Immobilization of exo-D-galacturonanase by coupling to a polyacrylamide type support

1986 ◽  
Vol 51 (10) ◽  
pp. 2291-2298 ◽  
Author(s):  
Kveta Heinrichová ◽  
Mária Lehoczki ◽  
Dagmar Zliechovcová
Keyword(s):  
Immobilized Enzyme ◽  
Covalent Bonding ◽  
Water Soluble ◽  
Free Enzyme ◽  
Polymeric Substrate ◽  
Temperature Optimum ◽  
Reaction Conditions ◽  
Ph Optimum ◽  
Optimal Reaction ◽  
Thermal Stability Of

Exo-D-galacturonanase (E.C. 3.2.1.67) from carrot was immobilized by covalent bonding to a polyacrylamide type support (with free carboxyl groups) activated by water-soluble carbodiimides. The activity of the immobilized enzyme (under optimal reaction conditions of the immobilization) was around 43% of the activity of the free enzyme. The pH-optimum of activity was shifted from 5.1 to 5.3. The immobilization of the enzyme did not change its temperature optimum and the thermal stability of the enzyme was slightly increased after its immobilization. No change in the mode of action of the immobilized enzyme on a polymeric substrate or digalacturonic acid was observed. When sodium pectate was digested with the immobilized enzyme the value of Kmapp was substantially increased and the Vapp-value dropped to 40% of that observed with the free enzyme.

Poly(ethylene terephthalate) immobilized exo-D-galacturonanase

1986 ◽  
Vol 51 (3) ◽  
pp. 723-730 ◽  
Author(s):  
Kveta Heinrichová ◽  
Dagmar Zliechovcová
Keyword(s):  
Ethylene Terephthalate ◽  
Immobilized Enzyme ◽  
Reaction Medium ◽  
Relative Activity ◽  
Acetate Buffer Solution ◽  
Polymeric Substrate ◽  
Buffer Solution ◽  
Ph Optimum ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

Exo-D-galacturonanase (E.C. 3.2.1.67) isolated from carrot was irreversibly adsorbed on poly(ethylene terephthalate) in a 0.1 mol l-1 acetate buffer solution of pH 5.1. Activity of the immobilized enzyme depended on the amount of the enzyme bound to the support, on the ionic strength, and, to a very little extent, also on the pH of the reaction medium during immobilization. Activity of the immobilized enzyme dropped; the greatest relative activity (51.8%) had the preparation composed of 9.12 mg of the enzyme per 1g of the support. The pH optimum for catalytical activity of the immobilized enzyme was identical with that of the dissolved enzyme (5.1). Immobilization of the enzyme did not change its thermal optimum, and its thermal stability did not improve, either. The substrate specificity did not alter by immobilization, no differences were found in the mode of action on the polymeric substrate; digalacturonic acid was degraded by the immobilized enzyme like by the dissolved one. Differences in the kinetics of polymeric substrate degradation by the bonded exo-D-galacturonanase were manifested by a lower V' app value and by an increased K'm value. Exo-D-galacturonanase preparation obtained by adsorption on poly(ethylene terephthalate) was extraordinarily stable during storage at 4 °C, and towards action of salts and pH changes; its operation stability was high.

scholarly journals A New Green Catalyst for Synthesis of bis-Macromonomers of Polyethylene Glycol (PEG)

2020 ◽  
Vol 14 (4) ◽  
pp. 468-473
Author(s):  
Sara Haoue ◽  
◽  
Hodhaifa Derdar ◽  
Mohammed Belbachir ◽  
Amine Harrane ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Reaction Time ◽  
Exchange Process ◽  
Reaction Conditions ◽  
Green Catalyst ◽  
Molecular Weights ◽  
Uv Visible ◽  
Optimal Reaction ◽  
Thermal Stability Of ◽  
End Group

A new method to synthesise polyethylene glycol dimethacrylate (PEGDM) with various molecular weights (1000, 3000, 6000 and 8000 g/mol) of polyethylene glycol (PEG) has been developed. This technique consists in using Maghnite-H+ as eco-catalyst to replace еriethylamine, which is toxic. Maghnite-H+ is a proton exchanged montmorillonite clay which is prepared through a simple exchange process. Synthesis experiments are performed in solution using dichloromethane as solvent in the presence of methacrylic anhydride. The effect of reaction time, temperature, amount of catalyst and amount of methacrylic anhydride is studied in order to find the optimal reaction conditions. The synthesis in solution leads to the best yield (98 %) at room temperature for the reaction time of 5 h. The structure of the obtained macromonomers (PEGDM) is confirmed by FTIR, 1H NMR and 13C NMR, where the methacrylate end groups are clearly visible. Thermogravimetric analysis (TGA) is used to study the thermal stability of these obtained macromonomers. The presence of unsaturated end group was confirmed by UV-Visible analysis.

The Properties and Hydrolysis of Polysiloxanes with Cyanoethyl Groups

2011 ◽  
Vol 306-307 ◽  
pp. 1663-1666
Author(s):  
Rui Fang Guan ◽  
Yu Rong Dong
Keyword(s):  
Mechanical Properties ◽  
Average Molecular Weight ◽  
Dynamic Mechanical Properties ◽  
Carboxyl Groups ◽  
Number Average Molecular Weight ◽  
Reaction Conditions ◽  
Factors Influencing ◽  
Hydrolysis Of ◽  
Optimal Reaction ◽  
Thermal Stability Of

Polysiloxanes with cyanoethyl groups (PDMS-CN) is a useful functional polysiloxanes. In this paper, the polysiloxane with various number average molecular weight (Mn) and cyanoethyl groups were prepared. Mns of PDMS-CN were determined by GPC. The contents of cyanoethyl groups were determined by 1H NMR. The dynamic mechanical properties and thermal stability of PDMS-CN were investigated by DSC and TGA respectively. The hydrolysis of PDMS-CNs give the polysiloxanes with carboxyl groups. The factors influencing the hydrolysis of cyanoethyl groups were discussed by orthogonal array and the optimal reaction conditions were confirmed. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text

scholarly journals LIPASE IMMOBILIZATION ON FIBERS GRAFTED WITH POLYGLYCIDYL METHACHRYLATE

2019 ◽  
Vol 20 (1) ◽  
pp. 12-23
Author(s):  
Maan Alkhatib ◽  
Nik Adlin Bahrudin ◽  
HAMZAH M. SALLEH ◽  
Mohamed M. E. Nasef ◽  
Teo M. Ting
Keyword(s):  
Enzyme Activity ◽  
Storage Stability ◽  
Immobilized Enzyme ◽  
Immobilized Lipase ◽  
Enzyme Concentration ◽  
Free Enzyme ◽  
Effect Of Temperature ◽  
Ph Optimum ◽  
Lipase Enzyme ◽  
Central Composite

ABSTRACT: Lipase enzyme originated from wheat germ was immobilized on nylon -6- grafted with polyglycidyl methachrylate (PGMA). The immobilization of enzyme experiments were designed and studied using face centred central composite design (FCCCD) under response surface methodology (RSM). Prior to immobilization, the polymer was activated with diethyl amine/ethanol to introduce an amine functional group to facilitate covalent bonding with the enzyme. The immobilized and free enzymes were characterized for effect of temperature and pH on enzyme activity, stability, storage and reusability as well as kinetics studies. ANOVA revealed that optimum lipase activity of 0.287 U/ml was achieved at immobilization time of 5 h, pH of 6 and 1.0 mg/ml for enzyme concentration. The optimum temperatures and pH for immobilized and free enzymes were 45 °C and 35 °C, and 8 and 7, respectively. The immobilized enzyme showed higher stability compared to free enzyme. The immobilized enzyme retained 18% of its activity after being recycled 8 times. In a storage stability test, immobilized lipase was able to retain 70% of its activity after being stored for 30 days, while free enzyme activity dropped to 15 % after 20 days of storage. ABSTRAK:Enzim Lipase telah dihasilkan daripada mikroorganisma pegun gandum di atas nilon -6- dan digraf bersama poliglisidel methakrilet (PGMA). Enzim pegun ini direka dan dikaji secara eksperimen menggunakan reka bentuk campuran pusat pada permukaan (FCCCD) di bawah kaedah tindak balas permukaan (RSM). Sebelum menjadi pegun, polimer ini telah diaktifkan dengan dietil amine/ethanol bagi menghasilkan kumpulan fungsi amine bagi membantu ikatan kovalen atom pada enzim. Enzim pegun dan bebas ini telah dikategorikan mengikut kesan enzim ke atas suhu, aktiviti enzim ke atas kesan pH, kestabilan, keboleh-simpanan dan keboleh-gunaan balik, serta ujian tindak balas kinetik. ANOVA membuktikan bahawa aktiviti optimum enzim lipase ini adalah sebanyak 0.287 U/ml telah terhasil selama 5 jam pegun, pada pH 6 dan kepekatan enzim sebanyak 1.0 mg/ml. Suhu dan pH optimum, pada enzim pegun dan enzim bebas ini adalah pada 45 °C dan 35 °C, dan pH 8 dan 7, masing-masing. Enzim pegun ini menunjukkan lebih stabil daripada enzim bebas. Enzim pegun dilihat kekal 18% daripada aktivitinya selepas 8 kali ulangan. Melalui ujian kestabilan simpanan, enzim lipase pegun dapat mengekalkan 70% daripada aktivinya selepas disimpan selama 30 hari, manakala aktiviti enzim bebas telah menurun kepada 15% selepas 20 hari dalam simpanan.

Synthesis of Phosphonates via Michaelis-Arbuzov Reaction

2017 ◽  
Vol 14 (6) ◽  
pp. 883-903 ◽  
Author(s):  
Boppudi Hari Babu ◽  
Gandavaram Syam Prasad ◽  
Chamarthi Naga Raju ◽  
Mandava Venkata Basaveswara Rao
Keyword(s):  
Reaction Times ◽  
Biologically Active ◽  
Fine Tuning ◽  
Arbuzov Reaction ◽  
Reaction Conditions ◽  
Solvent Type ◽  
Potential Applications ◽  
Synthetic Methodologies ◽  
Optimal Reaction ◽  
The Arbuzov Reaction

Background: Michaelis–Arbuzov reaction has played a key role for the synthesis of dialkyl or diaryl phosphonates by reacting various alkyl or aryl halides with trialkyl or triaryl phosphite. This reaction is very versatile in the formation of P-C bond from the reaction of aliphatic halides with phosphinites or phosphites to yield phosphonates, phosphinates, phosphine oxides. The Arbuzov reaction developed some methodologies, possible mechanistic pathways, selectivity, potential applications and biologically active various phosphonates. Objective: The synthesis of phosphonates via Michaelis–Arbuzov reaction with many new and fascinating methodologies were developed and disclosed in the literature, and these are explored in this review. Conclusion: This review has discussed past developments and vast potential applications of Arbuzov reaction in the synthesis of organophosphonates. As presented in this review, various synthetic methodologies were developed to prepare a large variety of phosphonates. Improvements in the reaction conditions of Lewis-acid mediated Arbuzov rearrangement as well as the development of MW-assisted Arbuzov rearrangement were discussed. Finally, to achieve high selectivities and yields, fine-tuning of reaction conditions including solvent type, temperature, and optimal reaction times to be considered.

Immobilized Nanoparticles-Mediated Enzymatic Hydrolysis of Cellulose for Clean Sugar Production: A Novel Approach

2019 ◽  
Vol 15 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Swapnil Gaikwad ◽  
Avinash P. Ingle ◽  
Silvio Silverio da Silva ◽  
Mahendra Rai
Keyword(s):  
Catalytic Activity ◽  
Enzymatic Hydrolysis ◽  
Immobilized Enzyme ◽  
Free Enzyme ◽  
Magnetic Nanomaterials ◽  
Sugar Production ◽  
Cellulase Enzyme ◽  
Enzymatic Hydrolysis Of Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Background: Enzymatic hydrolysis of cellulose is an expensive approach due to the high cost of an enzyme involved in the process. The goal of the current study was to apply magnetic nanomaterials as a support for immobilization of enzyme, which helps in the repeated use of immobilized enzyme for hydrolysis to make the process cost-effective. In addition, it will also provide stability to enzyme and increase its catalytic activity. Objective: The main aim of the present study is to immobilize cellulase enzyme on Magnetic Nanoparticles (MNPs) in order to enable the enzyme to be re-used for clean sugar production from cellulose. Methods: MNPs were synthesized using chemical precipitation methods and characterized by different techniques. Further, cellulase enzyme was immobilized on MNPs and efficacy of free and immobilized cellulase for hydrolysis of cellulose was evaluated. Results: Enzymatic hydrolysis of cellulose by immobilized enzyme showed enhanced catalytic activity after 48 hours compared to free enzyme. In first cycle of hydrolysis, immobilized enzyme hydrolyzed the cellulose and produced 19.5 ± 0.15 gm/L of glucose after 48 hours. On the contrary, free enzyme produced only 13.7 ± 0.25 gm/L of glucose in 48 hours. Immobilized enzyme maintained its stability and produced 6.15 ± 0.15 and 3.03 ± 0.25 gm/L of glucose in second and third cycle, respectively after 48 hours. Conclusion: This study will be very useful for sugar production because of enzyme binding efficiency and admirable reusability of immobilized enzyme, which leads to the significant increase in production of sugar from cellulosic materials.

Amperometric assay of vitamin C using an ascorbate oxidase enzyme electrode

1979 ◽  
Vol 44 (11) ◽  
pp. 3395-3404 ◽  
Author(s):  
Pavel Posádka ◽  
Lumír Macholán
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Oxygen Electrode ◽  
Ascorbate Oxidase ◽  
Current Response ◽  
Reaction Conditions ◽  
Long Term Storage ◽  
Oxidase Enzyme ◽  
Optimal Reaction

An oxygen electrode of the Clark type, coated by a thin, active layer of chemically insolubilized ascorbate oxidase from squash peelings specifically detects by measuring oxygen uptake 10 to 400 μg of ascorbic acid in 3 ml of phosphate buffer. The record of current response to substrate addition lasts 1-2 min. The ascorbic acid values determined in various samples of fruit juices are in good agreement with the data obtained by titration and polarography. The suitable composition of the membrane and its lifetime and stability during long-term storage are described; optimal reaction conditions of vitamin C determination and the possibilities of interference of other compounds are also examined. Of the 35 phenols, aromatic amines and acids tested chlorogenic acid only can cause a positive error provided that the enzyme membrane has been prepared from ascorbate oxidase of high purity.

scholarly journals A Novel Pseudomonas geniculata AGE Family Epimerase/Isomerase and Its Application in d-Mannose Synthesis

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1809
Author(s):  
Zhanzhi Liu ◽  
Ying Li ◽  
Jing Wu ◽  
Sheng Chen
Keyword(s):  
3D Structure ◽  
Three Dimensional ◽  
Optimal Temperature ◽  
Reaction Conditions ◽  
Enzymatic Production ◽  
Physiological Properties ◽  
Potential Applications ◽  
Kinetics Of ◽  
Optimal Reaction ◽  
Gene Age

d-mannose has exhibited excellent physiological properties in the food, pharmaceutical, and feed industries. Therefore, emerging attention has been applied to enzymatic production of d-mannose due to its advantage over chemical synthesis. The gene age of N-acetyl-d-glucosamine 2-epimerase family epimerase/isomerase (AGEase) derived from Pseudomonas geniculata was amplified, and the recombinant P. geniculata AGEase was characterized. The optimal temperature and pH of P. geniculata AGEase were 60 °C and 7.5, respectively. The Km, kcat, and kcat/Km of P. geniculata AGEase for d-mannose were 49.2 ± 8.5 mM, 476.3 ± 4.0 s−1, and 9.7 ± 0.5 s−1·mM−1, respectively. The recombinant P. geniculata AGEase was classified into the YihS enzyme subfamily in the AGE enzyme family by analyzing its substrate specificity and active center of the three-dimensional (3D) structure. Further studies on the kinetics of different substrates showed that the P. geniculata AGEase belongs to the d-mannose isomerase of the YihS enzyme. The P. geniculata AGEase catalyzed the synthesis of d-mannose with d-fructose as a substrate, and the conversion rate was as high as 39.3% with the d-mannose yield of 78.6 g·L−1 under optimal reaction conditions of 200 g·L−1d-fructose and 2.5 U·mL−1P. geniculata AGEase. This novel P. geniculata AGEase has potential applications in the industrial production of d-mannose.

scholarly journals Efficient Degradation of Mordant Blue 9 Using the Fenton-Activated Persulfate System

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2532 ◽  
Author(s):  
Md. Nahid Pervez ◽  
Felix Y. Telegin ◽  
Yingjie Cai ◽  
Dongsheng Xia ◽  
Tiziano Zarra ◽  
...  
Keyword(s):  
Butyl Alcohol ◽  
Textile Dye ◽  
Oh Radicals ◽  
Operational Parameters ◽  
Reaction Conditions ◽  
Tert Butyl Alcohol ◽  
Initial Ph ◽  
Fe Complex ◽  
Optimal Reaction ◽  
Activated Persulfate

In this study, a Fenton-activated persulfate (Fe2+/PS) system was introduced for the efficient degradation of Mordant Blue 9 (MB 9) as a textile dye in an aqueous solution. Results showed that the degradation of MB 9 was markedly influenced by operational parameters, such as initial pH, PS concentration, Fe2+ concentration, and initial dye concentration. Optimal reaction conditions were then determined. Inorganic anions, such as Cl− and HCO3−, enhanced the degradation efficiency of MB 9 under optimal conditions. Addition of HCO3− reduced the degradation performance of MB 9, whereas the addition of Cl− increased the degradation percentage of MB 9. In addition, quenching experiments were conducted using methanol and tert-butyl alcohol as scavengers, and methanol was identified as an effective scavenger. Thus, the degradation of MB 9 was attributed to S O 4 • − and •OH radicals. The degradation and mineralization efficiency of MB 9 was significantly reduced using the conventional Fenton process i.e., Fe2+/ hydrogen peroxide (HP) because of the formation of a Fe complex during degradation. Meanwhile, the Fe2+/persulfate (PS) system improved the degradation and mineralization performance.

Biochemical studies on the production of neuraminidase by environmental isolates of Vibrio cholerae non-O1 from Bulgaria

2011 ◽  
Vol 57 (7) ◽  
pp. 606-610 ◽  
Author(s):  
Rumyana Eneva ◽  
Stephan Engibarov ◽  
Tanya Strateva ◽  
Radoslav Abrashev ◽  
Ignat Abrashev
Keyword(s):  
Vibrio Cholerae ◽  
Pathogenic Bacteria ◽  
Environmental Isolates ◽  
Anaerobic Conditions ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Cholera Vibrio ◽  
Key Factor ◽  
Aeration Conditions ◽  
The One

Neuraminidase is a key factor in the infectious process of many viruses and pathogenic bacteria. The neuraminidase enzyme secreted by the etiological agent of cholera — Vibrio cholerae О1 — is well studied in contrast with the one produced by non-O1/non-O139 V. cholerae. Environmental non-O1/non-O139 V. cholerae isolates from Bulgaria were screened for production of neuraminidase. The presence of the neuraminidase gene nanH was detected in 18.5% of the strains. Тhe strain showing highest activity (30 U/mL), V. cholerae non-O1/13, was used to investigate the enzyme production in several media and at different aeration conditions. The highest production of extracellular neuraminidase was observed under microaerophilic conditions, which is possibly related to its role in the infection of intestine epithelium, where the oxygen content is low. On the other hand, this is another advantage of the microbe in such microaerophilic environments as sediments and lake mud. The highest production of intracellular neuraminidase was observed at anaerobic conditions. The ratio of extracellular to intracellular neuraminidase production in V. cholerae was investigated. The temperature optimum of the enzyme was determined to be 50 °C and the pH optimum to be 5.6–5.8.

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