High Initial Activity but Low Storage Stability Observed for Several Preparations of Subtilisin Carslberg Suspended in Organic Solvents

2002 ◽  
Vol 18 (6) ◽  
pp. 1462-1466 ◽  
Author(s):  
S.G. Martinez ◽  
E. Alvira ◽  
L.V. Cordero ◽  
A. Ferrer ◽  
I. Montanes-Clemente ◽  
...  
Keyword(s):  
Organic Solvents ◽  
Storage Stability ◽  
Initial Activity

scholarly journals Effects of Organic Solvent on Curing Behavior and Storage Stability for Waterborne Paint Containing Catalyst Encapsulated in Micelles

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 722
Author(s):  
Shuji Yomo
Keyword(s):  
Organic Solvent ◽  
Organic Solvents ◽  
Storage Stability ◽  
Dibutyltin Dilaurate ◽  
Film Properties ◽  
Surfactant Micelles ◽  
Catalytic Function ◽  
Hydrophilic Lipophilic Balance ◽  
Before And After ◽  
And Storage

In this study, a 2-pack isocyanate curing waterborne paint (without organic solvents) encapsulating dibutyltin dilaurate (hereinafter, DBTL) in nonionic surfactant micelles with an hydrophilic–lipophilic balance of 13–14 in advance releases DBTL when the micelles are collapsed at 80 °C or higher, whereby the curing progresses rapidly. On the other hand, the viscosity levels of the paint before and after being left at 40 °C for 1 h are almost the same. Organic solvents are mandatory for waterborne paints to provide paint and film properties, but they might collapse the micelles when they are formulated in the paint. In this study, we investigate whether the abovementioned paint containing organic solvents can develop switching functionality in terms of maintaining the storage stability at 40 °C and expressing a catalytic function at 80 °C to progress the curing. As a result, we find that if the solubility of the organic solvent in water at 20 °C is at least 10 g/100 mL and the boiling point is ≤200 °C, both curing and storage stability can be achieved.

scholarly journals Storage stability of adsorbed organic solvents on charcoal tubes.

Sangyo Igaku ◽  
1985 ◽  
Vol 27 (2) ◽  
pp. 114-115
Author(s):  
Toshifumi ASHIDA ◽  
Shinya KOIKE ◽  
Kaoru OHMORI
Keyword(s):  
Organic Solvents ◽  
Storage Stability

scholarly journals Decitabine bioproduction using a biocatalyst with improved stability by adding nanocomposites

AMB Express ◽  
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mariana B. Méndez ◽  
Jorge A. Trelles ◽  
Cintia W. Rivero
Keyword(s):  
Storage Stability ◽  
Scale Up ◽  
Significant Loss ◽  
Initial Activity ◽  
Reaction Conditions ◽  
Gel Entrapment ◽  
Solvent Stability ◽  
Improved Stability ◽  
The Stability ◽  
Antitumoral Agent

Abstract A novel IDA-LaNDT derivative was able to reach the highest productivity in the biosynthesis of a well-known antitumoral agent called decitabine. However, the combination of two simple and inexpensive techniques such as ionic absorption and gel entrapment with the incorporation of a bionanocomposite such as bentonite significantly improved the stability of this biocatalyst. These modifications allowed the enhancement of storage stability (for at least 18 months), reusability (400 h of successive batches without significant loss of its initial activity), and thermal and solvent stability with respect to the non-entrapped derivative. Moreover, reaction conditions were optimized by increasing the solubility of 5-aza by dilution with dimethylsulfoxide. Therefore, a scale-up of the bioprocess was assayed using the developed biocatalyst, obtaining 221 mg/L·h of DAC. Finally, green parameters were calculated using the nanostabilized biocatalyst, whose results indicated that it was able to biosynthesize DAC by a smooth, cheap, and environmentally friendly methodology.

scholarly journals Activity and stability of immobilized Candida rugosa lipase on chitosan coated Fe3O4 nanoparticles in aqueous and organic media

2014 ◽  
Vol 10 (3) ◽  
pp. 2478-2483 ◽  
Author(s):  
Mohamed A. Abd-Elhakeem ◽  
Ahmed M. Elsayed ◽  
Taher A. Alkhulaqi
Keyword(s):  
Storage Stability ◽  
Immobilized Enzyme ◽  
Candida Rugosa ◽  
Chitosan Nanoparticles ◽  
Candida Rugosa Lipase ◽  
Initial Activity ◽  
Lipase Immobilization ◽  
Lipase Enzyme ◽  
Immobilized Candida Rugosa Lipase ◽  
And Storage

Fe3O4 (magnetite) nanoparticles were prepared by coprecipitation method, coated by chitosan and functionalized by glutaraldehyde. Lipase enzyme from Candida rugosa was immobilized on the prepared particles via cross linking reaction. Synthesis steps and characterization were examined by XRD, TEM, and FTIR.  The immobilization conditions were 10 mL of phosphate buffer (0.1 M, pH 6.5) containing 30 mg of  functionalized magnetic chitosan nanoparticles and 2.0 mg·mL-1 of lipase, immobilization temperature of 4 ℃ and immobilization time of 1 h. Under these conditions, lipase was successfully immobilized with loading capacity of 87 mg/g. The immobilized enzyme showed good operational and storage stability, where it remained stable after 30 days of storage at 4◦C.and retained about 61% of its initial activity after twenty repeated uses. Finally enzymatic catalyze synthesis of butyl and hexyl oleate at 40 ◦C with shaking (200 rpm) was realized in n-hexane and confirmed by GC analysis.

scholarly journals Horseradish Peroxidase-Carrying Electrospun Nonwoven Fabrics for the Treatment of o-Methoxyphenol

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Chao Pan ◽  
Ran Ding ◽  
Li Dong ◽  
Jing Wang ◽  
Yucai Hu
Keyword(s):  
Horseradish Peroxidase ◽  
Storage Stability ◽  
Storage Period ◽  
Industrial Applications ◽  
Initial Activity ◽  
Nonwoven Fabrics ◽  
Base Stability ◽  
Phenolic Wastewater ◽  
20 Nm ◽  
And Storage

The carboxyl-functionalized polystyrene (poly(styrene-co-methacrylic acid), PSMAA) nanofibers with average diameters of 250 ± 20 nm was prepared by electrospinning. PSMAA nanofibrous membrane were employed for immobilization of horseradish peroxidase (HRP) enzyme on the fibrous surface by a chemical method. The parameters about immobilizing HRP on the PSMAA nanofibers were studied and the influence on the activity of the HRP is discussed. This study showed that soap-free emulsion method is an ideal technology to modify the polystyrene surface and ultimately achieve enzyme immobilization on electrospun PSMAA nanofibers surfaces. Compared with free HRP, the acid-base stability, thermal stability, and storage stability of HRP were increased after the immobilization. The immobilized HRP maintained about 60% of its initial activity during a 20-day storage period. However, the free HRP maintained only 40% of its initial activity. The removal percentages of o-methoxyphenol (OMP) reached 80.2% after 120 min for immobilized HRP. These results suggest that the proposed scheme for immobilization of HRP has potential in industrial applications for the treatment of phenolic wastewater.

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 Decitabine bioproduction using a biocatalyst with improved stability by adding nanocomposites

2020 ◽  
Author(s):  
Mariana B. Méndez ◽  
Jorge A. Trelles ◽  
Cintia W Rivero
Keyword(s):  
Storage Stability ◽  
Scale Up ◽  
Significant Loss ◽  
Initial Activity ◽  
Reaction Conditions ◽  
Gel Entrapment ◽  
Solvent Stability ◽  
Improved Stability ◽  
The Stability ◽  
Antitumoral Agent

Abstract A novel IDA-LaNDT derivative was able to reach the highest productivity in the biosynthesis of a well-known antitumoral agent called decitabine. However, the combination of two simple and inexpensive techniques such as ionic absorption and gel entrapment with the incorporation of a bionanocomposite such as bentonite significantly improved the stability of this biocatalyst. These modifications allowed the enhancement of storage stability (for at least 18 months), reusability (400 h of successive batches without significant loss of its initial activity), and thermal and solvent stability with respect to the non-entrapped derivative. Moreover, reaction conditions were optimized by increasing the solubility of 5-aza by dilution with dimethylsulfoxide. Therefore, a scale-up of the bioprocess was assayed using the developed biocatalyst, obtaining 221 mg/L.h of DAC. Finally, green parameters were calculated using the nanostabilized biocatalyst, whose results indicated that it was able to biosynthesize DAC by a smooth, cheap, and environmentally friendly methodology.

Laccase Incorporated into PEG-PLA Polymer as Active and Stable Biocatalyst for Ionic Liquids Media

2014 ◽  
Vol 625 ◽  
pp. 333-336 ◽  
Author(s):  
Muhammad Moniruzzaman ◽  
Yoichiro Nao ◽  
Sekhar Bhattacharjee ◽  
Tsutomu Ono
Keyword(s):  
Electron Microscopy ◽  
Storage Stability ◽  
Biological Functions ◽  
Initial Activity ◽  
Poly Ethylene Glycol ◽  
Oil Emulsion ◽  
Composites Materials ◽  
Poly Ethylene ◽  
Water In Oil Emulsion ◽  
Scanning Electron

Laccase Y20 (EC.1.10.3.2) was coated with poly (ethylene glycol)-block-polylactide (PEG-PLA, MW= 27680) via water-in-oil emulsion, and the activity and stability of the resulting PEG-PLA-laccase complex have been compared to those for the native laccase and lyophilized native laccase in an ionic liquid (IL) [C2mim][PF6] (1-ethyl-3-methylimidazolium hexafluorophosphate. The formation of spherical PEG-PLA-laccase complex of 330-480 nm was demonstrated by scanning electron microscopy. This polymer-laccase complex retained most of its enzymatic catalytic activity and exhibited excellent storage stability in IL, with over 70% of its initial activity retained after 12 days of storage in IL at 40 °C, whereas it was about 20% for native laccase under the identical conditions. This strategy could be employed to fabricate polymer based composites materials with novel biological functions.

scholarly journals Immobilization of Trypsin from Porcine Pancreas onto Chitosan Nonwoven by Covalent Bonding

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1462 ◽  
Author(s):  
Kim ◽  
Lee
Keyword(s):  
Thermal Stability ◽  
Storage Stability ◽  
Treatment Time ◽  
Reaction Times ◽  
Enzyme Concentration ◽  
Sem Analysis ◽  
Initial Activity ◽  
Porcine Pancreas ◽  
Immobilized Trypsin ◽  
Aldehyde Groups

The present study deals with the potential application of chitosan nonwoven for biomedical textiles based on enzyme immobilization. For this, chitosan nonwoven was first cross-linked with glutaraldehyde to introduce aldehyde groups at optimal conditions. To immobilize the enzyme trypsin onto glutaraldehyde-pre-activated chitosan nonwoven, several parameters such as pH, enzyme concentration, and reaction times were investigated. In addition, the pH, thermal stability, storage stability, and reusability of immobilized trypsin were examined. We found that the optimal immobilization conditions for trypsin were pH 8.5, enzyme concentration of 8% (owf), and treatment time of 30 min. Trypsin was immobilized at 25 °C efficiently. The immobilized trypsin showed lower pH stability and better thermal stability than free trypsin. The immobilized trypsin showed 50% of its initial activity after being used 15 times and 80% of that after 20 days of storage at 4 °C. SEM analysis also confirmed that trypsin was immobilized on chitosan nonwoven.

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