Immobilization Of Candida Rugosa Lipase Research Articles

Functionalized Ionic Liquids-Modified Metal-Organic Framework Material Boosted the Enzymatic Performance of Lipase.

The development of immobilized enzymes with high activity and stability is critical. Metal-organic frameworks (MOFs) have attracted much academic and industrial interest in the field of enzyme immobilization due to their unique properties. In this study, the amino-functionalized ionic liquid (NIL)-modified metal-organic framework (UiO-66-NH2) was prepared to immobilize Candida rugosa lipase (CRL), using dialdehyde starch (DAS) as the cross-linker. The results of the Fourier transform infrared (FT-IR) spectra, X-ray powder diffraction (XRD), and scanning electronic microscopy (SEM) confirmed that the NIL was successfully grafted to UiO-66-NH2. The CRL immobilized on NIL-modified UiO-66-NH2 (UiO-66-NH2-NIL-DAS@CRL) exhibited satisfactory activity recovery (79.33%), stability, reusability, and excellent organic solvent tolerance. The research results indicated that ionic liquid-modified UiO-66-NH2 had practical potential for application in enzyme immobilization.

Octadecyl and sulfonyl modification of diatomite synergistically improved the immobilization efficiency of lipase and its application in the synthesis of pine sterol esters.

Phytosterols usually have to be esterified to various phytosterol esters to avoid their disadvantages of unsatisfactory solubility and low bioavailability. The enzymatic synthesis of phytosterol esters in a solvent-free system has advantages in terms of environmental friendliness, sustainability, and selectivity. However, the limitation of the low stability and recyclability of the lipase in the solvent-free system, which often requires a relatively high temperature to induce the viscosity, also increased the industrial production cost. In this context, a low-cost material, namely diatomite, was employed as the support in the immobilization of Candida rugosa lipase (CRL) due to its multiple modification sites. The Fe3 O4 was also then introduced to this system for quick and simple separation via the magnetic field. Moreover, to further enhance the immobilization efficiency of diatomite, a modification strategy which involved the octadecyl and sulfonyl group for regulating the hydrophobicity and interaction between the support and lipase was successfully developed. The optimization of the ratio of the modifiers suggested that the -SO3 H/C18 (1:1.5) performed best with an enzyme loading and enzyme activity of 84.8mg·g-1 and 54 U·g-1 , respectively. Compared with free CRL, the thermal and storage stability of CRL@OSMD was significantly improved, which lays the foundation for the catalytic synthesis of phytosterol esters in solvent-free systems. Fortunately, a yield of 95.0% was achieved after optimizing the reaction conditions, and a yield of 70.0% can still be maintained after six cycles.

Adsorption study of isotherms, kinetics modelling, and thermodynamics of immobilized Candida rugosa lipase on metal oxide for esterification of waste cooking oil

The problem regarding improper disposal of waste cooking oil (WCO) can be solved via biotransformation of WCO to value added product using lipases as a biocatalyst. Thus, immobilization method was proposed for the recyclability of the biocatalyst. However, a comprehensive discussion on adsorption study is limited for lipase immobilization. In this study, Candida rugosa lipase (CRL) was immobilized on modified metal oxide (Mg2+/Al2O3) and the support was improved by addition of activating agent (L-lysine/Mg2+/Al2O3). Subsequently, the biocatalysts were used for esterification of WCO in the presence of methanol. Maximum adsorption capacity for the support was improved after addition of L-lysine resulting in 0.262 mg protein/g of support. The equilibrium adsorption data for both systems were fitted to the Redlich Peterson isotherm model while the kinetics study was most fitted with Elovich model, and the adsorption process were influenced by intraparticle and film diffusion mechanisms. Thermodynamic analysis explained that the adsorption process of CRL/L-lysine/Mg2+/Al2O3 was more spontaneous and stronger as compared to CRL/Mg2+/Al2O3. Furthermore, CRL/L-Lysine/Mg2+/Al2O3 exhibited its potential in esterification of WCO by converting 62.95% of free fatty acid (FFA), while CRL/Mg2+/Al2O3 converted lower FFA (53.62%). This study offers a fundamental understanding on designing an effective immobilization system by addition of activating agent to develop a good biocatalyst for biotransformation of WCO.

Green synthesis of iron-alginate nanoparticle for Taguchi-assisted immobilization of Candida rugosa lipase and its application in the synthesis of butyl butyrate ester

The synthesis of butyl butyrate, medium chain flavored esters by green chemistry is of immense importance to the food industry. In the present work, green synthesis of iron-alginate nanogels is done using a water-in-oil microemulsion method using food-grade oil for immobilization of Candida rugosa lipase (CrL). The morphological characterization of Fe-Alg nanogels was accomplished using dynamic light scattering (DLS) and scanning electron microscopy (SEM). Elongated tube-shaped Fe-Alg showed a hydrodynamic diameter of 100 ± 2 nm and a zeta potential of − 28 ± 4 mV. The nanogels exhibit an immobilization efficiency of 98%. Taguchi design-assisted immobilization of CrL onto Fe-Alg was effective in predicting the maximum response against immobilization parameters (0.7 µgm/ml of substrate, 20 min immobilization, 53⁰ C and pH 8.5). The esterification of butyl butyrate (∼90%) was completed in 6 h, which is confirmed by gas chromatography. The application of food-grade oil in the microemulsion method (water-in-oil) of nanogel synthesis is an attractive improvement for the development of support matrix in enzyme immobilization and ester synthesis.

Immobilization of Candida rugosa lipase on optimized polyamidoamine dendrimer functionalized magnetic multiwalled carbon nanotubes for green manufacture of butyl butyrate ester

Mineral acid catalysis in Fisher-Speier esterification is hazardous and have other disadvantages. The objective of the study was immobilization of Candida rugosa lipase onto iron oxide (Fe3O4) impregnated magnetic mutiwalled carbon naotubes (MMWCNTs) using amine functionalized polyamidoamine (PAMAM) dendrimers for manufacture of butyl butyrate ester. Dendrimers were synthesized from reaction of ethyl methacrylate with varying chain length of diamines 1, 4 diaminobutane (DAB) / 1, 3 diaminopropane (DAP) / ethylene diamine (ED). The effect of aliphatic alkyl chain length (CH2) of functionalizing agents ED, DAP and DAB, and dendrimer generations on amount of terminal NH2 group, surface charge, protein loading and immobilized enzyme activities were analysed. Magnetic MWCNTs support surface modified with third generation PAMAM using ethylene diamine showed highest protein load 220.1 mg g−1 and enzymatic activity 8,276.21 U g−1 support. The immobilized enzyme particles were characterized by HRTEM, FTIR, XRD, TGA, VSM and Zeta potential analysis. The immobilized enzyme showed improvement in the dispersion, activity, stability and reusability characteristics. Maximum esterification yield 92.67 % and reuse upto 11 cycles with 65.2 % yield obtained. The immobilized preparation showed 2.3 folds esterification than free enzyme. Developed nanobiocatalyst expects to possess potential for various other applications of lipase catalysed reactions.

Preparation and characterization of stable biopolymer-based nanogel for studying its application in immobilization of Candida rugosa lipase

Preparation and characterization of stable biopolymer-based nanogel for studying its application in immobilization of Candida rugosa lipase

The effect of immobilization parameters towards Candida rugosa lipase immobilization on magnesium oxide-aluminium oxide via adsorption

Candida rugosa lipase (CRL) can catalyze many chemical reactions and are widely used in industrial application. Nevertheless, its shortcomings include poor recyclability and a lack of stability. These limitations can be resolved using immobilization technique. The objective of this work was to evaluate the capability of magnesium oxide-aluminium oxide (MgO-Al2O3) as a support for CRL immobilization by physical adsorption. The effect of five immobilization parameters including agitation speed, temperature, CRL loading, immobilization time and weight of MgO-Al2O3 were investigated in this study. The optimal conditions were determined to be at 100 rpm, 30 °C, 1.5 g/L of CRL loading, 3-hour immobilization time and 2 g weight of MgO-Al2O3, resulted in 83.20 % of activity recovery correspond to 45.36 % of immobilization efficiency. Thus, CRL/MgO-Al2O3 was proven have a capability to be used as a biocatalyst for industrial applications.

Rapid mechanochemical production of biocomposites by encapsulating enzymes to zinc based-two metal organic frameworks (ZIF-8 and Zn-MOF-74) for enantioselective hydrolysis reaction of racemic Naproxen methyl ester

The mechanochemical encapsulation of enzymes during the synthesis of metal–organic frameworks (MOF) have been thought to be a natural, economical, new, and environmentally friendly step in synthesizing supported enzymatic catalysts. In this study, for the first time, a mechanochemical technique was employed to immobilize Candida rugosa lipase (CRL), and two zinc-based MOF types (Zn-MOF-74 and ZIF-8) were preferred. The enzyme kinetics and immobilization parameters (pH, temperature, thermal stability and reusability) of the prepared encapsulated enzymes (Zn-MOF-74@CRL and ZIF-8@CRL) were investigated. The prepared encapsulated enzymes were characterized by FTIR, SEM and XRD. It was observed that the catalytic activity of Zn-MOF-74 @CRL was six times higher than that of ZIF-8@CRL. After five reuses, the activities of Zn-MOF-74@CRL and ZIF-8@CRL were found to be 81% and 73% retained, respectively. After being subjected to 60 °C for 120 min, ZIF-8@CRL and Zn-MOF-74@CRL maintained their activities at 65% and 73%, respectively. The enantioselective hydrolysis reaction of racemic naproxen methyl ester was chosen as the model reaction. The results showed Zn-MOF-74@CRL possessed better enantioselectivity (E = 245) than ZIF-8@CRL (E = 136). This study demonstrated that it is possible to create biocatalysts with excellent catalytic properties for the pharmaceutical industry using MOFs produced by the mechanochemical method.

Optimization of microreactor-intensified transesterification reaction of sesame cake oil (sesame waste) for biodiesel production using magnetically immobilized lipase nano-biocatalyst

Enzyme-catalyzed transesterification to produce biodiesel is a time-consuming reaction. This study aimed to use a recoverable nanomagnetic immobilized enzyme and microreactor-intensified process to design a significantly rapid transesterification reaction. Immobilization of Candida Rugosa lipase (CRL) on GO-Fe3O4@TiO2 nanocomposite was optimized using response surface methodology-box–Behnken design (RSM-BBD). Results showed the highest immobilization efficiency of 92.73% at the optimum condition of CRL concentration of 2.59 mg/mL, time of 4.96 h, and temperature of 37.61 °C. Newly synthesized GO-Fe3O4@TiO2@CRL nano-biocatalyst (NBC) was characterized using FTIR, XRD, VSM, FE-SEM, EDX and elemental mapping. Immobilized CRL showed improved stability under different parameters, including pH, thermal, and methanol medium compared to free CRL. Freshly synthesized NBC was used in a microreactor to intensify the transesterification reaction of sesame cake oil to produce biodiesel. The RSM-BBD optimization of the transesterification reaction showed a maximum conversion rate of 97.03%, achieved at the NBC amount of 4.47 wt%, residence time of 13.29 min, and Me/oil molar ratio of 4.28. The generated biodiesel has all characteristics well within the ASTM D6751, demonstrating its good quality. The results of this study showed that using a microreactor could sufficiently intensify the transesterification reaction and reduce the reaction time using GO-Fe3O4@TiO2@CRL NBC.

Study on the Synthesis of Pine Sterol Esters in Solvent-free Systems Catalyzed by Candida rugosa Lipase Immobilized on Hydrophobic Macroporous Resin.

Pine sterol ester is a kind of novel food source nutrient with great advantages in lowering blood cholesterol levels, inhibiting tumors, preventing prostate enlargement, and regulating immunity. Macroporous resins with large specific surface area, stable structures, and various functional groups (epoxy, amino, and octadecyl groups) have been selected for immobilization of Candida rugosa lipase (CRL) to improve its stability and efficiency in the synthesis of pine sterol esters. A solvent-free strategy using oleic acid (substrate) as an esterification reaction medium is an important alternative for avoiding the use of organic solvents. The immobilization conditions of CRL immobilized on several kinds of commercial macroporous resins were optimized. Fortunately, by adsorption (hydrophobic interaction), a high immobilization efficiency of CRL was obtained using macroporous resins with hydrophobic octadecyl groups with an immobilization efficiency of 86.5%, enzyme loading of 138.5 mg/g and enzyme activity of 34.7 U/g. The results showed that a 95.1% yield could be obtained with a molar ratio of oleic acid to pine sterol of 5:1, an enzyme amount of 6.0 U/g (relative to pine sterol mass) at 50°C for 48 hours. The hydrophobic macroporous resin (ECR8806M) with a large specific surface area and abundant functional groups was used to achieve efficient immobilization of CRL. CRL@ECR8806M is an efficient catalyst for the synthesis of phytosterol esters and has the potential for further large-scale applications. Therefore, this simple, green, and low-cost strategy for lipase immobilization provides new possibilities for the high-efficiency production of pine sterol esters and other food source nutrients. This article is protected by copyright. All rights reserved.

Rapid prediction method of ZIF-8 immobilized Candida rugosa lipase activity by near-infrared spectroscopy

Candida rugosa lipase (CRL, EC3.1.1.3) is one of the main enzymes synthesizing esters, and ZIF-8 was chosen as an immobilization carrier for lipase. Enzyme activity testing often requires expensive reagents as substrates, and the experiment processes are time-consuming and inconvenient. As a result, a novel approach based on near-infrared spectroscopy (NIRs) was developed for predicting CRL/ZIF-8 enzyme activity. The absorbance of the immobilized enzyme catalytic system was evaluated using UV–Vis spectroscopy to investigate the amount of CRL/ZIF-8 enzyme activity. The powdered samples' near-infrared spectra were obtained. The sample’s enzyme activity data were linked with each sample’s original NIR spectra to establish the NIR model. A partial least squares (PLS) model of immobilized enzyme activity was developed by coupling spectral preprocessing with a variable screening technique. The experiments were completed within 48 h to eliminate inaccuracies between the reduction in enzyme activity with increasing laying-aside time throughout the test and the NIRs modeling. The root-mean-square error of cross-validation (RMSECV), the correlation coefficient of validation set (R) value, and the ratio of prediction to deviation (RPD) value were employed as assessment model indicators. The near-infrared spectrum model was developed by merging the best 2nd derivative spectral preprocessing with the Competitive Adaptive Reweighted Sampling (CARS) variable screening method. This model's root-mean-square error of cross-validation (RMSECV) was 0.368 U/g, the correlation coefficient of calibration set (R_cv) value was 0.943, the root-mean-square error of prediction (RMSEP) set was 0.414 U/g, the correlation coefficient of validation set (R) value was 0.952, and the ratio of prediction to deviation (RPD) was 3.0. The model demonstrates that the fitting relationship between the predicted and the reference enzyme activity value of the NIRs is satisfactory. The findings revealed a strong relationship between NIRs and CRL/ZIF-8 enzyme activity. As a result, the established model could be implemented to quantify the enzyme activity of CRL/ZIF-8 quickly by including more variations of natural samples. The prediction method is simple, rapid, and adaptable to be the theoretical and practical basis for further studying other interdisciplinary research work in enzymology and spectroscopy.

Ion Exchange Resin and Entrapped Candida rugosa Lipase for Biodiesel Synthesis in the Recirculating Packed-Bed Reactor: A Performance Comparison of Heterogeneous Catalysts

Ion exchange resins and immobilized lipase as heterogeneous catalysts are used to synthesize biodiesel for alternative fossil fuels. The use of ion exchange resins in the solid and activated phase can ease the separation process. Furthermore, resins can be reactivated and used repeatedly, reducing the need for catalysts. On the other hand, an immobilized enzyme is biodegradable and can catalyze the transesterification process to produce biodiesel with a lower alcohol-to-oil ratio, minimizing side reactions and impurities. Therefore, the catalysts used in this study are ion exchange resins, such as Lewatit MP-64, Amberlite IRA410Cl, and Diaion PK208LH, as well as immobilized Candida rugosa lipase. By using vegetable oil as a feedstock and methanol for the transesterification, biodiesel production was carried out in a packed bed reactor. The present study aims to investigate the optimum process parameters, including the concentration of resin and enzyme, resin activation time, resin types, flowrate, and stability of resin and enzyme on the biodiesel yield. The results showed that the optimum conditions for biodiesel production with ion exchange resin were 4 g of resin, activated for 3 h, and synthesized for 3 h; Lewatit obtained a biodiesel yield of 94.06%, Amberlite obtained 90.00%, and Diaion obtained 73.88%. Additionally, the stability test of the reactivated Lewatit resin showed that it still has the capability of producing biodiesel with a yield of more than 80% after three regeneration cycles. In contrast, Candida rugosa lipase as was immobilized by entrapment in sodium alginate before being used in the biodiesel production for 12 h. The results showed that lower flowrate in enzymatic biodiesel synthesis produced a higher amount of biodiesel, of up to 71.1%. Nonetheless, immobilized lipases can be used up to three times without a significant loss in biodiesel yield.

Vacuum-assisted adsorption of Candida rugosa lipase with nanotubes for monooleoglycerol synthesis

A surplus of crude glycerol has been produced as a by-product due to the escalating production of biofuels. Utilization of crude glycerol for monoolein production which offers a different approach using the abandoned crude glycerol from the biodiesel sector is the main aim of this study. Immobilized lipase was used in this investigation to catalyse the direct esterification of oleic acid and glycerol, which resulted in monoolein. The immobilized Candida rugosa lipase onto the halloysite nanotubes (HNTs) has shown remarkably promising attainment of lipase activity and loading capacity. The immobilised lipase was optimised for crucial parameters (HNT to lipase ratio, pH, temperature, and pressure) via response surface methodology (RSM). The recommended optimum conditions obtained are pH 6, 38.6 °C, and 0.33 atm (81.92% lipase activity). To analyse influences of reaction period, temperature, mixing rate, and crude glycerol to oleic acid molar ratio on the esterification reaction was carried out using the optimized conditions of immobilization process. The optimum conditions for physically immobilised lipase were to yield 88.97% monoolein produced at 42 °C in a substrate ratio of 1:4 (oleic acid: glycerol) stirred at 200 rotations per minute (rpm) with 16 h’ incubation time. Based on the research's findings, it was confirmed that HNT has good application potential for enzyme immobilization carriers.

The effect of ethanol solvent on thermostability and esterification activity of immobilized Candida rugosa lipase on celite

Lipase is an enzyme commonly applied as a catalyst in the food industry, the synthesis of bioplastics, and the production of biodiesel. Candida rugosa lipase (CRL) is one of the widely used lipases due to its high selectivity and activity. However, high operating temperatures can denature enzymes, affecting enzyme activity due to structural changes. An enzyme can be immobilized on a supporting matrix to improve stability. Ethanol as an immobilization solvent may also increase the thermostability and esterification activity. This study examines the effect of ethanol solvent on the thermostability of immobilized Candida rugosa lipase. Immobilization was carried out on the Celite-545 matrix in buffer/ethanol solution. Different operating conditions such as enzyme concentrations, immobilization temperatures, immobilization time, and immobilization pH were observed. The immobilized enzyme activity was determined by esterification reaction using butyric acid and 1-butanol as substrates and isooctane as reaction medium. The results showed that immobilization increased the esterification activity by 76% at 37°C. Thermostability of immobilized enzyme was also enhanced by 29-51%, depending on the esterification temperature.

Wax esters from waste fish oil catalysed by immobilized Candida rugosa lipase

Herein, the evaluation of waste fish (WF) oils as feedstock for the production of wax esters through transesterification reactions was reported. In particular, the synthesis of an emollient ester in the presence of oleyl alcohol and using an immobilized lipase catalyst was proposed. Lipase from Candida rugosa (CRL) was immobilized (0.5 enzyme/support wt. ratio) on a magnetic amino-functionalized hypercross-linked resin (M-HCLR-NH2) by ion exchange, interfacial activation, and covalent anchoring, mediated by 1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimide (EDC). The experimental results demonstrated the successful immobilization of lipase on the as-produced M-HCLR-NH2 with a high immobilization yield of 90%. The immobilized CRL showed very high activity and an activity recovery of ∼ 94%. The immobilized enzyme on the magnetic resin results in more stability and less sensitivity to temperature change than the free counterpart. In addition, during emollient ester synthesis in a solvent system, the immobilized enzyme exhibited very high activity, stability, and excellent reusability, with a yield of 94% after 12 h at 45 °C at an oil:alcohol molar ratio of 1:4 and an immobilized enzyme concentration of 15 wt%./wt of oil. Esters synthesized showed excellent physicochemical properties.

Solid‐Phase Lipase‐CuNPs Biohybrids as Catalysts for One‐Pot Parallel Synthesis of 2,3,4‐Triacetyl‐D‐Gluconic Acid

AbstractSolid‐phase lipase/metal nanobiohybrids, generated by growth of copper nanoparticles on enzyme matrixes immobilized on graphene, were used as heterogeneous catalysts with dual‐activity for the regioselective production of 2,3,4‐triacetyl‐D‐gluconic acid from α‐peracetylated‐glucose in a one‐pot parallel process combining a lipase‐mediated regioselective hydrolytic monodeprotection with a metal‐catalyzed oxidation in aqueous media. A novel synthetic strategy, based on the in situ fabrication of Cu nanoparticles induced by lipase molecules specifically immobilized on a multi‐layer graphene material by interfacial adsorption fixing them in the active open conformation, has been described. Thermomyces lanuginosus lipase was firstly used to prepare the functionalized multi‐layer graphene from graphite as a biographene preparation (Biographene, BIOG), support used to successfully immobilize Candida rugosa lipase (CRL). This immobilized form BIOG‐CRL was further used to create successful active bifunctional enzyme‐metal nanoarchitectures. Two different Cu‐lipase hybrids were synthesised, where Cu species and nanoparticles size were different depending on the methodology. Regioselectivity and stability of the hybrids were evaluated successfully in the production of monosaccharide building blocks, besides the robustness of the hybrids in recyclability experiments. These findings highlight the potential of these solid‐phase nanoarchitectures as useful tools in the synthesis of complex glycoderivatives for use in food, medicine, and cosmetics.

Immobilization of lipase on spent coffee grounds by physical and covalent methods: A comparison study

Spent coffee grounds were treated to obtain suitable carriers for both physical and covalent immobilization of Candida rugosa lipase. In the first case, physical adsorption was directly performed after water/organic solvent extraction of the interferents from the support, while in the second case the delignification and the activation of the support with glutaraldehyde or KIO4 were necessary. The support materials obtained were characterized by Fourier transform attenuated total reflection IR, elemental analysis, and scanning electron microscope. Each immobilization method was investigated to obtain the best insoluble biocatalyst immobilized activity, efficiency, and recovery. Emphasis was given to the study of the water/organic solvent ratio in the immobilization mixture as it has proven to be a decisive parameter. The optimized immobilized biocatalyst obtained by adsorption mechanism showed up to 33 U g−1 of immobilized enzyme activity, and a higher pH, thermal, and storage stability than the free lipase. This solid biocatalyst also preserved 100% of its activity after four recycles in p-nitrophenyl palmitate hydrolysis in hexane medium and permitted an almost 60% conversion of milk fats in fatty acids after 18 h of reaction, maintaining this value for three reuses.

Immobilization of Candida Rugosa lipase on Ca/Kit-6 used as bifunctional biocatalysts for the transesterification of coconut oil to biodiesel

Immobilization of Candida Rugosa lipase (CRL) on Ca doped Kit-6 solid was investigated via the adsorption method. Effects of the experimental parameters, such as pH value, temperature, time, and Ca content on the adsorption of CRL on Ca/Kit-6 were studied. In the Ca doped Ca/Kit-6 materials, Ca2+ coexisted in two environments: Ca2+ in CaO nanoparticles and in Ca-O-Si in the framework of Kit-6. There existed three kind of oxygen species: (1) lattice oxygen in CaO and SiO2; (2) Oxygen in structural defects; and (3) non-stoichiometric surface oxygen in OH form. The 0.5Ca/Kit-6 showed the most CRL immobilization capacity and stability under the optimal adsorption condition, which was correlated with its greater amount of basicity resulting from its more non-stoichiometric surface oxygen and oxygen in structural defects as well as more Ca2+ incorporation in the Kit-6 framework. In the production of biodiesel via transesterification of coconut oil, the catalysts showed better catalytic performance under weak basic than acidic condition. Under the optimal reaction conditions (40 °C, pH 7.5, 200 rpm, oil to methanol ratio 1:3 with stepwise addition of methanol, and 0.1 g of CRL/0.5Ca/Kit-6), the coconut oil conversion and biodiesel yield catalyzed with CRL/0.5Ca/Kit-6 was 95 and 98%, respectively. 10wt% water in the reaction mixture promoted the coconut oil transesterification to biodiesel. The CRL/0.5Ca/Kit-6 catalyst possessed bifunctional roles of the enzymatic catalysis role from immobilized CRL and the basic catalysis role from CaO doping. The CRL adsorption modes, water influence and the reaction mechanism of coconut oil transesterification were discussed.

Amino functionalization of magnetic multiwalled carbon nanotubes with flexible hydrophobic spacer for immobilization of Candida rugosa lipase and application in biocatalytic production of fruit flavour esters ethyl butyrate and butyl butyrate

Amino functionalization of magnetic multiwalled carbon nanotubes with flexible hydrophobic spacer for immobilization of Candida rugosa lipase and application in biocatalytic production of fruit flavour esters ethyl butyrate and butyl butyrate

Biochemical and Physical Characterization of Immobilized Candida rugosa Lipase on Metal Oxide Hybrid Support

Enzyme immobilization on inorganic materials is gaining more attention with the potential characteristics of high-surface-area-to-volume ratios, increasing the efficiency of enzyme loading on the support. Metal oxide hybrid support was prepared by a wetness impregnation of five metal precursors, including CaO, CuO, MgO, NiO, and ZnO, on Al2O3 and used as a support for the immobilization of Candida rugosa lipase (CRL) by adsorption. Maximum activity recovery (70.6%) and immobilization efficiency (63.2%) were obtained after optimization of five parameters using response surface methodology (RSM) by Box–Behnken design (BBD). The biochemical properties of immobilized CRL showed high thermostability up to 70 °C and a wide range in pH stability (pH 4–10). TGA-DTA and FTIR analysis were conducted, verifying thermo-decomposition of lipase and the presence of an amide bond. FESEM-EDX showed the homogeneous distribution and high dispersion of magnesium and CRL on MgO-Al2O3, while a nitrogen adsorption–desorption study confirmed MgO-Al2O3 as a mesoporous material. CRL/MgO-Al2O3 can be reused for up to 12 cycles and it demonstrated high tolerance in solvents (ethanol, isopropanol, methanol, and tert-butanol) compared to free CRL.