immobilized calb
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Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1463
Author(s):  
Honghai Wang ◽  
Wenda Yue ◽  
Shuling Zhang ◽  
Yu Zhang ◽  
Chunli Li ◽  
...  

Silica xerogels have been proposed as a potential support to immobilize enzymes. Improving xerogels’ interactions with such enzymes and their mechanical strengths is critical to their practical applications. Herein, based on the mussel-inspired chemistry, we demonstrated a simple and highly effective strategy for stabilizing enzymes embedded inside silica xerogels by a polydopamine (PDA) coating through in-situ polymerization. The modified silica xerogels were characterized by scanning and transmission electron microscopy, Fourier tranform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and pore structure analyses. When the PDA-modified silica xerogels were used to immobilize enzymes of Candida antarctica lipase B (CALB), they exhibited a high loading ability of 45.6 mg/gsupport, which was higher than that of immobilized CALB in silica xerogels (28.5 mg/gsupport). The immobilized CALB of the PDA-modified silica xerogels retained 71.4% of their initial activities after 90 days of storage, whereas the free CALB retained only 30.2%. Moreover, compared with the immobilization of enzymes in silica xerogels, the mechanical properties, thermal stability and reusability of enzymes immobilized in PDA-modified silica xerogels were also improved significantly. These advantages indicate that the new hybrid material can be used as a low-cost and effective immobilized-enzyme support.


Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 411
Author(s):  
Doris Pospiech ◽  
Renata Choińska ◽  
Daniel Flugrat ◽  
Karin Sahre ◽  
Dieter Jehnichen ◽  
...  

Application of lipases (preferentially Candida antarctica Lipase B, CALB) for melt polycondensation of aliphatic polyesters by transesterification of activated dicarboxylic acids with diols allows to displace toxic metal and metal oxide catalysts. Immobilization of the enzyme enhances the activity and the temperature range of use. The possibility to use enzyme-catalyzed polycondensation in melt is studied and compared to results of polycondensations in solution. The experiments show that CALB successfully catalyzes polycondensation of both, divinyladipate and dimethylsuccinate, respectively, with 1,4-butanediol. NMR spectroscopy, relative molar masses obtained by size exclusion chromatography, MALDI-TOF MS and wide-angle X-ray scattering are employed to compare the influence of synthesis conditions for poly(butylene adipate) (PBA) and poly(butylene succinate) (PBS). It is shown that the enzymatic activity of immobilized CALB deviates and influences the molar mass. CALB-catalyzed polycondensation of PBA in solution for 24 h at 70 °C achieves molar masses of up to Mw~60,000 g/mol, higher than reported previously and comparable to conventional PBA, while melt polycondensation resulted in a moderate decrease of molar mass to Mw~31,000. Enzymatically catalyzed melt polycondensation of PBS yields Mw~23,400 g/mol vs. Mw~40,000 g/mol with titanium(IV)n-butoxide. Melt polycondensation with enzyme catalysis allows to reduce the reaction time from days to 3-4 h.


2021 ◽  
Vol 17 ◽  
pp. 379-384
Author(s):  
Alexander Leslie ◽  
Thomas S Moody ◽  
Megan Smyth ◽  
Scott Wharry ◽  
Marcus Baumann

A continuous flow process is presented that couples a Curtius rearrangement step with a biocatalytic impurity tagging strategy to produce a series of valuable Cbz-carbamate products. Immobilized CALB was exploited as a robust hydrolase to transform residual benzyl alcohol into easily separable benzyl butyrate. The resulting telescoped flow process was effectively applied across a series of acid substrates rendering the desired carbamate structures in high yield and purity. The derivatization of these products via complementary flow-based Michael addition reactions furthermore demonstrated the creation of β-amino acid species. This strategy thus highlights the applicability of this work towards the creation of important chemical building blocks for the pharmaceutical and speciality chemical industries.


2021 ◽  
Vol 245 ◽  
pp. 01023
Author(s):  
Xinlong Liu ◽  
Peng Liu ◽  
Na An ◽  
Chen Liu

Metal–organic frameworks (MOFs) are an attractive class of hybrid materials with metal clusters and organic linkers. The unusual properties of MOFs, such as permanent nanoscale porosity, high surface area, uniformly structured cavities and the availability of in-pore functionality and outer-surface modification, are advantageous using as lipase immobilization platform. Herein, we covalent immobilized CALB onto MOFs and then evaluated the biocatalyst performance in the esterification of oleic acid with methanol for biodiesel production. Experimental data about the methanolysis process was evaluated by response surface methodology. The highest yield of 98.9 ± 0.4% was obtained under the optimized conditions: methanol/oil ratio of 3.65:1, a reaction temperature of 46.3 °C, a CALB@MOF loading of 117.77 mg and a reaction time of 11.55 h, which was closed to the predicted value (100.00%). Verification experiment confirmed the validity of the predicted model.


2020 ◽  
Vol 10 (6) ◽  
pp. 6744-6756 ◽  

Enzymes have been extensively used due to their catalytic properties, and immobilization is a promising technique to enhance their catalytic activity and stability. Lipases are enzymes naturally efficient, can be employed for the production of many different molecules, and have a wide range of industrial applications thanks to their broad selectivity. The objective of the present study was to characterize the Candida antarctica B CALB immobilized obtained using the aerogel technique regarding the morphological characteristics of the aerogel silica and its stability. For this purpose, analyzes of XRD, adsorption-desorption isotherms, TGA, SEM, and stability (storage, operational, and thermal) were performed. The supports obtained have an amorphous structure and isotherm type IV. Regarding TGA, two distinct regions were obtained and studied. Aerogels showed an increase in thermal, storage, and operational stability in relation to the free enzyme and demonstrated between 8 and 12 cycles of reuse. The contribution of this work was to present the stability advantages of the immobilized CALB enzyme through the sol-gel technique.


2018 ◽  
Vol 13 (2) ◽  
pp. 208-215 ◽  
Author(s):  
Dianyu Yu ◽  
Xu Zhang ◽  
Dezhi Zou ◽  
Tong Wang ◽  
Tianyi Liu ◽  
...  
Keyword(s):  

RSC Advances ◽  
2018 ◽  
Vol 8 (24) ◽  
pp. 13364-13369 ◽  
Author(s):  
Xia Zhang ◽  
Liting Wan ◽  
Lin Li ◽  
Zhenbo Xu ◽  
Jianyu Su ◽  
...  

Immobilized CALB (I-CALB) and I-CALB solution was treated by magnetic fields and enzymatic reactions with them were compared.


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