Showing papers on "Lipase published in 2016"
TL;DR: The biomimetic mineralization process can be potentially used as an effective technique for realizing the entrapment of biomacromolecules and constructing efficient catalysts for industrial biocatalysis.
Abstract: Enhancing the activity and stability of enzymes and improving their reusability are critical challenges in the field of enzyme immobilization. Here we report a facile and efficient biomimetic mineralization to embed thermophilic lipase QLM in zeolite imidazolate framework-8 (ZIF-8). Systematic characterization indicated that the entrapment of lipase molecules was successfully achieved during the crystal growth of ZIF-8 with an enzyme loading of ∼72.2 ± 1.88 mg/g lipase@ZIF-8, and the enzymes could facilitate the construction of framework building blocks. Then the composite lipase@ZIF-8 was observed to possess favorable catalytic activity and stability in the ester hydrolysis, using the hydrolysis of p-nitrophenyl caprylate as a model. Finally, the composite was successfully applied in the kinetic resolution of (R,S)-2-octanol, with favorable catalytic activity and enantioselectivity during 10 cycle reactions. Thus, the biomimetic mineralization process can be potentially used as an effective technique for...
182 citations
TL;DR: A facile and rapid method is reported in this article to prepare a novel immobilized enzyme named lipase/Zn3(PO4)2 hybrid nanoflower, which can be described as the following four steps: crystallization and coordination, in-situ precipitation, self-assembly, size growth.
166 citations
TL;DR: It was shown that the immobilized lipase had a better catalytic activity towards the interesterification reaction and the slip melting point of the final product was lower than that of the original blend, and theinteresterification led to an obvious variation in the microstructure of the product.
149 citations
TL;DR: This study reports a facile method for co-immobilizing multiple enzymes in metal coordinated hydrogel nanofibers and indicates that metal coordinated materials using nucleotides are highly useful for interfacing with biomolecules.
Abstract: Preserving enzyme activity and promoting synergistic activity via co-localization of multiple enzymes are key topics in bionanotechnology, materials science, and analytical chemistry. This study reports a facile method for co-immobilizing multiple enzymes in metal coordinated hydrogel nanofibers. Specifically, four types of protein enzymes, including glucose oxidase, Candida rugosa lipase, α-amylase, and horseradish peroxidase, were respectively encapsulated in a gel nanofiber made of Zn2+ and adenosine monophosphate (AMP) with a simple mixing step. Most enzymes achieved quantitative loading and retained full activity. At the same time, the entrapped enzymes were more stable against temperature variation (by 7.5 °C), protease attack, extreme pH (by 2-fold), and organic solvents. After storing for 15 days, the entrapped enzyme still retained 70% activity while the free enzyme nearly completely lost its activity. Compared to nanoparticles formed with AMP and lanthanide ions, the nanofiber gels allowed much higher enzyme activity. Finally, a highly sensitive and selective biosensor for glucose was prepared using the gel nanofiber to co-immobilize glucose oxidase and horseradish peroxidase for an enzyme cascade system. A detection limit of 0.3 μM glucose with excellent selectivity was achieved. This work indicates that metal coordinated materials using nucleotides are highly useful for interfacing with biomolecules.
136 citations
TL;DR: It is demonstrated that the open and active form of lipase can be achieved and tuned with an optimized activity through chemical reduction of graphene oxide, which is a major step toward designing nanomater...
Abstract: Lipases, which can be immobilized and reused for many reaction cycles, are important enzymes with many industrial applications. A key challenge in lipase immobilization for catalysis is to open the lipase lid and maintain it in an open conformation in order to expose its active site. Here we have designed “tailor-made” graphene-based nanosupports for effective lipase (QLM) immobilization through molecular engineering, which is in general a grand challenge to control biophysicochemical interactions at the nano–bio interface. It was observed that increasing hydrophobic surface increased lipase activity due to opening of the helical lid present on lipase. The molecular mechanism of lid opening revealed in molecular dynamics simulations highlights the role of hydrophobic interactions at the interface. We demonstrated that the open and active form of lipase can be achieved and tuned with an optimized activity through chemical reduction of graphene oxide. This research is a major step toward designing nanomater...
132 citations
TL;DR: Carohydrases, that is, pectinase, xylanase and feruloyl esterase, which effectively liberated bound phenolics are known to be secreted by colonic bacteria, suggesting potential antioxidant and anti-inflammatory effects by these compounds in the large intestine during colonic fermentation.
Abstract: Unextractable phenolics from plant foods and their role in health benefits have become increasingly important. Meal residues of three quinoa seeds free of fat and extractable phenolics were subjected to acid, alkaline, and enzymatic hydrolyses. The total and individual phenolic compounds released were analyzed, and 19 phenolics, predominantly phenolic acids and several flavonoids, were identified. The concentration of bound phenolics was highest in black quinoa followed by red and white, regardless of the hydrolysis method. Higher phenolic contents also showed stronger antioxidant activities and inhibition of α-glucosidase and pancreatic lipase activities. Carbohydrases, that is, pectinase, xylanase and feruloyl esterase, which effectively liberated bound phenolics are known to be secreted by colonic bacteria, suggesting potential antioxidant and anti-inflammatory effects by these compounds in the large intestine during colonic fermentation. These results can also be applied to treat foods high in bound phenolics to enhance bioaccessibility.
128 citations
TL;DR: This representation highlights those pH values that are the most relevant for testing meal digestion in the stomach by showing the variations in gastric pH as a function of meal gastric emptying instead of time.
Abstract: The development of in vitro digestion models relies on the availability of in vivo data such as digestive enzyme levels and pH values recorded in the course of meal digestion. The variations of these parameters along the GI tract are important for designing dynamic digestion models but also static models for which the choice of representative conditions of the gastric and intestinal conditions is critical. Simulating gastric digestion with a static model and a single set of parameters is particularly challenging because the variations in pH and enzyme concentration occurring in the stomach are much broader than those occurring in the small intestine. A review of the literature on this topic reveals that most models of gastric digestion use very low pH values that are not representative of the fed conditions. This is illustrated here by showing the variations in gastric pH as a function of meal gastric emptying instead of time. This representation highlights those pH values that are the most relevant for testing meal digestion in the stomach. Gastric lipolysis is still largely ignored or is performed with microbial lipases. In vivo data on gastric lipase and lipolysis have however been collected in humans and dogs during test meals. The biochemical characterization of gastric lipase has shown that this enzyme is rather unique among lipases: (i) stability and activity in the pH range 2 to 7 with an optimum at pH 4–5.4; (ii) high tensioactivity that allows resistance to bile salts and penetration into phospholipid layers covering TAG droplets; (iii) sn-3 stereospecificity for TAG hydrolysis; and (iv) resistance to pepsin. Most of these properties have been known for more than two decades and should provide a rational basis for the replacement of gastric lipase by other lipases when gastric lipase is not available.
127 citations
TL;DR: The results suggest that this novel CLEA-lipase is potentially usable in many industrial applications and potentially dependent on the concentration of GLA or EG-NHS as a mild cross-linker.
127 citations
TL;DR: Solubility plays an important role in the bioavailability of phenolic compounds, hence this study may assist in better exploitation of phenolics from winemaking by-products as functional food ingredients and/or supplements.
125 citations
TL;DR: Under optimal experimental conditions, reusability tests of the biocatalyst (TLL-PMA) after thirty successive cycles of reaction were performed and the nature of the product (isoamyl oleate) was confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR), proton ((1)H NMR) and carbon ((13)C N MR) nuclear magnetic resonance spectroscopy analyses.
122 citations
TL;DR: The three major components of enzymatic production of biodiesel and the methods used to improve enzyme reaction, as well as a review on its economic evaluation and industrial scale production are critically discussed.
Abstract: Biodiesel is a type of renewable fuel and a potential alternative for continuously consumed fossil resources. Currently, the method applied for biodiesel production is transesterification which is divided into non-catalyzed reaction, chemical-catalyzed reaction and enzymatic reaction. Enzymatic reaction is more advantageous than the other methods because of its mild reaction conditions, easy product recovery, no wastewater generation, no saponification and higher quality of products. The main component in this reaction is an enzyme called lipase which can catalyze wide variety of substrate including free fatty acids. Two other main raw materials for biodiesel synthesis are oil and acyl acceptor such as alcohol. Biodiesel catalyzed by enzyme is affected by many factors such as lipase specificity, lipase immobilization, oil composition and purity, oil to acyl acceptor molar ratio, acyl acceptors, temperature, and water content. Many methods have been tested to manipulate these factors and improve the enzymatic reaction for biodiesel production. These methods include combination of lipases, enzyme pretreatment, enzyme post treatment, methanol addition technique, use of solvent and silica gel, and reactor design. This paper will critically discuss the three major components of enzymatic production of biodiesel and the methods used to improve enzymatic reaction, as well as a review on its economic evaluation and industrial scale production.
TL;DR: Bacillus subtilis lipase (BSL2) has been successfully immobilized into a Cu-BTC based hierarchically porous metal-organic framework material for the first time and presents high enzymatic activity and perfect reusability during the esterification reaction.
Abstract: Bacillus subtilis lipase (BSL2) has been successfully immobilized into a Cu-BTC based hierarchically porous metal–organic framework material for the first time. The Cu-BTC hierarchically porous MOF material with large mesopore apertures is prepared conveniently by using a template-free strategy under mild conditions. The immobilized BSL2 presents high enzymatic activity and perfect reusability during the esterification reaction. After 10 cycles, the immobilized BSL2 still exhibits 90.7% of its initial enzymatic activity and 99.6% of its initial conversion.
TL;DR: Compared to LS, HS group has higher lipolytic and LOX activities, TBARS, TFFA, unsaturated fatty acids and TPALDVC, which could be attributed to higher lipid hydrolysis and oxidation during processing.
TL;DR: A surfactant-activated lipase-inorganic flowerlike hybrid nanomaterials with rational design based on interfacial activation and self-assembly with superior catalytic performances is promising to find widespread use in applications related to biomedicine, biosensor, and biodiesel.
Abstract: Increasing numbers of materials have been extensively used as platforms for enzyme immobilization to improve catalytic performance. However, activity of the most of the enzymes was declined after immobilization. Here, we develop a surfactant-activated lipase-inorganic flowerlike hybrid nanomaterials with rational design based on interfacial activation and self-assembly. The resulting surfactant-activated lipase-inorganic hybird nanoflower (activated hNF-lipase) exhibited 460% and 200% higher activity than native lipase and conventional lipase-inorganic hybird nanoflower (hNF-lipase). Furthermore, the activated hNF-lipase displayed good reusability due to its monodispersity and mechanical properties, and had excellent long-time stability. The superior catalytic performances were attributed to both the conformational modulation of surfactants and hierarchical structure of nanoflowers, which not only anchored lipases in an active form, but also decreased the enzyme-support negative interaction and mass-transfer limitations. This new biocatalytic system is promising to find widespread use in applications related to biomedicine, biosensor, and biodiesel.
TL;DR: The present study provides the first evidence that these food samples (T. terrestris, chickpea) are potent inhibitors of key enzymes in digestion of carbohydrates and lipids in vitro.
TL;DR: The proposed protocol permitted the reuse of the most stable enzyme after inactivation of the least stable one, and is compatible with any immobilization protocol of the first enzyme that does not involve ion exchange as only reason for enzyme immobilization.
Abstract: This paper shows the coimmobilization of β-galactosidase from Aspergillus oryzae (β-gal) and lipase B from Candida antarctica (CALB). The combi-biocatalyst was designed in a way that permits an optimal immobilization of CALB on octyl-agarose (OC) and the reuse of this enzyme after β-gal (an enzyme with lower stability and altogether not very stabilized by multipoint covalent attachment) inactivation, both of them serious problems in enzyme co-immobilization. With this aim, OC-CALB was coated with polyethylenimine (PEI) (this treatment did not affect the enzyme activity and even improved enzyme stability, mainly in organic medium). Then, β-gal was immobilized by ion exchange on the PEI coated support. We found that PEI can become weakly adsorbed on an OC support, but the adsorption of PEI to CALB was quite strong. The immobilized β-gal can be desorbed by incubation in 300 mM NaCl. Fresh β-gal could be adsorbed afterwards, and this could be repeated for several cycles, but the amount of PEI showed a small decrease that made reincubation of the OC-CALB–PEI composite in PEI preferable in order to retain the amount of polymer. CALB activity remained unaltered under all these treatments. The combi-catalyst was submitted to inactivation at 60 °C and pH 7, conditions where β-gal was rapidly inactivated while CALB maintained its activity unaltered. All β-gal activity could be removed by incubation in 300 mM NaCl, however, SDS analysis showed that part of the enzyme β-gal molecules remained immobilized on the OC-CALC–PEI composite, as the inactivated enzyme may become more strongly adsorbed on the ion exchanger. Full release of the β-gal after inactivation was achieved using 1 M NaCl and 40 °C, conditions where CALB remained fully stable. This way, the proposed protocol permitted the reuse of the most stable enzyme after inactivation of the least stable one. It is compatible with any immobilization protocol of the first enzyme that does not involve ion exchange as only reason for enzyme immobilization.
TL;DR: In this article, date seed oil was extracted from abundantly available waste of Zahidi, Basra and Khazravi date seeds were used to produce biodiesel using acid (HCl), base (KOH), immobilized enzyme (lipase), immobilised enzyme/acid (lipasing/HCl) and immobilized enzymes/base (lipases/KOH) catalyzed processes.
TL;DR: The as-prepared nanobiocatalyst PCL@MCNC is promising for biocatalysis and capable of effectively catalyzing asymmetric hydrolysis of ketoprofenethyl ester.
Abstract: 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.
TL;DR: In this article, choline chloride (Ch]Cl)-based DESs and DES mixtures containing two hydrogen bond donors were used as cosolvents to enhance the activity and stability of Candida rugosa lipase in aqueous reactions.
Abstract: DESs (deep eutectic solvents) have many potential applications as cosolvents or anhydrous reaction media for biocatalytic reactions, owing to their non-volatility, non-flammability, non-toxicity, biocompatibility, biodegradability, and low cost. In this work, choline chloride ([Ch]Cl)-based DESs and DES mixtures containing two hydrogen bond donors were used as cosolvents to enhance the activity and stability of Candida rugosa lipase in aqueous reactions. The activity of lipase in an aqueous solution of [Ch]Cl:urea:glycerol was 155% higher than that in buffer. The half-life time of lipase at 40 °C in an aqueous solution of [Ch]Cl:glycerol was enhanced by 9.2 times. The lipase showed the highest acid stability and base stability in the aqueous solutions of [Ch]Cl:glycerol:thiourea and [Ch]Cl:ethylene glycol:formamide, respectively. In general, glycerol-containing DES mixtures were very useful in enhancing the activity and stability of lipase, while formamide-containing DES mixtures could not efficiently enhance the activity and stability of lipase. To understand the effect of DES mixtures on the activity and stability of lipase in aqueous solution, four solvatochromic parameters of DES mixtures were determined. When the solvatochromic parameters of DES mixtures were correlated with the stability of lipase in aqueous solutions of DES mixtures, it was found that thermal stability and storage stability of lipase were associated with the hydrogen bond acidity of DES mixtures. Acid stability and base stability of lipase were correlated with polarity based on Reichardt’s dye and the dipolarity/polarizability of DES mixtures, respectively.
TL;DR: A novel approach of whole cell lipase-catalyzed conversion of Scenedesmus obliquus lipids was investigated for biodiesel synthesis and most of the fuel properties of biodiesel met the specifications set by international standards.
TL;DR: A polyamidoamine (PAMAM) dendrimer was grafted onto magnetic multi-walled carbon nanotubes (m-MWCNTs) to combine magnetic properties with a large surface functionalized with amino groups as mentioned in this paper.
TL;DR: The modified starch showed better hydrophobicity and thermoplasticity with corresponding structural changes depicted by FTIR, XRD and SEM, which advocate the usefulness of the modified starch in food and biopolymer sectors.
TL;DR: In this paper, different organosilane-modified Fe3O4@SiO2 core magnetic nanocomposites with immobilized lipase and explore their potential application in biodiesel field.
TL;DR: In this article, a hybrid nanoflower was synthesized using the organic component of Burkholderia cepacia lipase and inorganic component of calcium phosphate, which exhibited an activity of 849.8 U, 308% folds of the free one, with relatively good stability.
Abstract: A new hybrid nanoflower was synthesized using the organic component of Burkholderia cepacia lipase and inorganic component of calcium phosphate. Under the optimum conditions, the nanobiocatalyst exhibited an activity of 849.8 U, 308% folds of the free one, with relatively good stability, highlighting its potential for industrialization.
TL;DR: It was shown that protein loading and stability of the biocatalysts prepared with the core–shell supports were higher than the ones obtained with commercial octyl-agarose or the commercial lipase preparations.
Abstract: Different core–shell polymeric supports, exhibiting different morphologies and composition, were produced through simultaneous suspension and emulsion polymerization, using styrene (S) and divinylbenzene (DVB) as co-monomers. Supports composed of polystyrene in both the core and the shell (PS/PS) and the new poly(styrene-co-divinylbenzene) support (PS-co-DVB/PS-co-DVB) were used for the immobilization of three different lipases (from Rhizomucor miehie (RML), from Themomyces lanuginosus (TLL) and the form B from Candida antarctica, (CALB)) and of the phospholipase Lecitase Ultra (LU). The features of the new biocatalysts were evaluated and compared to the properties of commercial biocatalysts (Novozym 435 (CALB), Lipozyme RM IM and Lipozyme TL IM) and biocatalysts prepared by enzyme immobilization onto commercial octyl-agarose, a support reported as very suitable for lipase immobilization. It was shown that protein loading and stability of the biocatalysts prepared with the core–shell supports were higher than the ones obtained with commercial octyl-agarose or the commercial lipase preparations. Besides, it was shown that the biocatalysts prepared with the core–shell supports also presented higher activities than commercial biocatalysts when employing different substrates, encouraging the use of the produced core–shell supports for immobilization of lipases and the development of new applications.
TL;DR: Almond cell walls that are completely intact limit lipid digestibility, due to an encapsulation mechanism that hinders the diffusion of lipase into the intracellular environment and lipolysis products out of the cells.
Abstract: Previous studies have provided evidence that the physical encapsulation of intracellular nutrients by cell walls of plant foods (i.e. dietary fibre) plays a predominant role in influencing macronutrient bioaccessibility (release) from plant foods during human digestion. One unexplored aspect of this is the extent to which digestive enzymes can pass through the cell-wall barrier and hydrolyse the intracellular lipid in almond seeds. The purpose of the present study was to assess the role played by cell walls in influencing the bioaccessibility and digestibility of almond lipid using a range of techniques. Digestibility experiments were performed on raw and roasted almond cells as well as isolated almond oil bodies using in vitro gastric and duodenal digestion models. Residual triacylglycerols and lipolysis products were extracted after 1 h of incubation and analysed by thin layer chromatography. The lipolysis kinetics of almond cells and oil bodies were also investigated using the pH-stat technique. Finally, the potential penetration of pancreatic lipase through the cell wall matrix was investigated using confocal microscopy. Differences in the rates and extent of lipolysis were clearly seen between almond cells and oil bodies, and these differences were observed regardless of the lipase(s) used. These results also showed that almond cell walls that are completely intact limit lipid digestibility, due to an encapsulation mechanism that hinders the diffusion of lipase into the intracellular environment and lipolysis products out of the cells.
TL;DR: A Plackett–Burman Factorial Design of 16 experiments was conducted to assess the influence of nine factors on the production of lipases by filamentous fungi, finding maximum lipolytic activities with the use of 45 g/L of yeast extract and pH 7.15.
TL;DR: The H2O2 tolerance of the lipase in HM-CSL-CLEAs was enhanced, which could relieve the inhibitory effect on lipase activity, and a high conversion yield for the epoxidation of oleic acid using H 2O2 as oxidizing agent was achieved by HM- CSL- CLEAs.
Abstract: Highly stable and easily recyclable hybrid magnetic cross-linked lipase aggregates (HM-CSL-CLEAs) were prepared by coaggregation of lipase aggregates with nonfunctionalized magnetic nanoparticles and subsequent chemical cross-linking with glutaraldehyde. Analysis by SEM and CLSM indicated that the CLEAs were embedded in nanoparticle aggregates instead of covalently immobilized. The resulting HM-CSL-CLEAs exhibited higher thermostability, storage stability, and reusability than standard CLEAs. For example, HM-CSL-CLEAs maintained >60% of their initial activity after 40 min of incubation at 60 °C, whereas standard CLEAs lost most of their activities. The HM-CSL-CLEAs can be easily recovered from the reaction mixture by an external magnetic field. Moreover, the H2O2 tolerance of the lipase in HM-CSL-CLEAs was also enhanced, which could relieve the inhibitory effect on lipase activity. A high conversion yield (55%) for the epoxidation of oleic acid using H2O2 as oxidizing agent was achieved by HM-CSL-CLEAs.
TL;DR: In this paper, a Fe3O4@MOF core-shell microsphere has been successfully prepared by growing MIL-100(Fe), three dimensional (3D) metal-organic frameworks (MOFs) onto Fe 3O4 nanoparticles.
Abstract: In this article, a Fe3O4@MOF core-shell microsphere has been successfully prepared by growing MIL-100(Fe), three dimensional (3D) metal–organic frameworks (MOFs) onto Fe3O4 nanoparticles. The resultant composite microsphere exhibited both magnetic characteristics and large specific surface area, making them excellent candidates for enzyme immobilization. Candida rugosa lipase was immobilized as a model enzyme on core-shell microspheres. The results showed that the immobilized enzyme for hydrolysis of olive oil retained >65% of its initial activity at 65 °C over 6 h; and the residual activity still remained about 60% of the initial activity after the 10th catalysis run. Therefore, such MOF based core-shell magnetic composite microspheres showed promising applications as an enzyme immobilization support.
TL;DR: 3HB was capable of protecting lipase not only against thermal-mediated denaturation but also against oxidative damage by Cu2+ and H2O2; its protection was higher than that of trehalose and comparable to that of hydroxyectoine.
Abstract: Poly(3-hydroxybutyrate) (PHB) is a common carbon- and energy-storage compound simultaneously produced and degraded into its monomer 3-hydroxybutyrate (3HB) by numerous bacteria and Archae in a metabolic pathway called the PHB cycle. We investigated 3HB as a chemical chaperone capable of protecting model enzymes, namely lipase and lysozyme, from adverse effects of high temperature and oxidation. Heat-mediated denaturation of lipase in the presence or absence of 3HB was monitored by dynamic light scattering (DLS) revealing a significant protective effect of 3HB which increased as its concentration rose. Furthermore, when compared at the same molar concentration, 3HB showed a greater protective effect than the well-known chemical chaperones trehalose and hydroxyectoine. The higher protective effect of 3HB was also confirmed when employing differential scanning calorimetry (DSC) and lysozyme as a model enzyme. Furthermore, 3HB was capable of protecting lipase not only against thermal-mediated denaturation but also against oxidative damage by Cu(2+) and H2O2; its protection was higher than that of trehalose and comparable to that of hydroxyectoine. Taking into account that the PHB-producing strain Cupriavidus necator H16 reveals a 16.5-fold higher intracellular concentration than the PHB non-producing mutant C. necator PHB(-4), it might be expected that the functional PHB cycle might be responsible for maintaining a higher intracellular level of 3HB which, aside from other positive aspects of functional PHB metabolism, enhances stress resistance of bacterial strains capable of simultaneous PHB synthesis and mobilization. In addition, 3HB can be used in various applications and formulations as an efficient enzyme-stabilizing and enzyme-protecting additive.