scholarly journals CALB Immobilized onto Magnetic Nanoparticles for Efficient Kinetic Resolution of Racemic Secondary Alcohols: Long-Term Stability and Reusability

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 490 ◽  
Author(s):  
Xiu Xing ◽  
Jun-Qi Jia ◽  
Jing-Fan Zhang ◽  
Zi-Wen Zhou ◽  
Jun Li ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Particles ◽  
Kinetic Resolution ◽  
Enantiomeric Excess ◽  
Secondary Alcohols ◽  
Optimal Conditions ◽  
Long Term Stability ◽  
Enzymatic Kinetic Resolution ◽  
Functionalized Magnetic Nanoparticles ◽  
Co Precipitation

In this study, an immobilization strategy for magnetic cross-linking enzyme aggregates of lipase B from Candida antarctica (CALB) was developed and investigated. Magnetic particles were prepared by conventional co-precipitation. The magnetic nanoparticles were modified with 3-aminopropyltriethoxysilane (APTES) to obtain surface amino-functionalized magnetic nanoparticles (APTES–Fe3O4) as immobilization materials. Glutaraldehyde was used as a crosslinker to covalently bind CALB to APTES–Fe3O4. The optimal conditions of immobilization of lipase and resolution of racemic 1-phenylethanol were investigated. Under optimal conditions, esters could be obtained with conversion of 50%, enantiomeric excess of product (eep) > 99%, enantiomeric excess of substrate (ees) > 99%, and enantiomeric ratio (E) > 1000. The magnetic CALB CLEAs were successfully used for enzymatic kinetic resolution of fifteen secondary alcohols. Compared with Novozym 435, the magnetic CALB CLEAs exhibited a better enantioselectivity for most substrates. The conversion was still greater than 49% after the magnetic CALB CLEAs had been reused 10 times in a 48 h reaction cycle; both ees and eep were close to 99%. Furthermore, there was little decrease in catalytic activity and enantioselectivity after being stored at −20 °C for 90 days.

scholarly journals Efficient and Stable Magnetic Chitosan-Lipase B from Candida Antarctica Bioconjugates in the Enzymatic Kinetic Resolution of Racemic Heteroarylethanols

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 350 ◽  
Author(s):  
Cristina Georgiana Spelmezan ◽  
László Csaba Bencze ◽  
Gabriel Katona ◽  
Florin Dan Irimie ◽  
Csaba Paizs ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Vinyl Acetate ◽  
Kinetic Resolution ◽  
Covalent Binding ◽  
Enantiomeric Excess ◽  
Candida Antarctica ◽  
Optimal Conditions ◽  
Lipase B ◽  
Magnetic Chitosan ◽  
Enzymatic Kinetic Resolution

Lipase B from Candida antarctica immobilized by covalent binding on sebacoyl-activated chitosan-coated magnetic nanoparticles proved to be an efficient biocatalyst (49.2–50% conversion in 3–16 h and >96% enantiomeric excess) for the enzymatic kinetic resolution of some racemic heteroarylethanols through transesterification with vinyl acetate. Under optimal conditions (vinyl acetate, n-hexane, 45 °C), the biocatalyst remains active after 10 cycles.

scholarly journals Biocatalysis in continuous-flow mode: A case-study in the enzymatic kinetic resolution of secondary alcohols via acylation and deacylation reactions mediated by Novozym 435®

Biocatalysis ◽  
2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Juliana Christina Thomas ◽  
Martha Daniela Burich ◽  
Pamela Taisline Bandeira ◽  
Alfredo Ricardo Marques de Oliveira ◽  
Leandro Piovan
Keyword(s):  
Continuous Flow ◽  
Energy Use ◽  
Kinetic Resolution ◽  
Enantiomeric Excess ◽  
Flow Mode ◽  
Enzymatic Reactions ◽  
Secondary Alcohols ◽  
Batch Mode ◽  
Enzymatic Kinetic Resolution

AbstractEnzymatic kinetic resolution reactions are a well-established way to achieve optically active compounds. When enzymatic reactions are combined to continuous-flow methodologies, other benefits are added, including reproducibility, optimized energy use, minimized waste generation, among others. In this context, we herein report a case study involving lipase-mediated transesterification by acylation and deacylation reactions of secondary alcohols/esters in batch and continuous-flow modes. Acylation reactions were performed with high values of enantiomeric excess (72 up to >99%) and enantioselectivity (E > 200) for both batch and continuous-flow modes. On the other hand, for deacylation reactions using n-butanol as nucleophile, enatiomeric excess ranged between 38 to >99% and E from 6 to >200 were observed for batch mode. For deacylation reactions in continuous-flow mode, results were disappointing, as in some cases, very low or no conversion was observed. Enantiomeric excess ranged from 16 to >99% and enantioselectivity from 5 to >200 were observed. In terms of productivity, continuous-flow mode reactions were superior in both strategies (acylation: r from 1.1 up to 18.1-fold higher, deacylation: 2.8 up to 7.4- fold higher in continuous-flow than in batch mode).

scholarly journals MAGNETIC NANOPARTICLES IN BIOCATALYSIS

2021 ◽  
pp. 66-72
Author(s):  
Александрина Михайловна Сульман ◽  
Ольга Валентиновна Гребенникова ◽  
Анастасия Евгеньевна Филатова
Keyword(s):  
Magnetic Nanoparticles ◽  
Horseradish Peroxidase ◽  
Kinetic Parameters ◽  
Magnetic Particles ◽  
Ph Value ◽  
Co Precipitation ◽  
Optimal Ph

В работе изучены свойства ферментативных систем на основе иммобилизованной на магнитные частицы пероксидазы корня хрена (HRP). Магнитные наночастицы FeO были синтезированы методом соосаждения. Затем на их поверхность двумя способами была иммобилизована пероксидаза корня хрена путем ковалентной сшивки. Для этого, в первом случае, FeO последовательно обрабатывали тетраэтоксисиланом, 3-аминопропилтриэтоксисиланом, глутаровым диальдегидом и HRP. Во втором, перед иммобилизацией HRP на поверхность носителя были последовательно нанесены 3-аминопропилтриэтоксисилан, глутаровым диальдегидом и HRP. Активность синтезированных биокатализаторов оценивалась спектрофотометрически в реакции окисления 2,2'-азино-бис(3-этилбензотиазолин-6-сульфонат) аммония пероксидом водорода. В работе также были рассчитаны кинетические параметры K и V для всех типов катализаторов, в том числе для нативной HRP. Среди всех биокаталитических систем лучшие значения, по сравнению с нативным ферментом (K = 4 ммоль/л и V = 12.6∙10, ммоль/л∙с) , были получены для первого типа биокатализатора (K = 5 ммоль/л и V = 2.5∙10, ммоль/л∙с). Было также определено, что оптимальным значением рН является 7.2. The synthesis of biocatalytic systems based on horseradish peroxidase immobilized on magnetic particles was investigated. The method of co-precipitation was used to obtain magnetic nanoparticles. Two types of magnetic particles were studied: untreated and pretreated with tetraethoxysilane. The basic kinetic parameters KM and Vm were calculated for all types of biocatalysts. The optimal pH value was determined for the biocatalyst that showed the greatest activity during oxidation

scholarly journals Time-Evolution Contrast of Target MRI Using High-Stability Antibody Functionalized Magnetic Nanoparticles: An Animal Model

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
K. W. Huang ◽  
S. Y. Yang ◽  
H. E. Horng ◽  
J. J. Chieh ◽  
H. H. Chen ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Resonance ◽  
Magnetic Resonance Image ◽  
Magnetic Particles ◽  
Time Window ◽  
Particle Morphology ◽  
Functionalized Magnetic Nanoparticles ◽  
Size Stability ◽  
The Mean

In this work, high-quality antibody functionalized Fe3O4magnetic nanoparticles are synthesized. Such physical characterizations as particle morphology, particle size, stability, and relaxivity of magnetic particles are investigated. The immunoreactivity of biofunctionalized magnetic nanoparticles is examined by utilizing immunomagnetic reduction. The results show that the mean diameter of antibody functionalized magnetic nanoparticles is around 50 nm, and the relaxivity of the magnetic particles is 145 (mM·s)−1. In addition to characterizing the magnetic nanoparticles, the feasibility of using the antibody functionalized magnetic nanoparticles for the contrast medium of target magnetic resonance imaging is investigated. These antibody functionalized magnetic nanoparticles are injected into mice bearing with tumor. The tumor magnetic-resonance image becomes darker after the injection and then recovers 50 hours after the injection. The tumor magnetic-resonance image becomes the darkest at around 20 hours after the injection. Thus, the observing time window for the specific labeling of tumors with antibody functionalized magnetic nanoparticles was found to be 20 hours after injecting biofunctionalized magnetic nanoparticles into mice. The biopsy of tumor is stained after the injection to prove that the long-term darkness of tumor magnetic-resonance image is due to the specific anchoring of antibody functionalized magnetic nanoparticles at tumor.

scholarly journals Synthesis and Characterization of Janus Magnetic Nanoparticles and its Application as an Adsorbent

2013 ◽  
Vol 27 ◽  
pp. 64-68 ◽  
Author(s):  
Zayed Bin Zakir Shawon
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Particles ◽  
Chemical Engineering ◽  
Pickering Emulsion ◽  
Quick Method ◽  
Coated Nanoparticles ◽  
Janus Nanoparticles ◽  
Nanoparticles Characterization ◽  
Co Precipitation

A simple and quick method to synthesize Janus magnetic particles in the nano-sized range was conducted. Magnetic nanoparticles (MNPs) with diameters in the range of 10-15 nm were prepared by the co-precipitation of Fe2+ and Fe3+ precursors under alkaline and inert condition. The Pickering Emulsion method was used for the immobilization of magnetic nanoparticles onto the surface of paraffin wax balls via water-molten wax emulsion. Silanization of the exposed side of the immobilized magnetic particles was carried out with APTES and the waxes were subsequently dissolved to obtain free Janus nanoparticles. Characterization tests such as TGA, SEM-EDX, TEM and FTIR were performed to ascertain the partial coating of the Janus nanoparticles. Moreover, adsorption capacity of the Janus nanoparticles on Hg2+ ions was found to be intermediate between those using the uncoated and fully coated nanoparticles indicating successful synthesis of Janus nanoparticles DOI: http://dx.doi.org/10.3329/jce.v27i1.15861 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 1, June 2012: 64-68

Enzymatic Kinetic Resolution of Secondary Alcohols Using an Ionic Anhydride Generated In Situ

ChemSusChem ◽  
2016 ◽  
Vol 10 (1) ◽  
pp. 296-302 ◽  
Author(s):  
Ângelo Rocha ◽  
Raquel Teixeira ◽  
Nuno M. T. Lourenço ◽  
Carlos A. M. Afonso
Keyword(s):  
Kinetic Resolution ◽  
Secondary Alcohols ◽  
Enzymatic Kinetic Resolution

scholarly journals Immobilization and Biochemical Properties of the Enantioselective Recombinant NStcI Esterase of Aspergillus nidulans

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Carolina Peña-Montes ◽  
María Elena Mondragón-Tintor ◽  
José Augusto Castro-Rodríguez ◽  
Ismael Bustos-Jaimes ◽  
Arturo Navarro-Ocaña ◽  
...  
Keyword(s):  
Kinetic Resolution ◽  
Storage Stability ◽  
Enantiomeric Excess ◽  
Residual Activity ◽  
Biochemical Properties ◽  
Maximum Activity ◽  
Acyl Donor ◽  
Initial Activity ◽  
Enzymatic Kinetic Resolution ◽  
Repeated Use

The recombinant NStcI A. nidulans esterase was adsorbed on Accurel MP1000, where protein yield and immobilization efficiency were 42.48% and 81.94%, respectively. Storage stability test at 4°C and RT showed 100% of residual activity after 40 days at both temperatures. The biocatalyst retains more than 70% of its initial activity after 3 cycles of repeated use. Biochemical properties of this new biocatalyst were obtained. Maximum activity was achieved at pH 11 and 30°C, while the best stability was observed with the pH between 9 and 11 at 40°C. NStcI thermostability was increased after immobilization, as it retained 47.5% of its initial activity after 1 h at 60°C, while the free enzyme under the same conditions displayed no activity. NStcI preserved 70% of its initial activity in 100% hexane after 72 h. Enzymatic kinetic resolution of (R,S)-1-phenylethanol was chosen as model reaction, using vinyl acetate as acyl donor. After optimization of reaction parameters, the highest possible conversion (42%) was reached at 37°C, aw of 0.07, and 120 h of bioconversion in hexane with an enantiomeric excess of 71.7%. NStcI has selectivity for (R)-enantiomer. The obtained E value (31.3) is in the range considered useful to resolve enantiomeric mixtures.

scholarly journals The production of enantiomerically pure 1-phenylethanol by enzymatic kinetic resolution method using response surface methodology

2020 ◽  
Vol 44 (5) ◽  
pp. 1352-1365
Author(s):  
Ayşe BOZAN ◽  
Rahime SONGÜR ◽  
Ülkü MEHMETOĞLU
Keyword(s):  
Response Surface Methodology ◽  
Reaction Time ◽  
Response Surface ◽  
High Performance ◽  
Kinetic Resolution ◽  
Enantiomeric Excess ◽  
Reaction Parameters ◽  
Enantiomerically Pure ◽  
Enzymatic Kinetic Resolution ◽  
Optimum Reaction

As the enantiomers of 1-phenylethanol are valuable intermediates in several industries, the lipase catalyzed kinetic resolution of (R,S) -1-phenylethanol is a relevant research topic. In this study, the goal was to determine the optimum reaction parameters to produce enantiomerically pure 1-phenylethanol by lipase (Novozyme 435) catalyzed kinetic resolution using response surface methodology (RSM). Reactions were performed with 40–400 mM (R,S)-1-phenylethanol, 120–1200 mM vinyl acetate and 2–22 mg/ mL biocatalyst concentrations (BCL), at 20–60 °C and with a stirring rate of 50–400 rpm for 5–120 min. The samples were analyzed using high performance liquid chromatography (HPLC) with a Chiralcel OB column. Optimum reaction parameters to reach 100% enantiomeric excess for the substrate (ees) were determined as follows: substrate concentration (Cs): 240 mM, BCL: 11 mg/mL, at 42 °C with a reaction time of 75 min. Model validation was performed using these conditions and ees was calculated as 100%, which indicates the predicted model was efficient and accurate. When compared to the literature, it was observed that the reaction time decreased significantly. This is an important result considering the industrial scale perspective.

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