. phaffii under the methanol-inducible alcohol oxidase 1 promoter (PAOX1). The previous differences were less marked in fed-batch cultures. N-terminal analysis confirmed the presence of the 28 amino acids in proROL. In addition, immobilized proROL exhibited increased tolerance of organic solvents and an operational stability 0.25 and 3 times higher than that of immobilized rROL in biodiesel and ethyl butyrate production, respectively. Therefore, the truncated prosequence enables constitutive proROL production, boosts bioprocess performance and provides a more stable biocatalyst in two reactions in which lipases are mostly used at industrial level, esterification (ethyl butyrate) and transesterification (biodiesel).

Magnetic Nanoparticle-Containing Supports as Carriers of Immobilized Enzymes: Key Factors Influencing the Biocatalyst Performance

In this short review (Perspective), we identify key features of the performance of biocatalysts developed by the immobilization of enzymes on the supports containing magnetic nanoparticles (NPs), analyzing the scientific literature for the last five years. A clear advantage of magnetic supports is their easy separation due to the magnetic attraction between magnetic NPs and an external magnetic field, facilitating the biocatalyst reuse. This allows for savings of materials and energy in the biocatalytic process. Commonly, magnetic NPs are isolated from enzymes either by polymers, silica, or some other protective layer. However, in those cases when iron oxide NPs are in close proximity to the enzyme, the biocatalyst may display a fascinating behavior, allowing for synergy of the performance due to the enzyme-like properties shown in iron oxides. Another important parameter which is discussed in this review is the magnetic support porosity, especially in hierarchical porous supports. In the case of comparatively large pores, which can freely accommodate enzyme molecules without jeopardizing their conformation, the enzyme surface ordering may create an optimal crowding on the support, enhancing the biocatalytic performance. Other factors such as surface-modifying agents or special enzyme reactor designs can be also influential in the performance of magnetic NP based immobilized enzymes.

Immobilization of lipase on β-cyclodextrin grafted and aminopropyl-functionalized chitosan/Fe3O4 magnetic nanocomposites: An innovative approach to fruity flavor esters esterification

The lipase from Bacillus licheniformis NCU CS-5 was immobilized onto β-cyclodextrin (CD) grafted and aminopropyl-functionalized chitosan-coated Fe₃O₄ magnetic nanocomposites (Fe₃O₄-CTS-APTES-GA-β-CD). Fourier transform infrared spectroscopy, thermogravimetry analysis, X-ray diffraction, scanning electron microscopy and transmission electron microscopy showed that not only the functionalized magnetic nanoparticles were synthesized but also the immobilized lipase was successfully produced. The immobilized lipase exhibited higher optimal pH value (10.5) and temperature (60℃) than the free lipase. The pH and thermal stabilities of the immobilized lipase were improved significantly compared to the free lipase. The immobilized lipase remained more than 80% of the relative activity at temperature of 60 ℃ and pH 12.0. The immobilized lipase also remained over 80% of its relative activity after 28 days of storage and 15 cycles of application. The application of the immobilized lipase in esterification of isoamyl acetate and pentyl valerate showed that maximum esterification efficiency was achieved in n-hexane having 68.0% and 89.2% respectively. Therefore, these results indicated that the Fe₃O₄-CTS-APTES-GA-β-CD nanoparticles are novel carriers for immobilizing enzyme, and the immobilized lipase can be used as an innovative green approach to the synthesis of fruity flavor esters in food industry.

Optimization of immobilization of Pseudomonas cepacia lipase on multiwalled carbon nanotubes functionalized with glycyrrhizin and Tween 80

In the present study, multiwalled carbon nanotubes (MWCNTs) were functionalized with glycyrrhizin and Tween 80 and applied for immobilization of Pseudomonas cepacia lipase (PcL). Characterization of f-MWCNTs was performed through Fourier-transform infrared spectroscopy, thermal gravimetric, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis. The optimum specific activity of immobilized PcL (studied by Plackett-Burman statistical design) occurred at 0.3 mg/mL of f-MWCNTs, 25 mM of phosphate buffer (pH 6.0), 15 min sonication time, 8 U/mL of enzyme concentration, and 24 h immobilization time at 4 °C in the absence of glutaraldehyde. In these conditions, the specific activity was 16.57 ± 0.71 U/mg, which was very close to the predicted amount (16.62 ± 0.64 U/mg). The results of thermal and pH stability showed that the stability of immobilized PcL was higher than that of the free PcL. The activity of immobilized PcL on f-MWCNTs held 93% after being incubated for 60 min at 70 °C. Moreover, the immobilized PcL on f-MWCNTs retained about 65% of its initial activity after 30 days of storage at 25 °C. In addition, about 50% of initial activity of immobilized PcL retained after 10 cycles of uses. Therefore, f-MWCNTs could be introduced as suitable support for enzymes immobilization.

Pristine and Poly(Dimethylsiloxane) Modified Multi-Walled Carbon Nanotubes as Supports for Lipase Immobilization

The presented study deals with the fabrication of highly stable and active nanobiocatalysts based on Candida antarctica lipase B (CALB) immobilization onto pristine and poly(dimethylsiloxane) modified MWCNTs. The MWCNTs/PDMS nanocomposites, containing 40 wt.% of the polymer with two molecular weights, were successfully synthesized via adsorption modification. The effect of PDMS chains length on the textural/structural properties of produced materials was studied by means of the nitrogen adsorption–desorption technique, Raman spectroscopy, and attenuated total reflectance Fourier transform infrared spectroscopy. P-MWCNTs and MWCNTs/PDMS nanocomposites were tested as supports for lipase immobilization. Successful deposition of the enzyme onto the surface of P-MWCNTs and MWCNTs/PDMS nanocomposite materials was confirmed mainly using ATR-FTIR spectroscopy. The immobilization efficiency, stability, and catalytic activity of the immobilized enzyme were studied, and the reusability of the produced biocatalytic systems was examined. The presented results demonstrate that the produced novel biocatalysts might be considered as promising materials for biocatalytic applications.

Surface Functionalization of a γ-Graphyne-like Carbon Material via Click Chemistry

Surface functionalization of carbon materials is of interest in many research fields, such as electrocatalysis, interfacial engineering, and supercapacitors. As an emerging carbon material, γ-graphyne has attracted broad attention. Herein, we report that the surface functionalization of a γ-graphyne-like carbon material (γ-G1) is achieved by immobilizing functional groups via the click chemistry. Texture analysis of aberration-corrected microscopy, X-ray photoelectron spectroscopy, and electrochemistry confirm the successful surface modification of γ-G1 through a strong covalent linkage 1,2,3-triazole. The direct linkage of functional groups on γ-G1 via the click chemistry represents a general method for preparing other functional materials by using γ-graphyne-like materials as a skeleton.

Trends in the development of innovative nanobiocatalysts and their application in biocatalytic transformations

The ever-growing demand for cost-effective and innocuous biocatalytic transformations has prompted the rational design and development of robust biocatalytic tools. Enzyme immobilization technology lies in the formation of cooperative interactions between the tailored surface of the support and the enzyme of choice, which result in the fabrication of tremendous biocatalytic tools with desirable properties, complying with the current demands even on an industrial level. Different nanoscale materials (organic, inorganic, and green) have attracted great attention as immobilization matrices for single or multi-enzymatic systems. Aiming to unveil the potentialities of nanobiocatalytic systems, we present distinct immobilization strategies and give a thorough insight into the effect of nanosupports specific properties on the biocatalysts' structure and catalytic performance. We also highlight the development of nanobiocatalysts for their incorporation in cascade enzymatic processes and various types of batch and continuous-flow reactor systems. Remarkable emphasis is given on the application of such nanobiocatalytic tools in several biocatalytic transformations including bioremediation processes, biofuel production, and synthesis of bioactive compounds and fine chemicals for the food and pharmaceutical industry.

Electrodeposited Hybrid Biocathode-Based CO2 Reduction via Microbial Electro-Catalysis to Biofuels

Microbial electrosynthesis is a new approach to converting C1 carbon (CO₂) to more complex carbon-based products. In the present study, CO₂, a potential greenhouse gas, was used as a sole carbon source and reduced to value-added chemicals (acetate, ethanol) with the help of bioelectrochemical reduction in microbial electrosynthesis systems (MES). The performance of MES was studied with varying electrode materials (carbon felt, stainless steel, and cobalt electrodeposited carbon felt). The MES performance was assessed in terms of acetic acid and ethanol production with the help of gas chromatography (GC). The electrochemical characterization of the system was analyzed with chronoamperometry and cyclic voltammetry. The study revealed that the MES operated with hybrid cobalt electrodeposited carbon felt electrode yielded the highest acetic acid (4.4 g/L) concentration followed by carbon felt/stainless steel (3.7 g/L), plain carbon felt (2.2 g/L), and stainless steel (1.87 g/L). The alcohol concentration was also observed to be highest for the hybrid electrode (carbon felt/stainless steel/cobalt oxide is 0.352 g/L) as compared to the bare electrodes (carbon felt is 0.22 g/L) tested, which was found to be in correspondence with the pH changes in the system. Electrochemical analysis revealed improved electrotrophy in the hybrid electrode, as confirmed by the increased redox current for the hybrid electrode as compared to plain electrodes. Cyclic voltammetry analysis also confirmed the role of the biocatalyst developed on the electrode in CO₂ sequestration.

Different strategies for the lipase immobilization on the chitosan based supports and their applications

Immobilized enzymes have received incredible interests in industry, pharmaceuticals, chemistry and biochemistry sectors due to their various advantages such as ease of separation, multiple reusability, non-toxicity, biocompatibility, high activity and resistant to environmental changes. This review in between various immobilized enzymes focuses on lipase as one of the most practical enzyme and chitosan as a preferred biosupport for lipase immobilization and provides a broad range of studies of recent decade. We highlight several aspects of lipase immobilization on the surface of chitosan support containing various types of lipase and immobilization techniques from physical adsorption to covalent bonding and cross-linking with their benefits and drawbacks. The recent advances and future perspectives that can improve the present problems with lipase and chitosan such as high-price of lipase and low mechanical resistance of chitosan are also discussed. According to the literature, optimization of immobilization methods, combination of these methods with other techniques, physical and chemical modifications of chitosan, co-immobilization and protein engineering can be useful as a solution to overcome the mentioned limitations.

Immobilized lipases-based nano-biocatalytic systems - A versatile platform with incredible biotechnological potential

Lipases belong to α/β hydrolases that cause hydrolytic catalysis of triacylglycerols to release monoacylglycerols, diacylglycerols, and glycerol with free fatty acids. Lipases have a common active site that contains three amino acid residues in a conserved Gly-X-Ser-X-Gly motif: a nucleophilic serine residue, an acidic aspartic or glutamic acid residue, and a basic histidine residue. Lipase plays a significant role in numerous industrial and biotechnological processes, including paper, food, oleochemical and pharmaceutical applications. However, its instability and aqueous solubility make application expensive and relatively challenging. Immobilization has been considered as a promising approach to improve enzyme stability, reusability, and survival under extreme temperature and pH environments. Innumerable supporting material in the form of natural polymers and nanostructured materials is a crucial aspect in the procedure of lipase immobilization used to afford biocompatibility, stability in physio-chemical belongings, and profuse binding positions for enzymes. This review outlines the unique structural and functional properties of a large number of polymers and nanomaterials as robust support matrices for lipase immobilization. Given these supporting materials, the applications of immobilized lipases in different industries, such as biodiesel production, polymer synthesis, additives, detergent, textile, and food industry are also discussed.

Nanobiocatalysts for Biodiesel Synthesis through Transesterification—A Review

Converting useless feedstock into biodiesel by utilizing the process of transesterification has been regarded as an alternative approach recently used to address the fuel and energy resources shortage issues. Nanobiocatalysts (NBCs), containing the biological component of lipase enzyme immobilized on nanomaterials (NMs), have also been presented as an advanced catalyst to effectively carry out the process of transesterification with appreciable yields. This study highlights the fundamentals associated with NBCs and the transesterification reaction catalyzed by NBCs for summarizing present academic literature reported in this research domain in recent years. Classification of the NBCs with respect to the nature of NMs and immobilization methods of lipase enzyme is also provided for organizing the recently documented case studies. This review is designed to act as a guideline for the researchers aiming to explore this domain of biodiesel production via NBCs as well as for the scholars looking to expand on this field.

A phenylalanine dynamic switch controls the interfacial activation of Rhizopus chinensis lipase

The catalytic mechanism of most lipases involves a step called "interfacial activation" which significantly increases lipases activity beyond the critical micellar concentration (CMC) of substrate. In the present study, Rhizopus chinensis lipase (RCL) was used as a research model to explore the mechanism of lipase interfacial activation beyond the CMC. Molecular dynamic (MD) simulations indicated the open- and closed-lid transitions and revealed that Phe113 was the critical site for RCL activation by its dynamic flipping. Such putative switch affecting interfacial activation has not been reported in lipase so far. The function of Phe113 was subsequently verified by mutation experiments. The F113W mutant increases the lipase catalytic efficiency (1.9 s^-1·μM^-1) to 280% at the optimum temperature (40 °C) and pH 8.5 with the addition of 0.12 μg protein in the 200 μL reaction system. MD simulations indicated that the fast flipping rate from the closed to the open state, the high open state proportion, and the exposure of the catalytic triad are the main reasons for the lipase activation. The mutual corroboration of simulations and site-directed mutagenesis results revealed the vital role of Phe113 in the lipase activation.

Armoring bio-catalysis via structural and functional coordination between nanostructured materials and lipases for tailored applications

Nanostructured materials represent an interesting and novel class of support matrices for the immobilization of different enzymes. Owing to the high surface area, robust mechanical stability, outstanding optical, thermal, and electrical properties, nanomaterials have been rightly perceived as desired immobilization matrices for lipases immobilization with a wide array of biotechnological applications such as dairy, food technology, fine chemical, pharmaceutical, detergent, and oleochemical industries. Lipases immobilized on nanomaterials have demonstrated superior attributes than free counterparts, such as aggrandized pH and thermal stability, robustness, long-term stability, and the possibility of reuse and recycling in several times. Here we review current and state-of-the-art literature on the use of nanomaterials as novel platforms for the immobilization of lipase enzymes. The physicochemical properties and exploitation of a large number of new nanostructured materials such as carbon nanotubes, nano-silica, graphene/graphene oxide, metal nanoparticles, magnetic nanostructures, metal-organic frameworks, and hybrid nanoflowers as a host matrix to constitute robust lipases-based nanobiocatalytic systems are discussed. Conclusive remarks, trends, and future recommendations for nanomaterial immobilized enzymes are also given.

Lipase@zeolitic imidazolate framework ZIF-90: A highly stable and recyclable biocatalyst for the synthesis of fruity banana flavour

A zeolitic imidazolate framework (ZIF-90) has been synthesized through solvothermal method. The structure was characterized by means of FT-IR spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS). The synthesized ZIF-90 was applied as a support for immobilization of porcine pancreatic lipase (PPL). The immobilized enzyme (PPL@ZIF-90) exhibited immobilization yield and efficiency of 66 ± 1.8% and 89 ± 1.4%, respectively. The pH and thermal stability of PPL was improved after immobilization and the initial activity was retained at about 57% after 20 days of storage at 4 °C for PPL@ZIF-90. Moreover, about 57% of the original activity was remained following 10 cycles of application. In Michaelis-Menten kinetic studies, K_m value for PPL@ZIF-90 was lower, while, the V_max was higher than free PPL. Moreover, optimized conditions to produce fruity banana flavour upon esterification of butyric acid were investigated. The optimum esterification yield was 73.79 ± 1.31% in the presence of 245 mg PPL@ZIF-90, alcohol/acid ratio of 2.78 and 39 h reaction time. PPL@ZIF-90 showed 39% relative esterification yield after six cycles of reuse. The results suggested that PPL@ZIF-90 can be used as a potential effective biocatalyst for synthesis of isoamyl butyrate.