Immobilization of Candida rugosa lipase on glass beads for enantioselective hydrolysis of racemic naproxen methyl ester

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.

Protein-polymer bioconjugation, immobilization, and encapsulation: a comparative review towards applicability, functionality, activity, and stability

Polymer-based biomaterials have received a lot of attention due to their biomedical, agricultural, and industrial potential. Soluble protein-polymer bioconjugates, immobilized proteins, and encapsulated proteins have been shown to tune enzymatic activity, improved pharmacokinetic ability, increased chemical and thermal stability, stimuli responsiveness, and introduced protein recovery. Controlled polymerization techniques, increased protein-polymer attachment techniques, improved polymer surface grafting techniques, controlled polymersome self-assembly, and sophisticated characterization methods have been utilized for the development of well-defined polymer-based biomaterials. In this review we aim to provide a brief account of the field, compare these methods for engineering biomaterials, provide future directions for the field, and highlight impacts of these forms of bioconjugation.

Optimization of κ-Selenocarrageenase Production by Pseudoalteromonas sp. Xi13 and Its Immobilization

The bioenzymatic production of selenium oligosaccharides addresses the problems resulting from high molecular weight and poor water solubility of κ-selenocarrageenan, and lays foundation for its application as adjuvant drugs for cancer treatment and food additive. κ-selenocarrageenase extracted from Pseudoalteromonas sp. Xi13 can degrade κ-selenocarrageenan to selenium oligosaccharides. The maximum optimized κ-selenocarrageenase activity using Response Surface Methodology (RSM) was increased by 1.4 times, reaching 8.416 U/mL. To expand applications of the κ-selenocarrageenase in industry, the preparation conditions of it in either lyophilized or immobilized form were investigated. The activity recovery rate of the lyophilized enzyme was >70%, while that of the immobilized enzyme was 62.83%. However, the immobilized κ-selenocarrageenase exhibits good stability after being reused four times, with 58.28% of residual activity. The selenium content of κ-selenocarrageenan oligosaccharides degraded by the immobilized κ-selenocarrageenase was 47.06 µg/g, 8.3% higher than that degraded by the lyophilized enzyme. The results indicate that the immobilized κ-selenocarrageenase is suitable for industrial applications and has commercial potential.

Characterization of lipase from Candida rugosa entrapped in alginate beads to enhance its thermal stability and recyclability

Development of a simple method to efficiently immobilize lipase ensuring its stability and activity in water even at high temperatures.

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.

Calix[4]arene tetracarboxylic acid-treated lipase immobilized onto metal-organic framework: Biocatalyst for ester hydrolysis and kinetic resolution

Metal organic frameworks (MOFs) are hybrid organic inorganic materials with unique properties such as well-defined pore structure, extremely high surface area, excellent chemical-thermal stability. MOFs-based constructs have been extensively engineered and used for applications, such as enzyme immobilization for bio-catalysis. To obtained a zeolitic imidazole framework-8 (ZIF-8) for enzyme immobilization, Candida rugosa lipase (CRL) was pretreated with calix [4]arene tetracarboxylic acid (Calix) and reacted with Zn and imidazole by co-precipitation method. The prepared biocomposite was characterized by SEM, EDX, FT-IR, and XRD. The prepared CRL@Calix-ZIF-8 with high encapsulation efficiency showed improved resistance to alkali and thermal conditions. The CRL@Calix-ZIF-8 with the biocatalytic activity was 2-folds higher than that of the CRL@ZIF-8 (without Calix). The free lipase lost its catalytic activity completely at 60 °C after 100 min, while the CRL@Calix-ZIF-8 and CRL@ZIF-8 retained about 84% and 73%. It was found that CRL@Calix-ZIF-8 and CRL@ZIF-8 still retained ~83 and 67% of catalytic activity after its 6th use, respectively. The kinetic resolution of the immobilized lipases was examined for enantioselective hydrolysis of racemic naproxen methyl ester. CRL@Calix-ZIF-8 showed enantioselectivity against the racemic naproxen methyl ester, with E = 183 and 131 compared to the CRL@ZIF-8.

Microbial lipase production: A deep insight into the recent advances of lipase production and purification techniques

Importance of enzymes is ever-rising particularly microbial lipases holding great industrial worth owing to their potential to catalyze a diverse array of chemical reactions in aqueous as well as nonaqueous settings. International lipase market is anticipated to cross USD 797.7 million till 2025, rising at a 6.2% compound annual growth rate from 2017 to 2025. The recent breakthrough in the field of lipase research is the generation of new and upgraded versions of lipases via molecular strategies. For example, integration of rational enzyme design and directed enzyme evolution to attain desired properties in lipases. Normally, purification of lipase with significant purity is achieved through a multistep procedure. Such multiple step approach of lipase purification entails both conventional and novel techniques. The present review attempts to provide an overview of different aspects of lipase production including fermentation techniques, factors affecting lipase production, and purification strategies, with the aim to assist researchers to pick a suitable technique for the production and purification of lipase.

Advances in Recombinant Lipases: Production, Engineering, Immobilization and Application in the Pharmaceutical Industry

Lipases are one of the most used enzymes in the pharmaceutical industry due to their efficiency in organic syntheses, mainly in the production of enantiopure drugs. From an industrial viewpoint, the selection of an efficient expression system and host for recombinant lipase production is highly important. The most used hosts are Escherichia coli and Komagataella phaffii (previously known as Pichia pastoris) and less often reported Bacillus and Aspergillus strains. The use of efficient expression systems to overproduce homologous or heterologous lipases often require the use of strong promoters and the co-expression of chaperones. Protein engineering techniques, including rational design and directed evolution, are the most reported strategies for improving lipase characteristics. Additionally, lipases can be immobilized in different supports that enable improved properties and enzyme reuse. Here, we review approaches for strain and protein engineering, immobilization and the application of lipases in the pharmaceutical industry.

Melamine-based Covalent Organic Polymers (MCOPs) as Lipase Nanocarrier for Recyclable Esters Hydrolysis and Transesterification

Present study has successfully synthesized melamine-based covalent organic polymers (MCOPs) and applied it as lipase carrier for recyclable esters hydrolysis and transesterification. The synthesized MCOPs are composed of dense nanosheet structures having a thickness of 3.5 nm. Three immobilization methods namely physical adsorption, cross-linking and carrier activation were employed to prepare the MCOPs-immobilized CRL. Cross-linked MCOPs-immobilized CRL (41.30 mg protein/g MCOPs) and carrier activated MCOPs-immobilized CRL (33.20 mg protein/g MCOPs) had higher enzyme loading as compared to physical absorb MCOPs-immobilized CRL (29.30 mg protein/g MCOPs). Nevertheless, physical absorb MCOPs-immobilized CRL demonstrated the highest esters hydrolysis (49.85 U) and transesterification (1.04 U) activities. Despite having the highest enzymatic activity, physical absorb MCOPs-immobilized CRL were not able to maintain its catalytic stability with more than 30% decreased in enzymatic activity during consecutive hydrolysis and transesterification activities. Meanwhile, cross-linked MCOPs-immobilized CRL demonstrated highest catalytic stability with highest enzymatic activities at the end of consecutive reactions. All the MCOPs-immobilized CRL can be easily recovered and reused through centrifugation with more than 85% of recovery rate.

Kinetic resolution of racemic naproxen methyl ester by magnetic and non-magnetic cross-linked lipase aggregates

In this study, the non-magnetic and the magnetic cross-linked enzyme aggregates (CLEAs) from Candida rugosa lipase were synthesized to catalyze the kinetic resolution reaction of naproxen methyl ester (NME). Magnetic iron oxide nanoparticles (MIONPs) were produced through co-precipitation method and their surfaces were modified by silanization reaction. The MIONPs were used as a platform to synthesize the magnetic CLEAs (M-CLEAs). The biocatalysts and MIONPs synthesized were characterized by FTIR spectroscopy and SEM analysis. The kinetic resolution of racemic NME was studied in aqueous buffer solution/isooctane biphasic system to compare the performance of M-CLEAs and CLEAs. The effects of reaction parameters such as temperature, pH, stirring rate on the enantiomeric excess of the substrate (ee_s%) were investigated in a batch reactor system. The activity recovery of CRL enzyme in CLEAs was higher than M-CLEAs. Compared with M-CLEAs, CLEAs biocatalysts had previously reached ee_s% values. Although both biocatalysts showed similar cavity structure from SEM analysis, the lower performance of M-CLEAs may be due to the different microenvironments of M-CLEAs from CLEAs. However, the reusability performance of M-CLEAs was higher than that of CLEAs. The optimal reaction conditions for M-CLEAs and CLEAs were found to be 37 °C, pH 7.5, and 300 rpm.

Surface-Displayed Thermostable Candida rugosa Lipase 1 for Docosahexaenoic Acid Enrichment

Yeast surface display has emerged as a viable approach for self-immobilization enzyme as whole-cell catalysts. Herein, we displayed Candida rugosa lipase 1 (CRL LIP1) on the cell wall of Pichia pastoris for docosahexaenoic acid (DHA) enrichment in algae oil. After a 96-h culture, the displayed CRL LIP1 achieved the highest activity (380 ± 2.8 U/g) for hydrolyzing olive oil under optimal pH (7.5) and temperature (45 °C) conditions. Additionally, we improved the thermal stability of displayed LIP1, enabling retention of 50% of its initial bioactivity following 6 h of incubation at 45 °C. Furthermore, the content of DHA enhanced from 40.61% in original algae oil to 50.44% in glyceride, resulting in a 1.24-fold increase in yield. The displayed CRL LIP1 exhibited an improved thermal stability and a high degree of bioactivity toward its native macromolecule substrates algae oil and olive oil, thereby expanding its potential for industrial applications in fields of food and pharmaceutical. These results suggested that surface display provides an effective strategy for simultaneous convenient expression and target protein immobilization.

Directly covalent immobilization of Candida antarctica lipase B on oxidized aspen powder by introducing poly‑lysines: An economical approach to improve enzyme performance

In our previous study, we could achieve high soluble expression of Candida antarctica lipase B (CalB) in E. coli by fusion poly‑amino acid tags on CalB (pCalB). Herein, we are surprised to find that pCalB can be easily and directly covalent binding on a simply oxidized aspen powder (OAP) by the aid of poly‑lysine tags. Under the optimal conditions, 72.9 ± 3.6% of the total protein could be immobilized, and the activity recovery of immobilized pCalB (pCalB-OAP) was 98.9 ± 3.8%. The analysis of scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) indicated that OAP was a suitable carrier for enzyme immobilization. The immobilized pCalB-OAP could exhibit excellent thermal stabilities, and it retained a residual activity of 58.4 ± 2.8% at 55 °C, whereas only 21.2 ± 2.2% of its initial activity for free pCalB was observed. And it could also display a nice tolerance for the changes of pH environment, compared with that of free pCalB. The results that pCalB-OAP could retained 73.6 ± 2.9% of their initial activity in (R, S)-NEMPAME hydrolysis after the tenth cycles, suggested that pCalB-OAP could be effectively recycled. The immobilization strategies established here were simple and inexpensive.

A robust nanobiocatalyst based on high performance lipase immobilized to novel synthesised poly(o-toluidine) functionalized magnetic nanocomposite: Sterling stability and application

Herein, as a promising support, a magnetic enzyme nanoformulation have been designed and fabricated by a poly-o-toluidine modification approach. Owing to the magnetic nature and the existence of amine functionalized groups, the as-synthesised poly(o-toluidine) functionalized magnetic nanocomposite (Fe₃O₄@POT) was employed as potential support for Candida rugosa lipase (CRL) immobilization to explore its application in fruit flavour esters synthesis. The morphology and structure of the Fe₃O₄@POT NC were examined through various analytical tools. Hydrolytic activity assays disclose that immobilized lipase demonstrated an activity yield of 120%. It is worth mentioning that CRL#Fe₃O₄@POT showed superior resistance to extremes of temperature and pH and different organic solvents in contrast to free CRL. The magnetic behaviour of the as-synthesised NC was affirmed by alternating gradient magnetometer analysis. It was found to own facile immobilization process, enhanced catalytic performance for the immobilized form which may be stretched to the immobilization of various vital industrial enzymes. Moreover, it retained improved recycling performance. After 10 cycles of repetitive uses, it still possessed around 90% of its initial activity for the hydrolytic reaction, since the enzyme-magnetic nanoconjugate was effortlessly obtained using a magnet from the reaction system. The formulated nanobiocatalyst was selected for the esterification reaction to synthesize the fruit flavour esters, ethyl acetoacetate and ethyl valerate. The immobilized lipase successfully synthesised flavour compounds in aqueous and n-hexane media having significant higher ester yields compared to free enzyme. The present work successfully combines an industrially prominent biocatalyst, CRL, and a novel magnetic nanocarrier, Fe₃O₄@POT, into an immobilized nanoformulation with upgraded catalytic properties which has excellent potential for practical industrial implications.

Immobilization and characterization of lipase from an indigenous Bacillus aryabhattai SE3-PB isolated from lipid-rich wastewater

Extracellular lipase from an indigenous Bacillus aryabhattai SE3-PB was immobilized in alginate beads by entrapment method. After optimization of immobilization conditions, maximum immobilization efficiencies of 77% ± 1.53% and 75.99% ± 3.49% were recorded at optimum concentrations of 2% (w/v) sodium alginate and 0.2 M calcium chloride, respectively, for the entrapped enzyme. Biochemical properties of both free and immobilized lipase revealed no change in the optimum temperature and pH of both enzyme preparations, with maximum activity attained at 60 °C and 9.5, respectively. In comparison to free lipase, the immobilized enzyme exhibited improved stability over the studied pH range (8.5-9.5) and temperature (55-65 °C) when incubated for 3 h. Furthermore, the immobilized lipase showed enhanced enzyme-substrate affinity and higher catalytic efficiency when compared to soluble enzyme. The entrapped enzyme was also found to be more stable, retaining 61.51% and 49.44% of its original activity after being stored for 30 days at 4 °C and 25 °C, respectively. In addition, the insolubilized enzyme exhibited good reusability with 18.46% relative activity after being repeatedly used for six times. These findings suggest the efficient and sustainable use of the developed immobilized lipase for various biotechnological applications.

Synthesis and characterization of lactose fatty acid ester biosurfactants using free and immobilized lipases in organic solvents

In this work, lactose fatty acid esters were enzymatically synthesized from fatty acids and lactose using Candida antarctica B lipase (CALB) in organic solvents. Products were purified using a solvent extraction method and analyzed using ATR-FTIR and surface-active properties measurements. Results showed that hexanes and acetonitrile provide the highest conversions for both free and immobilized lipases, up to 77% and 93% respectively. The conversion rate of esterification is solvent-dependent for free lipase; the conversion rate of immobilized lipase still shows solvent dependency, but to a lesser degree. Surface tension, interfacial tension, critical micelle concentration (CMC), and contact angles were also measured for all of the samples, showing the potentials of these sugar esters as naturally derived surfactants for the food industry.

Environmentally-friendly strategy for separation of 1,3-propanediol using biocatalytic conversion

Glycerol waste from the biodiesel production can be used as a carbon source in the production of 1,3-propanediol (1,3-PD) through microbial fermentation. However, downstream processing is a major bottleneck that restricts its biological production. Here, we investigated an environmentally-friendly method to enzymatically separate 1,3-PD. The transformation of 1,3-PD to an ester was achieved by exploiting the esterification reaction with fatty acids under lipase catalysis. The reaction efficiency was optimized using different poly-alcohols that were existed in the fermentation broth reacted with a fatty acid. Whereas the 1,3-PD conversion reached 62%, only a 0.06% and 0.08% conversion was reached for 2,3-butanediol and glycerol, illustrating the former's more efficient separation. The recovery efficiency of 1,3-PD was 96%. Finally, 1,3-PD was obtained by lipase-directed ester hydrolysis. Taken together, the bio-catalyzed separation process presented here is a novel and promising method for recovering 1,3-PD.

Lipase immobilization on facile synthesized polyaniline-coated silver-functionalized graphene oxide nanocomposites as novel biocatalysts: stability and activity insights

Schematic representation of the preparation of PANI/Ag/GO-NCs and immobilization of lipase.

The effects of macromolecular crowding and surface charge on the properties of an immobilized enzyme: activity, thermal stability, catalytic efficiency and reusability

The microenvironment around an immobilized enzyme molecule significantly influences the properties of the immobilized enzyme.

Preparation and Characterization of Immobilized Lipase from Pseudomonas Cepacia onto Magnetic Cellulose Nanocrystals

Magnetic cellulose nanocrystals (MCNCs) were prepared and used as an enzyme support for immobilization of Pseudomonas cepacialipase (PCL). PCL was successfully immobilized onto MCNCs (PCL@MCNC) by a precipitation-cross-linking method. The resulting PCL@MCNC with a nanoscale size had high enzyme loading (82.2 mg enzyme/g) and activity recovery (95.9%). Compared with free PCL, PCL@MCNC exhibited significantly enhanced stability and solvent tolerance, due to the increase of enzyme structure rigidity. The observable optimum pH and temperature for PCL@MCNC were higher than those of free PCL. PCL@MCNC manifested relatively higher enzyme-substrate affinity and catalytic efficiency. Moreover, PCL@MCNC was capable of effectively catalyzing asymmetric hydrolysis of ketoprofenethyl ester with high yield of 43.4% and product e.e. of 83.5%. Besides, immobilization allowed PCL@MCNC reuse for at least 6 consecutive cycles retaining over 66% of its initial activity. PCL@MCNC was readily recycled by magnetic forces. Remarkably, the as-prepared nanobiocatalyst PCL@MCNC is promising for biocatalysis.

Immobilization of β-glucosidase from Aspergillus niger on κ-carrageenan hybrid matrix and its application on the production of reducing sugar from macroalgae cellulosic residue

A novel concept for the synthesis of a stable polymer hybrid matrix bead was developed in this study. The beads were further applied for enzyme immobilization to produce stable and active biocatalysts with low enzyme leakage, and high immobilization efficiency, enzyme activity, and recyclability. The immobilization conditions, including PEI concentration, activation time and pH of the PEI solution were investigated and optimized. All formulated beads were characterized for its functionalized groups, composition, surface morphology and thermal stability. Compared with the free β-glucosidase, the immobilized β-glucosidase on the hybrid matrix bead was able to tolerate broader range of pH values and higher reaction temperature up to 60 °C. The immobilized β-glucosidase was then used to hydrolyse pretreated macroalgae cellulosic residue (MCR) for the production of reducing sugar and a hydrolysis yield of 73.4% was obtained. After repeated twelve runs, immobilized β-glucosidase retained about 75% of its initial activity.

An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies.

Enzymatic reactors for biodiesel synthesis: Present status and future prospects

Lipases are being extensively researched for the production of biodiesel as a "silver bullet" in order to avoid the drawbacks of the traditional alkaline transesterification. In this review, we analyzed the main factors involved in the enzymatic synthesis of biodiesel, focusing in the choice of the immobilization protocol, and the parameters involved in the choice and configuration of the reactors. An extensive discussion is presented about the advantages and disadvantages of each type of reactor and their mode of operation. The current scenario of the market for enzymatic biodiesel and some future prospects and necessary developments are also briefly presented.

An enzyme–inorganic hybrid nanoflower based immobilized enzyme reactor with enhanced enzymatic activity

Ca₃(PO₄)₂–ChT hybrid nanoflowers were synthesized by a facile approach. The nanoflowers exhibited an enhanced enzymatic activity and can be used as an immobilized enzyme reactor (IMER) for highly efficient protein digestion.

Synthesis and characterization of chitosan/TiO2 composite beads for improving stability of porcine pancreatic lipase

The purpose of the present work is improving stability properties of porcine pancreatic lipase (triacylglycerol lipase, E.C.3.1.1.3) by immobilization on chitosan/TiO2 composite beads. The immobilization parameters were initial enzyme concentration (0.5-2 mg/ml), adsorption time (5-25 min), and glutaraldehyde concentration (1-4 % v/v). The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70 °C), pH stability (4.0-9.0), and reusability (9 times) were investigated for characterization of immobilized lipase system. The optimum temperatures of free and immobilized lipase were 30 °C. The temperature profile of the immobilized lipase was spread over a large area. The optimum pH values for the free lipase and immobilized lipase were found to be 6.5 and 7.5, respectively. The thermal stability of immobilized lipase was evaluated, and it maintained 45 % activity at 70 °C. But, at this temperature, soluble lipase protected only 15 % activity. Also, the structural characterization of chitosan/TiO2 composite beads was analyzed with scanning electron microscope (SEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and attenuated total reflection Fourier transform infrared spectroscopy analysis (ATR-FTIR). The significance of this study is improving of stability properties of lipase for the industrial usage especially production of biodiesel and dairy products.