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Carbohydrate Polymers Oct 2020Herein, this study extracted nanocrystalline cellulose (NC) and silica (SiO) from raw oil palm leaves (OPL), and employed as nanofillers in polyethersulfone (PES) to...
Herein, this study extracted nanocrystalline cellulose (NC) and silica (SiO) from raw oil palm leaves (OPL), and employed as nanofillers in polyethersulfone (PES) to produce NC-SiO-PES as support to immobilize Candida rugosa lipase (CRL) (NC-SiO-PES/CRL). XRD, TGA-DTG and FTIR-ATR data affirmed that NC and SiO were isolated from OPL with corresponding crystallinity indices of 68 % and 70 %. A 0.02 cm membrane size with 5% (w/v) of NC-SiO without PVP K30 was optimal for membrane fabrication. CRL immobilized on the Glut-AP-NC-SiO-PES membrane gave a higher conversion of pentyl valerate (PeVa) (91.3 %, p < 0.05) compared to Glut-NC-SiO-PES (73.9 %) (p < 0.05). Characterization of the NC-SiO-PES/CRL biocatalyst verified the presence of CRL. Hence, raw OPL is a proven good source of NC and SiO, as reinforcement nanofillers in PES. The overall findings envisage the promising use of NC-SiO-PES/CRL to catalyze an expedient and high yield of PeVa, alongside the suitability of NC-SiO-PES for activating other enzymes.
Topics: Arecaceae; Biocatalysis; Cellulose; Enzyme Activation; Enzyme Stability; Enzymes, Immobilized; Fungal Proteins; Lipase; Membranes, Artificial; Palm Oil; Polymers; Saccharomycetales; Silicon Dioxide; Sulfones; Valerates
PubMed: 32718641
DOI: 10.1016/j.carbpol.2020.116549 -
Scientific Reports Jul 2020Microbial detoxification has been proposed as a new alternative for removing toxins and pollutants. In this study, the biodetoxification activities of yeasts against...
Microbial detoxification has been proposed as a new alternative for removing toxins and pollutants. In this study, the biodetoxification activities of yeasts against aflatoxin B and zinc were evaluated by HPLC and voltammetric techniques. The strains with the best activity were also subjected to complementary assays, namely biocontrol capability and heavy-metal resistance. The results indicate that the detoxification capability is toxin- and strain-dependent and is not directly related to cell growth. Therefore, we can assume that there are some other mechanisms involved in the process, which must be studied in the future. Only 33 of the 213 strains studied were capable of removing over 50% of aflatoxin B, Rhodotrorula mucilaginosa being the best-performing species detected. As for zinc, there were 39 strains that eliminated over 50% of the heavy metal, with Diutina rugosa showing the best results. Complementary experiments were carried out on the strains with the best detoxification activity. Biocontrol tests against mycotoxigenic moulds showed that almost 50% of strains had an inhibitory effect on growth. Additionally, 53% of the strains grew in the presence of 100 mg/L of zinc. It has been proven that yeasts can be useful tools for biodetoxification, although further experiments must be carried out in order to ascertain the mechanisms involved.
Topics: Aflatoxin B1; Biodegradation, Environmental; Chromatography, High Pressure Liquid; Environmental Pollutants; Food Safety; Metals, Heavy; Pichia; Rhodotorula; Saccharomyces cerevisiae; Saccharomycetales; Wastewater; Yeasts; Zinc
PubMed: 32647290
DOI: 10.1038/s41598-020-68154-4 -
Bioprocess and Biosystems Engineering Nov 2020The active site of Candida rugosa lipase (CRL) is mainly hydrophilic on its external face and hydrophobic on the internal side, and calix[n]arene-based surfactants form...
The active site of Candida rugosa lipase (CRL) is mainly hydrophilic on its external face and hydrophobic on the internal side, and calix[n]arene-based surfactants form complexes with protein residues or with strong hydrogen bonds to open up the lid. Therefore, the activity of lipase persists for a long time. In this work, a series of cyclic and acyclic anionic surfactants (sodium dodecyl sulfate (SDS), p-sulfonatocalix[4]arene, and p-sulfonatocalix[8]arene) and zwitterionic surfactants (L-proline and L-proline derivative of calix[4]arene) were used to examine the relationship between the surfactants' molecular structures and their effects on the hydrolytic activity of CRL. We explored the effects of different surfactant concentrations, ring effects, and mixing times on CRL activity and several kinetic parameters. The results demonstrated that cyclic compounds were more effective than linear structures for increasing CRL activity and the highest enzyme activity was obtained by the addition of the calix[4]-L-proline derivative. This zwitterionic compound (calix[4]-L-proline derivative) maintains the active center of enzyme and conformation by enabling electrostatic interactions and hydrogen bonding with both the acidic and basic amino acid groups in the structure of the enzyme. The results indicated that, compared with the other surfactants, activating CRL with calix[4]-L-proline resulted in hyperactivation at all concentrations (a relative increase of 230%).
Topics: Anions; Biocatalysis; Calixarenes; Candida; Catalytic Domain; Detergents; Enzymes, Immobilized; Hydrogen Bonding; Hydrogen-Ion Concentration; Hydrolysis; Kinetics; Lipase; Magnetic Resonance Spectroscopy; Phenols; Proline; Saccharomycetales; Sodium Dodecyl Sulfate; Static Electricity; Stereoisomerism; Surface-Active Agents
PubMed: 32601811
DOI: 10.1007/s00449-020-02397-3 -
International Journal of Biological... Nov 2020In this study, two synthetic layered doubled hydroxides (LDH), including Mg/Al-CO-LDH (LDH1) and Zn/Al-CO-LDH (LDH2), were prepared using the co-precipitation method and...
In this study, two synthetic layered doubled hydroxides (LDH), including Mg/Al-CO-LDH (LDH1) and Zn/Al-CO-LDH (LDH2), were prepared using the co-precipitation method and modified with sodium dodecyl sulfate to be utilized as carriers for immobilization of Candida rugosa lipase via the adsorption. The activity of prepared biocatalysts was measured in the olive oil hydrolysis. The effects of lipase concentration, pH, storage stability and thermal resistance of the samples were also studied. The maximum activity was obtained at pH 6.0 for immobilized lipase on modified LDHs with monolayer surfactants, including MLDH1 (0.922 U/mg) and MLDH2 (0.744 U/mg), respectively. The remained activities for immobilized lipase on MLDH1 and MLDH2 after 24 h incubation at 60 °C were 85% and 81%, respectively. During the 25days of storage at 4 °C, immobilized lipases on MLDH1, MLDH2, and free lipase kept 87%, 86%, and 70% of their initial activities. The residual activities for immobilized lipase on MLDH1 and MLDH2 after reusing for ten cycles were 72% and 67% of their initial activities. Adsorption parameters for sorption of lipase on all supports were fitted to the Freundlich and Langmuir isotherms. Kinetic parameters obtained from the Michaelis-Menten equation on MLDH1 and MLDH2 were comparable to free enzyme.
Topics: Enzyme Stability; Enzymes, Immobilized; Hydrogen-Ion Concentration; Hydrolysis; Hydroxides; Kinetics; Lipase; Olive Oil; Saccharomycetales; Surface-Active Agents; Temperature
PubMed: 32562729
DOI: 10.1016/j.ijbiomac.2020.06.145 -
Carbohydrate Research Jul 2020N,N,N-trimethyl chitosan (TMC), quaternized hydrophilic derivative of chitosan, has been projected to have wide applications in the pharmaceutical industry owing to its...
N,N,N-trimethyl chitosan (TMC), quaternized hydrophilic derivative of chitosan, has been projected to have wide applications in the pharmaceutical industry owing to its improved solubility at physiological conditions. However, the conventional synthesis of TMC involves toxic organic agents, which complicates its use for biological applications. Moreover, these reactions result into unwanted O-methylation and scission of the parent polymer. In the present study we have addressed these limitations by employing a green approach to synthesize TMC, by using lipase as the biocatalyst and dimethyl carbonate (DMC) as the green methylating agent, in a reaction medium comprising of ternary deep eutectic solvents (TDESs). Synthesis of TMC was carried out by using two different lipases from Burkholderia cepacia and Candida rugosa. The resulting TMC was characterized by using FTIR, H NMR, DSC, XRD. Methylation was confirmed by FTIR analysis (-CH at 1666 cm) and H NMR (?? = 3.3 ppm). DSC study revealed a lower thermal stability of TMC as compared to chitosan. These results indicated the possibility of using DMC as a green methylating agent, along with TDESs as green and sustainable solvents, for lipase catalyzed reactions. TMC was successfully synthesized and exhibited a degree of quaternization of about 12.5%, 15.69%, when synthesized used lipases from Burkholderia cepacia and Candida rugosa, respectively.
Topics: Burkholderia cepacia; Carbohydrate Conformation; Chitosan; Formates; Lipase; Saccharomycetales; Solvents
PubMed: 32505997
DOI: 10.1016/j.carres.2020.108033 -
Biotechnology and Applied Biochemistry Jun 2021The present study aimed at preparing three biocatalysts via physical adsorption of lipases from Candida rugosa (CRL), Mucor javanicus, and Candida sp. on a hydrophobic...
The present study aimed at preparing three biocatalysts via physical adsorption of lipases from Candida rugosa (CRL), Mucor javanicus, and Candida sp. on a hydrophobic and mesoporous support (Diaion HP-20). These biocatalysts were later applied to the synthesis of aromatic esters of apple peel and citrus (hexyl butyrate), apple and rose (geranyl butyrate), and apricot and pineapple (propyl butyrate). Scanning electron microscopy and gel electrophoresis confirmed a selective adsorption of lipases on Diaion, thus endorsing simultaneous immobilization and purification. Gibbs free energy (∆G) evinced the spontaneity of the process (-17.9 kJ/mol ≤ ∆G ≤ -5.1 kJ/mol). Maximum immobilized protein concentration of 30 mg/g support by CRL. This biocatalyst was the most active in olive oil hydrolysis (hydrolytic activity of 126.0 ± 2.0 U/g) and in the synthesis of aromatic esters. Maximum conversion yield of 89.1% was attained after 150 Min for the synthesis of hexyl butyrate, followed by the synthesis of geranyl butyrate (87.3% after 240 Min) and propyl butyrate (80.0% after 150 Min). CRL immobilized on Diaion retained around 93% of its original activity after six consecutive cycles of 150 Min for the synthesis of hexyl butyrate.
Topics: Enzymes, Immobilized; Esters; Hydrocarbons, Aromatic; Hydrophobic and Hydrophilic Interactions; Lipase; Mucor; Particle Size; Saccharomycetales; Surface Properties
PubMed: 32438471
DOI: 10.1002/bab.1959 -
Materials Science & Engineering. C,... Jul 2020Candida rugosa lipase (CRL) was treated with surfactants and immobilized onto the novel formulated magnetic graphene anchored silica nanocomposite (FeO/SiO/Gr NC). For...
Tailoring a robust nanozyme formulation based on surfactant stabilized lipase immobilized onto newly fabricated magnetic silica anchored graphene nanocomposite: Aggrandized stability and application.
Candida rugosa lipase (CRL) was treated with surfactants and immobilized onto the novel formulated magnetic graphene anchored silica nanocomposite (FeO/SiO/Gr NC). For this purpose, the surface of lipase was initially coated with Triton-X 100 and cetyltrimethylammonium bromide surfactants, to stabilize enzyme in its open form and was then adsorbed onto aminated FeO/SiO/Gr NC. Glutaraldehyde (GA) was then utilized to cross-link the adsorbed lipase onto the NC. The fabricated NC and conjugated lipase was characterized by various techniques such as FT-IR, XRD, TGA, SEM, TEM, CLSM, CD and Fluorescence spectroscopy. The magnetic character of the as-synthesized NC was verified by AGM investigation. CD and fluorescence spectroscopic analysis demonstrated slight structural rearrangements in lipase upon conjugation. The surfactant stabilized immobilized lipase demonstrated significantly enhanced thermostability, tolerance to various metal ions and inhibitors. The immobilization yield obtained owing to lipase interfacial activation by Triton X 100 and CTAB was remarkably enhanced by 6-folds and 3-folds, respectively which were remarkably higher in comparison to free immobilized lipase. The fabricated nanobiocatalysts were employed to synthesise green apple flavour ester, ethyl valerate via esterification reaction. Triton X 100 stabilized immobilized lipase was a better performer in yielding green apple flavour ester, demonstrating about 90% ester yield as compared to 78% yield obtained by CTAB stabilized immobilized lipase preparation. The obtained outcomes suggested that enzyme structure was stabilized by the GA treatment if executed in the absence or in the presence of detergent, and that, in the company of detergent, a conformation of the lipase with the exposed active center to the medium provided an aggrandized catalytic performance.
Topics: Biocatalysis; Enzyme Stability; Enzymes, Immobilized; Equipment Reuse; Ferrosoferric Oxide; Fungal Proteins; Graphite; Kinetics; Lipase; Magnetics; Nanocomposites; Saccharomycetales; Silicon Dioxide; Surface-Active Agents
PubMed: 32409040
DOI: 10.1016/j.msec.2020.110883 -
Applied Biochemistry and Biotechnology Oct 2020Phytosterols are regarded as compounds able to reduce total and low-density lipoprotein cholesterol in the blood, and their esterified derivatives could help to improve...
Phytosterols are regarded as compounds able to reduce total and low-density lipoprotein cholesterol in the blood, and their esterified derivatives could help to improve the effectiveness of this function. In the present study, the water/sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT)/isooctane reverse micelle (RM) system was set up as a reaction medium for Candida rugosa lipase AY30 (CRL AY30) to synthesize β-sitosterol laurate (β-SLE). The product was identified by TLC, FT-IR, and HPLC-APCI-QqQ-MS/MS and quantified by HPLC. Through stepwise optimization, it was found that CRL AY30 had the highest activity in the water/AOT/isooctane RM system where 50 mM PBS with a pH of 7.5 was adopted as water core to carry CRL AY30, and the proportion of [CRL AY30] (mg/mL), [water] (mM), and [AOT] (mM) was set in 3:375:25, respectively, in isooctane. After screened with single-factor experiments, the esterification reaction conditions in the CRL AY30-water/AOT/isooctane RM system were further optimized by the response surface method as follows: the mole ratio of β-sitosterol to lauric acid of 1:3.5 (25 mM β-sitosterol), the enzyme load of 18% (w/w total reactants), the reaction temperature of 47 °C, and the reaction time of 48 h. As a result, the maximum esterification rate was up to 88.12 ± 0.79%.
Topics: Chemistry Techniques, Synthetic; Kinetics; Lipase; Octanes; Saccharomycetales; Sitosterols; Succinates; Temperature; Water
PubMed: 32388606
DOI: 10.1007/s12010-020-03302-0 -
International Journal of Biological... Jun 2020The present study aims towards the kinetic analysis of bacterial cellulose (BC) production by Gluconobacter xylinus from biodiesel-derived crude glycerol and its...
The present study aims towards the kinetic analysis of bacterial cellulose (BC) production by Gluconobacter xylinus from biodiesel-derived crude glycerol and its application as support for immobilization of lipase. Enhancement in strength of BC membrane and its magnetic functionalization were accomplished by the impregnation of iron oxide nanoparticles into the BC matrix. Fitting of experimental results to various substrate inhibition models revealed a reduction of substrate affinity (K) and reaction rate (V), and increase in substrate inhibition concentration of G. xylinus cells in presence of crude glycerol, in comparison to the pure form of glycerol. Improvement in mechanical properties of pristine BC and magnetic strength of functionalized BC membrane were confirmed by stress-strain curve and vibrating sample magnetometry analysis, respectively. This magnetic BC membrane provided suitable support for the immobilization of Candida rugosa lipase. The immobilized enzymes exhibited better activity at various temperatures, broader pH-flexibility, thermostability (retention of 48% of its activity after 180 min at 50 °C), and reusability (59% of its activity sustained after five consecutive runs). In comparison to free lipase, the immobilized lipase exhibited improved stability and activity, which could be applicable for industrial scale.
Topics: Biofuels; Cellulose; Enzyme Stability; Enzymes, Immobilized; Gluconobacter; Glycerol; Hydrogen-Ion Concentration; Lipase; Magnets; Saccharomycetales; Temperature; Water
PubMed: 32165199
DOI: 10.1016/j.ijbiomac.2020.03.047 -
Applied Biochemistry and Biotechnology Aug 2020In this study, a new biocatalyst was prepared by immobilizing Candida rugosa lipase epichlorohydrin-functionalized onto the surface of the nanoparticles. Magnetite...
Covalent Immobilization of Candida rugosa Lipase on Epichlorohydrin-Coated Magnetite Nanoparticles: Enantioselective Hydrolysis Studies of Some Racemic Esters and HPLC Analysis.
In this study, a new biocatalyst was prepared by immobilizing Candida rugosa lipase epichlorohydrin-functionalized onto the surface of the nanoparticles. Magnetite nanoparticles were obtained by chemical co-precipitation method of Fe and Fe, and then the prepared uncoated and coated nanoparticles were characterized by XRD, FT-IR and TGA. Lipase was covalently attached to activated nanoparticles. The catalytic properties of free and immobilized lipases were determined. It was found that the optimum temperature for free and immobilized lipases was 30 °C and 35 °C, respectively. The optimum pH values were found to be 7.0 and 8 for free and immobilized lipases, respectively. Immobilized lipase was found to retain significant activity even after the seventh use. In the final section of the study, optically pure compounds were obtained by carrying out the enantioselective hydrolysis studies of racemic esters by using immobilized lipase. Enantiomeric excesses of the products in the enantioselective hydrolysis of racemic ibuprofen and naproxen methyl ester and racemic butyl mandelate were determined to be 94.93, 77.30 and 68.15, respectively.
Topics: Enzymes, Immobilized; Epichlorohydrin; Esters; Hydrogen-Ion Concentration; Hydrolysis; Industrial Microbiology; Lipase; Magnetite Nanoparticles; Saccharomycetales; Stereoisomerism; Temperature; X-Ray Diffraction
PubMed: 32103473
DOI: 10.1007/s12010-020-03274-1